Genetics

While most cases of breast cancer are sporadic (ie, not inherited), up to 10% are attributable to single-gene hereditary cancer syndromes.^1–4 People with these syndromes have a lifetime risk of breast cancer much higher than in the general population, and the cancers often occur at a much earlier age.

With genetic testing becoming more common, primary care physicians need to be familiar with the known syndromes, associated risks, and evidence-based recommendations for management. Here, we review the management of cancer risk in the most common hereditary breast cancer syndromes, ie:

• Hereditary breast and ovarian cancer syndrome⁵
• Hereditary diffuse gastric cancer
• Cowden syndrome (PTEN hamartoma tumor syndrome)
• Peutz-Jeghers syndrome
• Li-Fraumeni syndrome.

IT TAKES A TEAM, BUT PRIMARY CARE PHYSICIANS ARE CENTRAL

Women who have a hereditary predisposition to breast cancer face complex and emotional decisions about the best ways to manage and reduce their risks. Their management includes close clinical surveillance, chemoprevention, and surgical risk reduction.^1,4

Referral to multiple subspecialists is an important component of these patients’ preventive care. They may need referrals to a cancer genetic counselor, a high-risk breast clinic, a gynecologic oncologist, and counseling services. They may also require referrals to gastroenterologists, colorectal surgeons, endocrinologists, and endocrine surgeons, depending on the syndrome identified.

Find a genetic counselor at www.nsgc.orgConsultation with a certified genetic counselor is critical for patients harboring mutations associated with cancer risk. The National Society of Genetic Counselors maintains a directory of genetic counselors by location and practice specialty at www.nsgc.org. The counselor’s evaluation will provide patients with a detailed explanation of the cancer risks and management guidelines for their particular condition, along with offering diagnostic genetic testing if appropriate. Women with germline mutations who plan to have children should be informed about preimplantation genetic diagnosis and about fertility specialists who can perform this service if they are interested in pursuing it.⁶

Screening and management guidelines for hereditary breast cancer syndromes are evolving. While subspecialists may be involved in enhanced surveillance and preventive care, the primary care physician is the central player, with both a broader perspective and knowledge of the patient’s competing medical issues, risks, and preferences.

In addition to breast cancer, the risk of other malignancies is also higher, with the pattern varying by syndrome (Table 1).^7–20 The management of these additional risks is beyond the scope of this review; however, primary care physicians need to be familiar with these risks to provide adequate referrals.

WHO IS AT INCREASED RISK OF BREAST CANCER?

In considering recommendations to reduce the risk of breast cancer, it is useful to think of a patient as being at either high risk or average risk.

The risk of breast cancer in women in the general population is about 12%, and most cases of breast cancer occur in patients who have no known risk factors for it. “High risk” of breast cancer generally means having more than a 20% lifetime risk (ie, before age 70) of developing the condition.

Even without a hereditary cancer syndrome, a combination of reproductive, environmental, personal, and family history factors can confer a 20% lifetime risk. But for women with hereditary syndromes, the risk far exceeds 20% regardless of such risk factors. It is likely that interactions with reproductive, environmental, and personal risk factors likely affect the individual risk of a woman with a known genetic mutation, and evidence is emerging with regard to further risk stratification.

In an earlier article in this journal, Smith and colleagues²¹ reviewed how to recognize heritable breast cancer syndromes. In general, referral for genetic counseling should be considered for patients and their families who have:

• Early-onset breast cancers (before age 50)
• Bilateral breast cancers at any age
• Ovarian cancers at any age
• “Triple-negative” breast cancers (ie, estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-nonamplified (HER2-negative)
• Male breast cancer at any age
• Cancers affecting multiple individuals and in multiple generations.
• Breast, ovarian, pancreatic or prostate cancer in families with Ashkenazi Jewish ancestry

HEREDITARY BREAST CANCER SYNDROMES

Hereditary breast and ovarian cancer syndrome

The most common of these syndromes is hereditary breast and ovarian cancer syndrome, caused by germline mutations in the tumor-suppressor genes BRCA1 or BRCA2.⁷ The estimated prevalence of BRCA1 mutations is 1 in 250 to 300, and the prevalence of BRCA2 mutations is 1 in 800.^1,4 However, in families of Ashkenazi Jewish ancestry, the population frequency of either a BRCA1 or BRCA2 mutation is approximately 1 in 40.^1,4,6

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%, or 5 to 7 times higher than in the general population, with the risk rising steeply beginning at age 30.^1,5,8 In addition, the lifetime risk of ovarian cancer is nearly 59% in BRCA1 mutation carriers and 17% in BRCA2 mutation carriers.²²

A meta-analysis found that BRCA1 mutation carriers diagnosed with cancer in one breast have a 5-year risk of developing cancer in the other breast of 15%, and BRCA2 mutation carriers have a risk of 9%.²³ Overall, the risk of contralateral breast cancer is about 3% per year.^3,4,24

BRCA1 mutations are strongly associated with triple-negative breast cancers.^1,3,4

Hereditary diffuse gastric cancer

Hereditary diffuse gastric cancer is an autosomal-dominant syndrome associated with mutations in the CDH1 gene, although up to 75% of patients with this syndrome do not have an identifiable CDH1 mutation.^9,25,26 In cases in which there is no identifiable CDH1 mutation, the diagnosis is made on the basis of the patient’s medical and family history.

Hereditary diffuse gastric cancer is associated with an increased risk of the lobular subtype of breast cancer as well as diffuse gastric cancer. The cumulative lifetime risk of breast cancer in women with CDH1 mutations is 39% to 52%,^6,9–11,25 and their lifetime risk of diffuse gastric cancer is 83%.⁹ The combined risk of breast cancer and gastric cancer in women with this syndrome is 90% by age 80.⁹

Cowden syndrome (PTEN hamartoma tumor syndrome)

Cowden syndrome (PTEN hamartoma tumor syndrome) is caused by mutations in PTEN, another tumor-suppressor gene.¹¹ The primary clinical concerns are melanoma and breast, endometrial, thyroid (follicular or papillary), colon, and renal cell cancers. Women with a PTEN mutation have a twofold greater risk of developing any type of cancer than men with a PTEN mutation.¹² The cumulative lifetime risk of invasive breast cancer in women with this syndrome is 70% to 85%.^11–13

Peutz-Jeghers syndrome

Peutz-Jeghers syndrome is an autosomal dominant polyposis disorder caused, in most patients, by a mutation in the serine/threonine kinase tumor-suppressor gene STK11.¹⁴

Patients with Peutz-Jeghers syndrome have higher risks of gastrointestinal, breast, gynecologic (uterine, ovarian, and cervical), pancreatic, and lung cancers. In women, the lifetime risk of breast cancer is 44% to 50% by age 70, regardless of the type of mutation.^6,14,15 Breast cancers associated with Peutz-Jeghers syndrome are usually ductal, and the mean age at diagnosis is 37 years.¹⁶

Li-Fraumeni syndrome

Li-Fraumeni syndrome is an autosomal-dominant disorder caused by germline mutations in the TP53 gene, which codes for a transcription factor associated with cell proliferation and apoptosis.²⁷

Think about other highly penetrant genetic mutations in a young breast cancer patient with no mutation in BRCA1 or BRCA2These mutations confer a lifetime cancer risk of 93% in women (mainly breast cancer) and 68% in men.^1,27 Other cancers associated with TP53 mutations include sarcomas, brain cancer, leukemia, and adrenocortical tumors. Germline TP53 mutations are responsible for approximately 1% of all breast cancers.^1,4

Breast cancers can occur at a young age in patients with a TP53 mutation. Women with TP53 mutations are 18 times more likely to develop breast cancer before age 45 compared with the general population.⁴

It is important to consider a TP53 mutation in premenopausal women or women less than 30 years of age with breast cancer who have no mutations in BRCA1 and BRCA2.¹

MANAGING PATIENTS WITH GENETIC PREDISPOSITION TO BREAST CANCER

Management for patients at high risk fall into three broad categories: clinical surveillance, chemoprevention, and surgical risk reduction. The utility and benefit of each depend to a large degree on the patient’s specific mutation, family history, and comorbidities. Decisions must be shared with the patient.

CLOSE CLINICAL SURVEILLANCE

Consensus guidelines for cancer screening in the syndromes described here are available from the National Comprehensive Cancer Network at www.nccn.org and are summarized in Table 2.^26,28 While the guidelines are broadly applicable to all women with these conditions, some individualization is required based on personal and family medical history.

In general, screening begins at the ages listed in Table 2 or 10 years earlier than the age at which cancer developed in the first affected relative, whichever is earlier. However, screening decisions are shared with the patient and are sometimes affected by significant out-of-pocket costs for the patient and anxiety resulting from the test or subsequent test findings, which must all be considered.

Breast self-awareness and clinical breast examination

Although controversial in the general population, breast self-examination is recommended for patients carrying mutations that increase risk.⁶

Discuss breast self-awareness with all women patients at age 18

A discussion about breast self-awareness is recommended for all women at the age of 18. It should include the signs and symptoms of breast cancer, what feels “normal” to the patient, and what is known about modifiable risk factors for breast cancer. The patient should also be told to report any changes in her personal or family history.

Clinical breast examinations should be done every 6 months, as some cancers are found clinically, particularly in young women with dense tissue, and confirmed by diagnostic imaging and targeted ultrasonography.

Radiographic surveillance

Mammography and magnetic resonance imaging (MRI) are also important components of a breast cancer surveillance regimen in women at high risk. Adherence to a well-formulated plan of clinical and radiographic examinations increases early detection in patients who have a hereditary predisposition to breast cancer.

MRI is more sensitive than mammography and reduces the likelihood of finding advanced cancers by up to 70% compared with mammography in women at high risk of breast cancer.^29–31 The sensitivity of breast MRI alone ranges from 71% to 100%, and the sensitivity increases to 89% to 100% when combined with mammography. In contrast, the sensitivity of mammography alone is 25% to 59%.²⁹ MRI has also been shown to be cost-effective when added to mammography and physical examination in women at high risk.^5,32

Adding MRI to the breast cancer screening regimen has been under discussion and has been endorsed by the American Cancer Society in formal recommendations set forth in 2007 for patients with known hereditary cancer syndromes, in untested first-degree relatives of identified genetic mutation carriers, or in women who have an estimated lifetime risk of breast cancer of 20% or more, as determined by models largely dependent on family history.³³

But MRI has a downside—it is less specific than mammography.^29,33 Its lower specificity (77% to 90% vs 95% with mammography alone) leads to additional radiographic studies and tissue samplings for the “suspicious” lesions discovered. From 3% to 15% of screening breast MRIs result in a biopsy, and the proportion of biopsies that reveal cancer is 13% to 40%.³³ Furthermore, by itself, MRI has not been shown to reduce mortality in any high-risk group.

Mammography remains useful in conjunction with MRI due to its ability to detect breast calcifications, which may be the earliest sign of breast cancer, and ability to detect changes in breast architecture. A typical screening program (Table 2) should incorporate both modalities, commonly offset by 6 months (eg, mammography at baseline, then MRI 6 months later, then mammography again 6 months after that, and so on) to increase the detection of interval cancer development.

Chemoprevention

Chemoprevention means taking medications to reduce the risk. Certain selective estrogen receptor modulators and aromatase inhibitors decrease the risk of invasive breast cancer in healthy women at high risk. These drugs include tamoxifen, which can be used before menopause, and raloxifene, anastrozole, and exemestane, which must be used only after menopause.

Because data are limited, we cannot make any generalized recommendations about chemoprevention in patients with hereditary breast cancer syndromes. Decisions about chemoprevention should take into account the patient’s personal and family histories. Often, a medical oncologist or medical breast specialist can help by discussing the risks and benefits for the individual patient.

Tamoxifen has been the most studied, mainly in BRCA mutation carriers.^6,34–37 As in the general population, tamoxifen reduces the incidence of estrogen receptor-positive breast cancers by 50%.^36–38 It has not been shown to significantly reduce breast cancer risk in premenopausal women with BRCA1 mutations,³⁷ most likely because most cancers that occur in this group are estrogen receptor-negative. In patients with a history of breast cancer, however, tamoxifen has been shown to reduce the risk of developing contralateral breast cancer by 45% to 60% in both BRCA1 and BRCA2 mutation carriers.^6,35

There is also little evidence that giving a chemopreventive agent after bilateral salpingo-oophorectomy reduces the risk further in premenopausal BRCA mutation carriers.³⁵ These patients often receive hormonal therapy with estrogen, which currently would preclude the use of tamoxifen. Tamoxifen in postmenopausal women is associated with a small increased risk of venous thromboembolic disease and endometrial cancer.³⁸

Oral contraceptives reduce the risk of ovarian cancer by up to 50% in BRCA1 mutation carriers and up to 60% in BRCA2 mutation carriers.⁶ However, data conflict on their effect on the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.³⁹

Decisions about chemoprevention with agents other than tamoxifen and in syndromes other than hereditary breast and ovarian cancer syndrome must take into consideration the existing lack of data in this area.

SURGICAL PROPHYLAXIS

Surgical prophylactic options for patients at genetic risk of breast cancer are bilateral mastectomy and bilateral salpingo-oophorectomy.

Prophylactic mastectomy

Bilateral risk-reducing mastectomy reduces the risk of breast cancer by at least 90%^24,39,40 and greatly reduces the need for complex surveillance. Patients are often followed annually clinically, with single-view mammography if they have tissue flap reconstruction.

Nipple-sparing and skin-sparing mastectomies, which facilitate reconstruction and cosmetic outcomes, are an option in the risk-reduction setting and have been shown thus far to be safe.^41–43 In patients with breast cancer, the overall breast cancer recurrence rates with nipple-sparing mastectomy are similar to those of traditional mastectomy and breast conservation treatment.⁴¹

In patients at very high risk of breast cancer, risk-reducing operations also reduce the risk of ultimately needing chemotherapy and radiation to treat breast cancer, as the risk of developing breast cancer is significantly lowered.

The timing of risk-reducing mastectomy depends largely on personal and family medical history and personal choice. Bilateral mastectomy at age 25 results in the greatest survival gain for patients with hereditary breast and ovarian cancer syndrome.⁵ Such precise data are not available for other hereditary cancer syndromes, but it is reasonable to consider bilateral mastectomy as an option for any woman with a highly penetrant genetic mutation that predisposes her to breast cancer. Special consideration in the timing of risk-reducing mastectomy must be given to women with Li-Fraumeni syndrome, as this condition is often associated with an earlier age at breast cancer diagnosis (before age 30).¹

Family planning, sexuality, self-image, and the anxiety associated with both cancer risk and surveillance are all factors women consider when deciding whether and when to undergo mastectomy. A survey of 12 high-risk women who elected prophylactic mastectomy elicited feelings of some regret in 3 of them, while all expressed a sense of relief and reduced anxiety related to both cancer risk and screenings.²⁴ Another group of 14 women surveyed after the surgery reported initial distress related to physical appearance, self-image, and intimacy but also reported a significant decrease in anxiety related to breast cancer risk and were largely satisfied with their decision.⁴⁴

Prophylactic salpingo-oophorectomy

In patients who have pathogenic mutations in BRCA1 or 2, prophylactic salpingo-oophorectomy before age 40 decreases the risk of ovarian cancer by up to 96% and breast cancer by 50%.^1,37,45 This operation, in fact, is the only intervention that has been shown to reduce the mortality rate in patients with a hereditary predisposition to cancer.⁴⁶

We recommend that women with hereditary breast and ovarian cancer syndrome strongly consider prophylactic salpingo-oophorectomy by age 40 or when childbearing is complete for the greatest reduction in risk.^1,5 In 2006, Domchek et al⁴⁶ reported an overall decrease in the mortality rate in BRCA1/2-positive patients who underwent this surgery, but not in breast cancer-specific or ovarian cancer-specific mortality.

On the other hand, removing the ovaries before menopause places women at risk of serious complications associated with premature loss of gonadal hormones, including cardiovascular disease, decreased bone density, reduced sexual satisfaction, dyspareunia, hot flashes, and night sweats.⁴⁷ Therefore, it is generally reserved for women who are also at risk of ovarian cancer.

Hormonal therapy, ie, estrogen therapy for patients who choose complete hysterectomy, and estrogen-progesterone therapy for patients who choose to keep their uterus, reduces menopausal symptoms and symptoms of sexual dissatisfaction and has not thus far been shown to increase breast cancer risk.^1,34 However, this information is from nonrandomized studies, which are inherently limited.

It is important to address and modify risk factors for heart disease and osteoporosis in women with premature surgical menopause, as they may be particularly vulnerable to these conditions.

HEREDITARY BREAST CANCER IN MEN

Fewer than 1% of cases of breast cancer arise in men, and fewer than 1% of cases of cancer in men are breast cancer.

Male breast cancer is more likely than female breast cancer to be estrogen receptor- and progesterone receptor-positive. In an analysis of the Surveillance, Epidemiology, and End Results registry between 1973 and 2005, triple-negative breast cancer was found in 23% of female patients but only 7.6% of male patients.²

Male breast cancer is most common in families with BRCA2, and to a lesser degree, BRCA1 mutations. Other genetic disorders including Li-Fraumeni syndrome, hereditary nonpolyposis colorectal cancer, and Klinefelter syndrome also increase the risk of male breast cancer. A genetic predisposition for breast cancer is present in approximately 10% of male breast cancer patients.² Any man with breast cancer, therefore, should be referred for genetic counseling.

In men, a BRCA2 mutation confers a lifetime risk of breast cancer of 5% to 10%.² This is similar to the lifetime risk of breast cancer for the average woman but it is still significant, as the lifetime risk of breast cancer for the average man is 0.1%.^1,2

Five-year survival rates in male breast cancer range from only 36% to 66%, most likely because it is usually diagnosed in later stages, as men are not routinely screened for breast cancer. In men with known hereditary susceptibility, National Comprehensive Cancer Network guidelines recommend that they be educated about and begin breast self-examination at the age of 35 and be clinically examined every 12 months starting at age 35.⁴⁸ There are limited data to support breast imaging in men. High-risk surveillance with MRI screening in this group is not recommended. Prostate cancer screening is recommended for men with BRCA2 mutations starting at age 40, and should be considered for men with BRCA1 mutations starting at age 40.

No specific guidelines exist for pancreatic cancer and melanoma, but screening may be individualized based on cancers observed in the family.

While most cases of breast cancer are sporadic (ie, not inherited), up to 10% are attributable to single-gene hereditary cancer syndromes.^1–4 People with these syndromes have a lifetime risk of breast cancer much higher than in the general population, and the cancers often occur at a much earlier age.

With genetic testing becoming more common, primary care physicians need to be familiar with the known syndromes, associated risks, and evidence-based recommendations for management. Here, we review the management of cancer risk in the most common hereditary breast cancer syndromes, ie:

• Hereditary breast and ovarian cancer syndrome⁵
• Hereditary diffuse gastric cancer
• Cowden syndrome (PTEN hamartoma tumor syndrome)
• Peutz-Jeghers syndrome
• Li-Fraumeni syndrome.

IT TAKES A TEAM, BUT PRIMARY CARE PHYSICIANS ARE CENTRAL

Women who have a hereditary predisposition to breast cancer face complex and emotional decisions about the best ways to manage and reduce their risks. Their management includes close clinical surveillance, chemoprevention, and surgical risk reduction.^1,4

Referral to multiple subspecialists is an important component of these patients’ preventive care. They may need referrals to a cancer genetic counselor, a high-risk breast clinic, a gynecologic oncologist, and counseling services. They may also require referrals to gastroenterologists, colorectal surgeons, endocrinologists, and endocrine surgeons, depending on the syndrome identified.

Find a genetic counselor at www.nsgc.orgConsultation with a certified genetic counselor is critical for patients harboring mutations associated with cancer risk. The National Society of Genetic Counselors maintains a directory of genetic counselors by location and practice specialty at www.nsgc.org. The counselor’s evaluation will provide patients with a detailed explanation of the cancer risks and management guidelines for their particular condition, along with offering diagnostic genetic testing if appropriate. Women with germline mutations who plan to have children should be informed about preimplantation genetic diagnosis and about fertility specialists who can perform this service if they are interested in pursuing it.⁶

Screening and management guidelines for hereditary breast cancer syndromes are evolving. While subspecialists may be involved in enhanced surveillance and preventive care, the primary care physician is the central player, with both a broader perspective and knowledge of the patient’s competing medical issues, risks, and preferences.

In addition to breast cancer, the risk of other malignancies is also higher, with the pattern varying by syndrome (Table 1).^7–20 The management of these additional risks is beyond the scope of this review; however, primary care physicians need to be familiar with these risks to provide adequate referrals.

WHO IS AT INCREASED RISK OF BREAST CANCER?

In considering recommendations to reduce the risk of breast cancer, it is useful to think of a patient as being at either high risk or average risk.

The risk of breast cancer in women in the general population is about 12%, and most cases of breast cancer occur in patients who have no known risk factors for it. “High risk” of breast cancer generally means having more than a 20% lifetime risk (ie, before age 70) of developing the condition.

Even without a hereditary cancer syndrome, a combination of reproductive, environmental, personal, and family history factors can confer a 20% lifetime risk. But for women with hereditary syndromes, the risk far exceeds 20% regardless of such risk factors. It is likely that interactions with reproductive, environmental, and personal risk factors likely affect the individual risk of a woman with a known genetic mutation, and evidence is emerging with regard to further risk stratification.

In an earlier article in this journal, Smith and colleagues²¹ reviewed how to recognize heritable breast cancer syndromes. In general, referral for genetic counseling should be considered for patients and their families who have:

• Early-onset breast cancers (before age 50)
• Bilateral breast cancers at any age
• Ovarian cancers at any age
• “Triple-negative” breast cancers (ie, estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-nonamplified (HER2-negative)
• Male breast cancer at any age
• Cancers affecting multiple individuals and in multiple generations.
• Breast, ovarian, pancreatic or prostate cancer in families with Ashkenazi Jewish ancestry

HEREDITARY BREAST CANCER SYNDROMES

Hereditary breast and ovarian cancer syndrome

The most common of these syndromes is hereditary breast and ovarian cancer syndrome, caused by germline mutations in the tumor-suppressor genes BRCA1 or BRCA2.⁷ The estimated prevalence of BRCA1 mutations is 1 in 250 to 300, and the prevalence of BRCA2 mutations is 1 in 800.^1,4 However, in families of Ashkenazi Jewish ancestry, the population frequency of either a BRCA1 or BRCA2 mutation is approximately 1 in 40.^1,4,6

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%, or 5 to 7 times higher than in the general population, with the risk rising steeply beginning at age 30.^1,5,8 In addition, the lifetime risk of ovarian cancer is nearly 59% in BRCA1 mutation carriers and 17% in BRCA2 mutation carriers.²²

A meta-analysis found that BRCA1 mutation carriers diagnosed with cancer in one breast have a 5-year risk of developing cancer in the other breast of 15%, and BRCA2 mutation carriers have a risk of 9%.²³ Overall, the risk of contralateral breast cancer is about 3% per year.^3,4,24

BRCA1 mutations are strongly associated with triple-negative breast cancers.^1,3,4

Hereditary diffuse gastric cancer

Hereditary diffuse gastric cancer is an autosomal-dominant syndrome associated with mutations in the CDH1 gene, although up to 75% of patients with this syndrome do not have an identifiable CDH1 mutation.^9,25,26 In cases in which there is no identifiable CDH1 mutation, the diagnosis is made on the basis of the patient’s medical and family history.

Hereditary diffuse gastric cancer is associated with an increased risk of the lobular subtype of breast cancer as well as diffuse gastric cancer. The cumulative lifetime risk of breast cancer in women with CDH1 mutations is 39% to 52%,^6,9–11,25 and their lifetime risk of diffuse gastric cancer is 83%.⁹ The combined risk of breast cancer and gastric cancer in women with this syndrome is 90% by age 80.⁹

Cowden syndrome (PTEN hamartoma tumor syndrome)

Cowden syndrome (PTEN hamartoma tumor syndrome) is caused by mutations in PTEN, another tumor-suppressor gene.¹¹ The primary clinical concerns are melanoma and breast, endometrial, thyroid (follicular or papillary), colon, and renal cell cancers. Women with a PTEN mutation have a twofold greater risk of developing any type of cancer than men with a PTEN mutation.¹² The cumulative lifetime risk of invasive breast cancer in women with this syndrome is 70% to 85%.^11–13

Peutz-Jeghers syndrome

Peutz-Jeghers syndrome is an autosomal dominant polyposis disorder caused, in most patients, by a mutation in the serine/threonine kinase tumor-suppressor gene STK11.¹⁴

Patients with Peutz-Jeghers syndrome have higher risks of gastrointestinal, breast, gynecologic (uterine, ovarian, and cervical), pancreatic, and lung cancers. In women, the lifetime risk of breast cancer is 44% to 50% by age 70, regardless of the type of mutation.^6,14,15 Breast cancers associated with Peutz-Jeghers syndrome are usually ductal, and the mean age at diagnosis is 37 years.¹⁶

Li-Fraumeni syndrome

Li-Fraumeni syndrome is an autosomal-dominant disorder caused by germline mutations in the TP53 gene, which codes for a transcription factor associated with cell proliferation and apoptosis.²⁷

Think about other highly penetrant genetic mutations in a young breast cancer patient with no mutation in BRCA1 or BRCA2These mutations confer a lifetime cancer risk of 93% in women (mainly breast cancer) and 68% in men.^1,27 Other cancers associated with TP53 mutations include sarcomas, brain cancer, leukemia, and adrenocortical tumors. Germline TP53 mutations are responsible for approximately 1% of all breast cancers.^1,4

Breast cancers can occur at a young age in patients with a TP53 mutation. Women with TP53 mutations are 18 times more likely to develop breast cancer before age 45 compared with the general population.⁴

It is important to consider a TP53 mutation in premenopausal women or women less than 30 years of age with breast cancer who have no mutations in BRCA1 and BRCA2.¹

MANAGING PATIENTS WITH GENETIC PREDISPOSITION TO BREAST CANCER

Management for patients at high risk fall into three broad categories: clinical surveillance, chemoprevention, and surgical risk reduction. The utility and benefit of each depend to a large degree on the patient’s specific mutation, family history, and comorbidities. Decisions must be shared with the patient.

CLOSE CLINICAL SURVEILLANCE

Consensus guidelines for cancer screening in the syndromes described here are available from the National Comprehensive Cancer Network at www.nccn.org and are summarized in Table 2.^26,28 While the guidelines are broadly applicable to all women with these conditions, some individualization is required based on personal and family medical history.

In general, screening begins at the ages listed in Table 2 or 10 years earlier than the age at which cancer developed in the first affected relative, whichever is earlier. However, screening decisions are shared with the patient and are sometimes affected by significant out-of-pocket costs for the patient and anxiety resulting from the test or subsequent test findings, which must all be considered.

Breast self-awareness and clinical breast examination

Although controversial in the general population, breast self-examination is recommended for patients carrying mutations that increase risk.⁶

Discuss breast self-awareness with all women patients at age 18

A discussion about breast self-awareness is recommended for all women at the age of 18. It should include the signs and symptoms of breast cancer, what feels “normal” to the patient, and what is known about modifiable risk factors for breast cancer. The patient should also be told to report any changes in her personal or family history.

Clinical breast examinations should be done every 6 months, as some cancers are found clinically, particularly in young women with dense tissue, and confirmed by diagnostic imaging and targeted ultrasonography.

Radiographic surveillance

Mammography and magnetic resonance imaging (MRI) are also important components of a breast cancer surveillance regimen in women at high risk. Adherence to a well-formulated plan of clinical and radiographic examinations increases early detection in patients who have a hereditary predisposition to breast cancer.

MRI is more sensitive than mammography and reduces the likelihood of finding advanced cancers by up to 70% compared with mammography in women at high risk of breast cancer.^29–31 The sensitivity of breast MRI alone ranges from 71% to 100%, and the sensitivity increases to 89% to 100% when combined with mammography. In contrast, the sensitivity of mammography alone is 25% to 59%.²⁹ MRI has also been shown to be cost-effective when added to mammography and physical examination in women at high risk.^5,32

Adding MRI to the breast cancer screening regimen has been under discussion and has been endorsed by the American Cancer Society in formal recommendations set forth in 2007 for patients with known hereditary cancer syndromes, in untested first-degree relatives of identified genetic mutation carriers, or in women who have an estimated lifetime risk of breast cancer of 20% or more, as determined by models largely dependent on family history.³³

But MRI has a downside—it is less specific than mammography.^29,33 Its lower specificity (77% to 90% vs 95% with mammography alone) leads to additional radiographic studies and tissue samplings for the “suspicious” lesions discovered. From 3% to 15% of screening breast MRIs result in a biopsy, and the proportion of biopsies that reveal cancer is 13% to 40%.³³ Furthermore, by itself, MRI has not been shown to reduce mortality in any high-risk group.

Mammography remains useful in conjunction with MRI due to its ability to detect breast calcifications, which may be the earliest sign of breast cancer, and ability to detect changes in breast architecture. A typical screening program (Table 2) should incorporate both modalities, commonly offset by 6 months (eg, mammography at baseline, then MRI 6 months later, then mammography again 6 months after that, and so on) to increase the detection of interval cancer development.

Chemoprevention

Chemoprevention means taking medications to reduce the risk. Certain selective estrogen receptor modulators and aromatase inhibitors decrease the risk of invasive breast cancer in healthy women at high risk. These drugs include tamoxifen, which can be used before menopause, and raloxifene, anastrozole, and exemestane, which must be used only after menopause.

Because data are limited, we cannot make any generalized recommendations about chemoprevention in patients with hereditary breast cancer syndromes. Decisions about chemoprevention should take into account the patient’s personal and family histories. Often, a medical oncologist or medical breast specialist can help by discussing the risks and benefits for the individual patient.

Tamoxifen has been the most studied, mainly in BRCA mutation carriers.^6,34–37 As in the general population, tamoxifen reduces the incidence of estrogen receptor-positive breast cancers by 50%.^36–38 It has not been shown to significantly reduce breast cancer risk in premenopausal women with BRCA1 mutations,³⁷ most likely because most cancers that occur in this group are estrogen receptor-negative. In patients with a history of breast cancer, however, tamoxifen has been shown to reduce the risk of developing contralateral breast cancer by 45% to 60% in both BRCA1 and BRCA2 mutation carriers.^6,35

There is also little evidence that giving a chemopreventive agent after bilateral salpingo-oophorectomy reduces the risk further in premenopausal BRCA mutation carriers.³⁵ These patients often receive hormonal therapy with estrogen, which currently would preclude the use of tamoxifen. Tamoxifen in postmenopausal women is associated with a small increased risk of venous thromboembolic disease and endometrial cancer.³⁸

Oral contraceptives reduce the risk of ovarian cancer by up to 50% in BRCA1 mutation carriers and up to 60% in BRCA2 mutation carriers.⁶ However, data conflict on their effect on the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.³⁹

Decisions about chemoprevention with agents other than tamoxifen and in syndromes other than hereditary breast and ovarian cancer syndrome must take into consideration the existing lack of data in this area.

SURGICAL PROPHYLAXIS

Surgical prophylactic options for patients at genetic risk of breast cancer are bilateral mastectomy and bilateral salpingo-oophorectomy.

Prophylactic mastectomy

Bilateral risk-reducing mastectomy reduces the risk of breast cancer by at least 90%^24,39,40 and greatly reduces the need for complex surveillance. Patients are often followed annually clinically, with single-view mammography if they have tissue flap reconstruction.

Nipple-sparing and skin-sparing mastectomies, which facilitate reconstruction and cosmetic outcomes, are an option in the risk-reduction setting and have been shown thus far to be safe.^41–43 In patients with breast cancer, the overall breast cancer recurrence rates with nipple-sparing mastectomy are similar to those of traditional mastectomy and breast conservation treatment.⁴¹

In patients at very high risk of breast cancer, risk-reducing operations also reduce the risk of ultimately needing chemotherapy and radiation to treat breast cancer, as the risk of developing breast cancer is significantly lowered.

The timing of risk-reducing mastectomy depends largely on personal and family medical history and personal choice. Bilateral mastectomy at age 25 results in the greatest survival gain for patients with hereditary breast and ovarian cancer syndrome.⁵ Such precise data are not available for other hereditary cancer syndromes, but it is reasonable to consider bilateral mastectomy as an option for any woman with a highly penetrant genetic mutation that predisposes her to breast cancer. Special consideration in the timing of risk-reducing mastectomy must be given to women with Li-Fraumeni syndrome, as this condition is often associated with an earlier age at breast cancer diagnosis (before age 30).¹

Family planning, sexuality, self-image, and the anxiety associated with both cancer risk and surveillance are all factors women consider when deciding whether and when to undergo mastectomy. A survey of 12 high-risk women who elected prophylactic mastectomy elicited feelings of some regret in 3 of them, while all expressed a sense of relief and reduced anxiety related to both cancer risk and screenings.²⁴ Another group of 14 women surveyed after the surgery reported initial distress related to physical appearance, self-image, and intimacy but also reported a significant decrease in anxiety related to breast cancer risk and were largely satisfied with their decision.⁴⁴

Prophylactic salpingo-oophorectomy

In patients who have pathogenic mutations in BRCA1 or 2, prophylactic salpingo-oophorectomy before age 40 decreases the risk of ovarian cancer by up to 96% and breast cancer by 50%.^1,37,45 This operation, in fact, is the only intervention that has been shown to reduce the mortality rate in patients with a hereditary predisposition to cancer.⁴⁶

We recommend that women with hereditary breast and ovarian cancer syndrome strongly consider prophylactic salpingo-oophorectomy by age 40 or when childbearing is complete for the greatest reduction in risk.^1,5 In 2006, Domchek et al⁴⁶ reported an overall decrease in the mortality rate in BRCA1/2-positive patients who underwent this surgery, but not in breast cancer-specific or ovarian cancer-specific mortality.

On the other hand, removing the ovaries before menopause places women at risk of serious complications associated with premature loss of gonadal hormones, including cardiovascular disease, decreased bone density, reduced sexual satisfaction, dyspareunia, hot flashes, and night sweats.⁴⁷ Therefore, it is generally reserved for women who are also at risk of ovarian cancer.

Hormonal therapy, ie, estrogen therapy for patients who choose complete hysterectomy, and estrogen-progesterone therapy for patients who choose to keep their uterus, reduces menopausal symptoms and symptoms of sexual dissatisfaction and has not thus far been shown to increase breast cancer risk.^1,34 However, this information is from nonrandomized studies, which are inherently limited.

It is important to address and modify risk factors for heart disease and osteoporosis in women with premature surgical menopause, as they may be particularly vulnerable to these conditions.

HEREDITARY BREAST CANCER IN MEN

Fewer than 1% of cases of breast cancer arise in men, and fewer than 1% of cases of cancer in men are breast cancer.

Male breast cancer is more likely than female breast cancer to be estrogen receptor- and progesterone receptor-positive. In an analysis of the Surveillance, Epidemiology, and End Results registry between 1973 and 2005, triple-negative breast cancer was found in 23% of female patients but only 7.6% of male patients.²

Male breast cancer is most common in families with BRCA2, and to a lesser degree, BRCA1 mutations. Other genetic disorders including Li-Fraumeni syndrome, hereditary nonpolyposis colorectal cancer, and Klinefelter syndrome also increase the risk of male breast cancer. A genetic predisposition for breast cancer is present in approximately 10% of male breast cancer patients.² Any man with breast cancer, therefore, should be referred for genetic counseling.

In men, a BRCA2 mutation confers a lifetime risk of breast cancer of 5% to 10%.² This is similar to the lifetime risk of breast cancer for the average woman but it is still significant, as the lifetime risk of breast cancer for the average man is 0.1%.^1,2

Five-year survival rates in male breast cancer range from only 36% to 66%, most likely because it is usually diagnosed in later stages, as men are not routinely screened for breast cancer. In men with known hereditary susceptibility, National Comprehensive Cancer Network guidelines recommend that they be educated about and begin breast self-examination at the age of 35 and be clinically examined every 12 months starting at age 35.⁴⁸ There are limited data to support breast imaging in men. High-risk surveillance with MRI screening in this group is not recommended. Prostate cancer screening is recommended for men with BRCA2 mutations starting at age 40, and should be considered for men with BRCA1 mutations starting at age 40.

No specific guidelines exist for pancreatic cancer and melanoma, but screening may be individualized based on cancers observed in the family.

While most cases of breast cancer are sporadic (ie, not inherited), up to 10% are attributable to single-gene hereditary cancer syndromes.^1–4 People with these syndromes have a lifetime risk of breast cancer much higher than in the general population, and the cancers often occur at a much earlier age.

With genetic testing becoming more common, primary care physicians need to be familiar with the known syndromes, associated risks, and evidence-based recommendations for management. Here, we review the management of cancer risk in the most common hereditary breast cancer syndromes, ie:

• Hereditary breast and ovarian cancer syndrome⁵
• Hereditary diffuse gastric cancer
• Cowden syndrome (PTEN hamartoma tumor syndrome)
• Peutz-Jeghers syndrome
• Li-Fraumeni syndrome.

IT TAKES A TEAM, BUT PRIMARY CARE PHYSICIANS ARE CENTRAL

Women who have a hereditary predisposition to breast cancer face complex and emotional decisions about the best ways to manage and reduce their risks. Their management includes close clinical surveillance, chemoprevention, and surgical risk reduction.^1,4

Referral to multiple subspecialists is an important component of these patients’ preventive care. They may need referrals to a cancer genetic counselor, a high-risk breast clinic, a gynecologic oncologist, and counseling services. They may also require referrals to gastroenterologists, colorectal surgeons, endocrinologists, and endocrine surgeons, depending on the syndrome identified.

Find a genetic counselor at www.nsgc.orgConsultation with a certified genetic counselor is critical for patients harboring mutations associated with cancer risk. The National Society of Genetic Counselors maintains a directory of genetic counselors by location and practice specialty at www.nsgc.org. The counselor’s evaluation will provide patients with a detailed explanation of the cancer risks and management guidelines for their particular condition, along with offering diagnostic genetic testing if appropriate. Women with germline mutations who plan to have children should be informed about preimplantation genetic diagnosis and about fertility specialists who can perform this service if they are interested in pursuing it.⁶

Screening and management guidelines for hereditary breast cancer syndromes are evolving. While subspecialists may be involved in enhanced surveillance and preventive care, the primary care physician is the central player, with both a broader perspective and knowledge of the patient’s competing medical issues, risks, and preferences.

In addition to breast cancer, the risk of other malignancies is also higher, with the pattern varying by syndrome (Table 1).^7–20 The management of these additional risks is beyond the scope of this review; however, primary care physicians need to be familiar with these risks to provide adequate referrals.

WHO IS AT INCREASED RISK OF BREAST CANCER?

In considering recommendations to reduce the risk of breast cancer, it is useful to think of a patient as being at either high risk or average risk.

The risk of breast cancer in women in the general population is about 12%, and most cases of breast cancer occur in patients who have no known risk factors for it. “High risk” of breast cancer generally means having more than a 20% lifetime risk (ie, before age 70) of developing the condition.

Even without a hereditary cancer syndrome, a combination of reproductive, environmental, personal, and family history factors can confer a 20% lifetime risk. But for women with hereditary syndromes, the risk far exceeds 20% regardless of such risk factors. It is likely that interactions with reproductive, environmental, and personal risk factors likely affect the individual risk of a woman with a known genetic mutation, and evidence is emerging with regard to further risk stratification.

In an earlier article in this journal, Smith and colleagues²¹ reviewed how to recognize heritable breast cancer syndromes. In general, referral for genetic counseling should be considered for patients and their families who have:

• Early-onset breast cancers (before age 50)
• Bilateral breast cancers at any age
• Ovarian cancers at any age
• “Triple-negative” breast cancers (ie, estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-nonamplified (HER2-negative)
• Male breast cancer at any age
• Cancers affecting multiple individuals and in multiple generations.
• Breast, ovarian, pancreatic or prostate cancer in families with Ashkenazi Jewish ancestry

HEREDITARY BREAST CANCER SYNDROMES

Hereditary breast and ovarian cancer syndrome

The most common of these syndromes is hereditary breast and ovarian cancer syndrome, caused by germline mutations in the tumor-suppressor genes BRCA1 or BRCA2.⁷ The estimated prevalence of BRCA1 mutations is 1 in 250 to 300, and the prevalence of BRCA2 mutations is 1 in 800.^1,4 However, in families of Ashkenazi Jewish ancestry, the population frequency of either a BRCA1 or BRCA2 mutation is approximately 1 in 40.^1,4,6

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%

Women with BRCA1 or BRCA2 mutations have a lifetime risk of breast cancer of up to 87%, or 5 to 7 times higher than in the general population, with the risk rising steeply beginning at age 30.^1,5,8 In addition, the lifetime risk of ovarian cancer is nearly 59% in BRCA1 mutation carriers and 17% in BRCA2 mutation carriers.²²

A meta-analysis found that BRCA1 mutation carriers diagnosed with cancer in one breast have a 5-year risk of developing cancer in the other breast of 15%, and BRCA2 mutation carriers have a risk of 9%.²³ Overall, the risk of contralateral breast cancer is about 3% per year.^3,4,24

BRCA1 mutations are strongly associated with triple-negative breast cancers.^1,3,4

Hereditary diffuse gastric cancer

Hereditary diffuse gastric cancer is an autosomal-dominant syndrome associated with mutations in the CDH1 gene, although up to 75% of patients with this syndrome do not have an identifiable CDH1 mutation.^9,25,26 In cases in which there is no identifiable CDH1 mutation, the diagnosis is made on the basis of the patient’s medical and family history.

Hereditary diffuse gastric cancer is associated with an increased risk of the lobular subtype of breast cancer as well as diffuse gastric cancer. The cumulative lifetime risk of breast cancer in women with CDH1 mutations is 39% to 52%,^6,9–11,25 and their lifetime risk of diffuse gastric cancer is 83%.⁹ The combined risk of breast cancer and gastric cancer in women with this syndrome is 90% by age 80.⁹

Cowden syndrome (PTEN hamartoma tumor syndrome)

Cowden syndrome (PTEN hamartoma tumor syndrome) is caused by mutations in PTEN, another tumor-suppressor gene.¹¹ The primary clinical concerns are melanoma and breast, endometrial, thyroid (follicular or papillary), colon, and renal cell cancers. Women with a PTEN mutation have a twofold greater risk of developing any type of cancer than men with a PTEN mutation.¹² The cumulative lifetime risk of invasive breast cancer in women with this syndrome is 70% to 85%.^11–13

Peutz-Jeghers syndrome

Peutz-Jeghers syndrome is an autosomal dominant polyposis disorder caused, in most patients, by a mutation in the serine/threonine kinase tumor-suppressor gene STK11.¹⁴

Patients with Peutz-Jeghers syndrome have higher risks of gastrointestinal, breast, gynecologic (uterine, ovarian, and cervical), pancreatic, and lung cancers. In women, the lifetime risk of breast cancer is 44% to 50% by age 70, regardless of the type of mutation.^6,14,15 Breast cancers associated with Peutz-Jeghers syndrome are usually ductal, and the mean age at diagnosis is 37 years.¹⁶

Li-Fraumeni syndrome

Li-Fraumeni syndrome is an autosomal-dominant disorder caused by germline mutations in the TP53 gene, which codes for a transcription factor associated with cell proliferation and apoptosis.²⁷

Think about other highly penetrant genetic mutations in a young breast cancer patient with no mutation in BRCA1 or BRCA2These mutations confer a lifetime cancer risk of 93% in women (mainly breast cancer) and 68% in men.^1,27 Other cancers associated with TP53 mutations include sarcomas, brain cancer, leukemia, and adrenocortical tumors. Germline TP53 mutations are responsible for approximately 1% of all breast cancers.^1,4

Breast cancers can occur at a young age in patients with a TP53 mutation. Women with TP53 mutations are 18 times more likely to develop breast cancer before age 45 compared with the general population.⁴

It is important to consider a TP53 mutation in premenopausal women or women less than 30 years of age with breast cancer who have no mutations in BRCA1 and BRCA2.¹

MANAGING PATIENTS WITH GENETIC PREDISPOSITION TO BREAST CANCER

Management for patients at high risk fall into three broad categories: clinical surveillance, chemoprevention, and surgical risk reduction. The utility and benefit of each depend to a large degree on the patient’s specific mutation, family history, and comorbidities. Decisions must be shared with the patient.

CLOSE CLINICAL SURVEILLANCE

Consensus guidelines for cancer screening in the syndromes described here are available from the National Comprehensive Cancer Network at www.nccn.org and are summarized in Table 2.^26,28 While the guidelines are broadly applicable to all women with these conditions, some individualization is required based on personal and family medical history.

In general, screening begins at the ages listed in Table 2 or 10 years earlier than the age at which cancer developed in the first affected relative, whichever is earlier. However, screening decisions are shared with the patient and are sometimes affected by significant out-of-pocket costs for the patient and anxiety resulting from the test or subsequent test findings, which must all be considered.

Breast self-awareness and clinical breast examination

Although controversial in the general population, breast self-examination is recommended for patients carrying mutations that increase risk.⁶

Discuss breast self-awareness with all women patients at age 18

A discussion about breast self-awareness is recommended for all women at the age of 18. It should include the signs and symptoms of breast cancer, what feels “normal” to the patient, and what is known about modifiable risk factors for breast cancer. The patient should also be told to report any changes in her personal or family history.

Clinical breast examinations should be done every 6 months, as some cancers are found clinically, particularly in young women with dense tissue, and confirmed by diagnostic imaging and targeted ultrasonography.

Radiographic surveillance

Mammography and magnetic resonance imaging (MRI) are also important components of a breast cancer surveillance regimen in women at high risk. Adherence to a well-formulated plan of clinical and radiographic examinations increases early detection in patients who have a hereditary predisposition to breast cancer.

MRI is more sensitive than mammography and reduces the likelihood of finding advanced cancers by up to 70% compared with mammography in women at high risk of breast cancer.^29–31 The sensitivity of breast MRI alone ranges from 71% to 100%, and the sensitivity increases to 89% to 100% when combined with mammography. In contrast, the sensitivity of mammography alone is 25% to 59%.²⁹ MRI has also been shown to be cost-effective when added to mammography and physical examination in women at high risk.^5,32

Adding MRI to the breast cancer screening regimen has been under discussion and has been endorsed by the American Cancer Society in formal recommendations set forth in 2007 for patients with known hereditary cancer syndromes, in untested first-degree relatives of identified genetic mutation carriers, or in women who have an estimated lifetime risk of breast cancer of 20% or more, as determined by models largely dependent on family history.³³

But MRI has a downside—it is less specific than mammography.^29,33 Its lower specificity (77% to 90% vs 95% with mammography alone) leads to additional radiographic studies and tissue samplings for the “suspicious” lesions discovered. From 3% to 15% of screening breast MRIs result in a biopsy, and the proportion of biopsies that reveal cancer is 13% to 40%.³³ Furthermore, by itself, MRI has not been shown to reduce mortality in any high-risk group.

Mammography remains useful in conjunction with MRI due to its ability to detect breast calcifications, which may be the earliest sign of breast cancer, and ability to detect changes in breast architecture. A typical screening program (Table 2) should incorporate both modalities, commonly offset by 6 months (eg, mammography at baseline, then MRI 6 months later, then mammography again 6 months after that, and so on) to increase the detection of interval cancer development.

Chemoprevention

Chemoprevention means taking medications to reduce the risk. Certain selective estrogen receptor modulators and aromatase inhibitors decrease the risk of invasive breast cancer in healthy women at high risk. These drugs include tamoxifen, which can be used before menopause, and raloxifene, anastrozole, and exemestane, which must be used only after menopause.

Because data are limited, we cannot make any generalized recommendations about chemoprevention in patients with hereditary breast cancer syndromes. Decisions about chemoprevention should take into account the patient’s personal and family histories. Often, a medical oncologist or medical breast specialist can help by discussing the risks and benefits for the individual patient.

Tamoxifen has been the most studied, mainly in BRCA mutation carriers.^6,34–37 As in the general population, tamoxifen reduces the incidence of estrogen receptor-positive breast cancers by 50%.^36–38 It has not been shown to significantly reduce breast cancer risk in premenopausal women with BRCA1 mutations,³⁷ most likely because most cancers that occur in this group are estrogen receptor-negative. In patients with a history of breast cancer, however, tamoxifen has been shown to reduce the risk of developing contralateral breast cancer by 45% to 60% in both BRCA1 and BRCA2 mutation carriers.^6,35

There is also little evidence that giving a chemopreventive agent after bilateral salpingo-oophorectomy reduces the risk further in premenopausal BRCA mutation carriers.³⁵ These patients often receive hormonal therapy with estrogen, which currently would preclude the use of tamoxifen. Tamoxifen in postmenopausal women is associated with a small increased risk of venous thromboembolic disease and endometrial cancer.³⁸

Oral contraceptives reduce the risk of ovarian cancer by up to 50% in BRCA1 mutation carriers and up to 60% in BRCA2 mutation carriers.⁶ However, data conflict on their effect on the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.³⁹

Decisions about chemoprevention with agents other than tamoxifen and in syndromes other than hereditary breast and ovarian cancer syndrome must take into consideration the existing lack of data in this area.

SURGICAL PROPHYLAXIS

Surgical prophylactic options for patients at genetic risk of breast cancer are bilateral mastectomy and bilateral salpingo-oophorectomy.

Prophylactic mastectomy

Bilateral risk-reducing mastectomy reduces the risk of breast cancer by at least 90%^24,39,40 and greatly reduces the need for complex surveillance. Patients are often followed annually clinically, with single-view mammography if they have tissue flap reconstruction.

Nipple-sparing and skin-sparing mastectomies, which facilitate reconstruction and cosmetic outcomes, are an option in the risk-reduction setting and have been shown thus far to be safe.^41–43 In patients with breast cancer, the overall breast cancer recurrence rates with nipple-sparing mastectomy are similar to those of traditional mastectomy and breast conservation treatment.⁴¹

In patients at very high risk of breast cancer, risk-reducing operations also reduce the risk of ultimately needing chemotherapy and radiation to treat breast cancer, as the risk of developing breast cancer is significantly lowered.

The timing of risk-reducing mastectomy depends largely on personal and family medical history and personal choice. Bilateral mastectomy at age 25 results in the greatest survival gain for patients with hereditary breast and ovarian cancer syndrome.⁵ Such precise data are not available for other hereditary cancer syndromes, but it is reasonable to consider bilateral mastectomy as an option for any woman with a highly penetrant genetic mutation that predisposes her to breast cancer. Special consideration in the timing of risk-reducing mastectomy must be given to women with Li-Fraumeni syndrome, as this condition is often associated with an earlier age at breast cancer diagnosis (before age 30).¹

Family planning, sexuality, self-image, and the anxiety associated with both cancer risk and surveillance are all factors women consider when deciding whether and when to undergo mastectomy. A survey of 12 high-risk women who elected prophylactic mastectomy elicited feelings of some regret in 3 of them, while all expressed a sense of relief and reduced anxiety related to both cancer risk and screenings.²⁴ Another group of 14 women surveyed after the surgery reported initial distress related to physical appearance, self-image, and intimacy but also reported a significant decrease in anxiety related to breast cancer risk and were largely satisfied with their decision.⁴⁴

Prophylactic salpingo-oophorectomy

In patients who have pathogenic mutations in BRCA1 or 2, prophylactic salpingo-oophorectomy before age 40 decreases the risk of ovarian cancer by up to 96% and breast cancer by 50%.^1,37,45 This operation, in fact, is the only intervention that has been shown to reduce the mortality rate in patients with a hereditary predisposition to cancer.⁴⁶

We recommend that women with hereditary breast and ovarian cancer syndrome strongly consider prophylactic salpingo-oophorectomy by age 40 or when childbearing is complete for the greatest reduction in risk.^1,5 In 2006, Domchek et al⁴⁶ reported an overall decrease in the mortality rate in BRCA1/2-positive patients who underwent this surgery, but not in breast cancer-specific or ovarian cancer-specific mortality.

On the other hand, removing the ovaries before menopause places women at risk of serious complications associated with premature loss of gonadal hormones, including cardiovascular disease, decreased bone density, reduced sexual satisfaction, dyspareunia, hot flashes, and night sweats.⁴⁷ Therefore, it is generally reserved for women who are also at risk of ovarian cancer.

Hormonal therapy, ie, estrogen therapy for patients who choose complete hysterectomy, and estrogen-progesterone therapy for patients who choose to keep their uterus, reduces menopausal symptoms and symptoms of sexual dissatisfaction and has not thus far been shown to increase breast cancer risk.^1,34 However, this information is from nonrandomized studies, which are inherently limited.

It is important to address and modify risk factors for heart disease and osteoporosis in women with premature surgical menopause, as they may be particularly vulnerable to these conditions.

HEREDITARY BREAST CANCER IN MEN

Fewer than 1% of cases of breast cancer arise in men, and fewer than 1% of cases of cancer in men are breast cancer.

Male breast cancer is more likely than female breast cancer to be estrogen receptor- and progesterone receptor-positive. In an analysis of the Surveillance, Epidemiology, and End Results registry between 1973 and 2005, triple-negative breast cancer was found in 23% of female patients but only 7.6% of male patients.²

Male breast cancer is most common in families with BRCA2, and to a lesser degree, BRCA1 mutations. Other genetic disorders including Li-Fraumeni syndrome, hereditary nonpolyposis colorectal cancer, and Klinefelter syndrome also increase the risk of male breast cancer. A genetic predisposition for breast cancer is present in approximately 10% of male breast cancer patients.² Any man with breast cancer, therefore, should be referred for genetic counseling.

In men, a BRCA2 mutation confers a lifetime risk of breast cancer of 5% to 10%.² This is similar to the lifetime risk of breast cancer for the average woman but it is still significant, as the lifetime risk of breast cancer for the average man is 0.1%.^1,2

Five-year survival rates in male breast cancer range from only 36% to 66%, most likely because it is usually diagnosed in later stages, as men are not routinely screened for breast cancer. In men with known hereditary susceptibility, National Comprehensive Cancer Network guidelines recommend that they be educated about and begin breast self-examination at the age of 35 and be clinically examined every 12 months starting at age 35.⁴⁸ There are limited data to support breast imaging in men. High-risk surveillance with MRI screening in this group is not recommended. Prostate cancer screening is recommended for men with BRCA2 mutations starting at age 40, and should be considered for men with BRCA1 mutations starting at age 40.

No specific guidelines exist for pancreatic cancer and melanoma, but screening may be individualized based on cancers observed in the family.

A 25-year-old woman presents to the emergency department with a 7-day history of fatigue and nausea. On presentation she denies having abdominal pain, headache, fever, chills, night sweats, vomiting, diarrhea, melena, hematochezia, or weight loss. She recalls changes in the colors of her eyes and darkening urine over the last few days. Her medical history before this is unremarkable. She takes no prescription, over-the-counter, or herbal medications. She works as a librarian and has no occupational toxic exposures. She is single and has one sister with no prior medical history. She denies recent travel, sick contacts, smoking, recreational drug use, or pets at home.

On physical examination, her vital signs are temperature 37.3°C (99.1°F), heart rate 90 beats per minute, blood pressure 125/80 mm Hg, respiration rate 14 per minute, and oxygen saturation 97% on room air. She has icteric sclera and her skin is jaundiced. Cardiac examination is normal. Lungs are clear to auscultation and percussion bilaterally. Her abdomen is soft with no visceromegaly, masses, or tenderness. Extremities are normal with no edema. She is alert and oriented, but she has mild asterixis of the outstretched hands. The neurologic examination is otherwise unremarkable.

The patient’s basic laboratory values are listed in Table 1. Shortly after admission, she develops changes in her mental status, remaining alert but becoming agitated and oriented to person only. In view of her symptoms and laboratory findings, acute liver failure is suspected.

ACUTE LIVER FAILURE

1. The diagnostic criteria for acute liver failure include all of the following except which one?

• Acute elevation of liver biochemical tests
• Presence of preexisting liver disease
• Coagulopathy, defined by an international normalized ratio (INR) of 1.5 or greater
• Encephalopathy
• Duration of symptoms less than 26 weeks

Acute liver failure is defined by acute onset of worsening liver tests, coagulopathy (INR ≥ 1.5), and encephalopathy in patients with no preexisting liver disease and with symptom duration of less than 26 weeks.¹ With a few exceptions, a history of preexisting liver disease negates the diagnosis of acute liver failure. Our patient meets the diagnostic criteria for acute liver failure.

Immediate management

Once acute liver failure is identified or suspected, the next step is to transfer the patient to the intensive care unit for close monitoring of mental status. Serial neurologic evaluations permit early detection of cerebral edema, which is considered the most common cause of death in patients with acute liver failure. Additionally, close monitoring of electrolytes and plasma glucose is necessary since these patients are susceptible to electrolyte disturbances and hypoglycemia.

Patients with acute liver failure are at increased risk of infections and should be routinely screened by obtaining urine and blood cultures.

Gastrointestinal bleeding is not uncommon in patients with acute liver failure and is usually due to gastric stress ulceration. Prophylaxis with a histamine 2 receptor antagonist or proton pump inhibitor should be considered in order to prevent gastrointestinal bleeding.

Treatment with N-acetylcysteine is beneficial, not only in patients with acute liver failure due to acetaminophen overdose, but also in those with acute liver failure from other causes.

CASE CONTINUES:
TRANSFER TO THE INTENSIVE CARE UNIT

The patient, now diagnosed with acute liver failure, is transferred to the intensive care unit. Arterial blood gas measurement shows:

• pH 7.38 (reference range 7.35–7.45)
• Pco₂ 40 mm Hg (36–46)
• Po₂ 97 mm Hg (85–95)
• Hco₃ 22 mmol/L (22–26).

A chest radiograph is obtained and is clear. Computed tomography (CT) of the brain reveals no edema. Transcranial Doppler ultrasonography does not show any intracranial fluid collections.

Blood and urine cultures are negative. Her hemoglobin level remains stable, and she does not develop signs of bleeding. She is started on a proton pump inhibitor for stress ulcer prophylaxis and is empirically given intravenous N-acetylcysteine until the cause of acute liver failure can be determined.

CAUSES OF ACUTE LIVER FAILURE

2. Which of the following can cause acute liver failure?

• Acetaminophen overdose
• Viral hepatitis
• Autoimmune hepatitis
• Wilson disease
• Alcoholic hepatitis

Drug-induced liver injury is the most common cause of acute liver failure in the United States,^2,3 and of all drugs, acetaminophen overdose is the number-one cause. In acetaminophen-induced liver injury, serum aminotransferase levels are usually elevated to more than 1,000 U/L, while serum bilirubin remains normal in the early stages. Antimicrobial agents, antiepileptic drugs, and herbal supplements have also been implicated in acute liver failure. Our patient has denied taking herbal supplements or medications, including over-the-counter ones.

Acute viral hepatitis can explain the patient’s condition. It is a common cause of acute liver failure in the United States.² Hepatitis A and E are more common in developing countries. Other viruses such as cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1 and 2, and varicella zoster virus can also cause acute liver failure. Serum aminotransferase levels may exceed 1,000 U/L in patients with viral hepatitis.

A young woman presents with acute liver failure: What is the cause? Is her sister at risk?

Autoimmune hepatitis is a rare cause of acute liver failure, but it should be considered in the differential diagnosis, particularly in middle-aged women with autoimmune disorders such as hypothyroidism. Autoimmune hepatitis can cause marked elevation in aminotransferase levels (> 1,000 U/L).

Wilson disease is an autosomal-recessive disease in which there is excessive accumulation of copper in the liver and other organs because of an inherited defect in the biliary excretion of copper. Wilson disease can cause acute liver failure and should be excluded in any patient, particularly if under age 40 with acute onset of unexplained hepatic, neurologic, or psychiatric disease.

Alcoholic hepatitis usually occurs in patients with a long-standing history of heavy alcohol use. As a result, most patients with alcoholic hepatitis have manifestations of chronic liver disease due to alcohol use. Therefore, by definition, it is not a cause of acute liver failure. Additionally, in patients with alcoholic hepatitis, the aspartate aminotransferase (AST) level is elevated but less than 300 IU/mL, and the ratio of AST to alanine aminotransferase (ALT) is usually more than 2.

CASE CONTINUES: FURTHER TESTING

The results of our patient’s serologic tests are shown in Table 2. Other test results:

• Autoimmune markers including antinuclear antibodies, antimitochondrial antibodies, antismooth muscle antibodies, and liver and kidney microsomal antibodies are negative; her immunoglobulin G (IgG) level is normal
• Serum ceruloplasmin 25 mg/dL (normal 21–45)
• Free serum copper 120 µg/dL (normal 8–12)
• Abdominal ultrasonography is unremarkable, with normal liver parenchyma and no intrahepatic or extrahepatic biliary dilatation
• Doppler ultrasonography of the liver shows patent blood vessels.

3. Based on the new data, which of the following statements is correct?

• Hepatitis B is the cause of acute liver failure in this patient
• Herpetic hepatitis cannot be excluded on the basis of the available data
• Wilson disease is most likely the diagnosis, given her elevated free serum copper
• A normal serum ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease

Hepatitis B surface antigen and hepatitis B core antibodies were negative in our patient, excluding hepatitis B virus infection. The positive hepatitis B surface antibody indicates prior immunization.

Herpetic hepatitis is an uncommon but important cause of acute liver failure because the mortality rate is high if the patient is not treated early with acyclovir. Fever, elevated aminotransferases, and leukopenia are common with herpetic hepatitis. Fewer than 50% of patients with herpetic hepatitis have vesicular rash.^4,5 The value of antibody serologic testing is limited due to high rates of false-positive and false-negative results. The gold standard diagnostic tests are viral load (detection of viral RNA by polymerase chain reaction), viral staining on liver biopsy, or both. In our patient, herpes simplex virus polymerase chain reaction testing was negative, which makes herpetic hepatitis unlikely.

Wilson disease is a genetic condition in which the ability to excrete copper in the bile is impaired, resulting in accumulation of copper in the hepatocytes. Subsequently, copper is released into the bloodstream and eventually into the urine.

However, copper excretion into the bile is impaired in patients with acute liver failure regardless of the etiology. Therefore, elevated free serum copper and 24-hour urine copper levels are not specific for the diagnosis of acute liver failure secondary to Wilson disease. Moreover, Kayser-Fleischer rings, which represent copper deposition in the limbus of the cornea, may not be apparent in the early stages of Wilson disease.

Wilson disease involves accumulation of copper in the liver and other organs as the result of a genetic defect

Since it is challenging to diagnose Wilson disease in the context of acute liver failure, Korman et al⁶ compared patients with acute liver failure secondary to Wilson disease with patients with acute liver failure secondary to other conditions. They found that alkaline phosphatase levels are frequently decreased in patients with acute liver failure secondary to Wilson disease,⁶ and that a ratio of alkaline phosphatase to total bilirubin of less than 4 is 94% sensitive and 96% specific for the diagnosis.⁶

Hemolysis is common in acute liver failure due to Wilson disease. This leads to disproportionate elevation of AST compared with ALT, since AST is present in red blood cells. Consequently, the ratio of AST to ALT is usually greater than 2.2, which provides a sensitivity of 94% and a specificity of 86% for the diagnosis.⁶ These two ratios together provide 100% sensitivity and 100% specificity for the diagnosis of Wilson disease in the context of acute liver failure.⁶

Ceruloplasmin. Patients with Wilson disease typically have a low ceruloplasmin level. However, because it is an acute-phase reaction protein, ceruloplasmin can be normal or elevated in patients with acute liver failure from Wilson disease.⁶ Therefore, a normal ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease.

CASE CONTINUES: A DEFINITIVE DIAGNOSIS

Our patient undergoes further testing, which reveals the following:

• Her 24-hour urinary excretion of copper is 150 µg (reference value < 30)
• Slit-lamp examination is normal and shows no evidence of Kayser-Fleischer rings
• Her ratio of alkaline phosphatase to total bilirubin is 0.77 based on her initial laboratory results (Table 1)
• Her AST-ALT ratio is 3.4.

The diagnosis in our patient is acute liver failure secondary to Wilson disease.

4. What is the most appropriate next step?

• Liver biopsy
• d-penicillamine by mouth
• Trientine by mouth
• Liver transplant
• Plasmapheresis

Liver biopsy. Accumulation of copper in the liver parenchyma in patients with Wilson disease is sporadic. Therefore, qualitative copper staining on liver biopsy can be falsely negative. Quantitative copper measurement in liver tissue is the gold standard for the diagnosis of Wilson disease. However, the test is time-consuming and is not rapidly available in the context of acute liver failure.

Chelating agents such as d-pencillamine and trientine are used to treat the chronic manifestations of Wilson disease but are not useful for acute liver failure secondary to Wilson disease.

Acute liver failure secondary to Wilson disease is life-threatening, and liver transplant is considered the only definitive life-saving therapy.

Therapeutic plasmapheresis has been reported to be a successful adjunctive therapy to bridge patients with acute liver failure secondary to Wilson disease to transplant.⁷ However, liver transplant is still the only definitive treatment.

CASE CONTINUES: THE PATIENT’S SISTER SEEKS CARE

The patient undergoes liver transplantation, with no perioperative or postoperative complications.

The patient’s 18-year-old sister is now seeking medical attention in the outpatient clinic, concerned that she may have Wilson disease. She is otherwise healthy and denies any symptoms or complaints.

5. What is the next step for the patient’s sister?

• Reassurance
• Prophylaxis with trientine
• Check liver enzyme levels, serum ceruloplasmin level, and urine copper, and order a slit-lamp examination
• Genetic testing

Wilson disease can be asymptomatic in its early stages and may be diagnosed incidentally during routine blood tests that reveal abnormal liver enzyme levels. All patients with a confirmed family history of Wilson disease should be screened even if they are asymptomatic. The diagnosis of Wilson disease should be established in first-degree relatives before specific treatment for the relatives is prescribed.

Based on information in Roberts EA, Schilsky ML; American Association for Study of Liver Diseases (AASLD). Diagnosis and treatment of Wilson disease: an update. Hepatology 2008; 7:2089–2111.

The first step in screening a first-degree relative for Wilson disease is to check liver enzyme levels (specifically aminotransferases, alkaline phosphatase, and bilirubin), serum ceruloplasmin level, and 24-hour urine copper, and order an ophthalmologic slit-lamp examination. If any of these tests is abnormal, liver biopsy should be performed for histopathologic evaluation and quantitative copper measurement. Kayser-Fleischer  rings are seen in only 50% of patients with Wilson disease and hepatic involvement, but they are pathognomic. Guidelines⁸ for screening first-degree relatives of Wilson disease patients are shown in Figure 1.

Genetic analysis. ATP7B, the Wilson disease gene, is located on chromosome 13. At least 300 mutations of the gene have been described,² and the most common mutation is present in only 15% to 30% of the Wilson disease population.^8–10 Routine molecular testing of the ATP7B

CASE CONTINUES: WORKUP OF THE PATIENT’S SISTER

The patient’s sister has no symptoms and her physical examination is normal. Slit-lamp examination reveals no evidence of Kayser-Fleischer rings. Her laboratory values, including complete blood counts, complete metabolic panel, and INR, are within normal ranges. Other test results, however, are abnormal:

• Free serum copper level 27 µg/dL (normal 8–12)
• Serum ceruloplasmin 9.0 mg/dL (normal 20–50)
• 24-hour urinary copper excretion 135 µg (normal < 30).

She undergoes liver biopsy for quantitative copper measurement, and the result is very high at 1,118 µg/g dry weight (reference range 10–35). The diagnosis of Wilson disease is established.

TREATING CHRONIC WILSON DISEASE

6. Which of the following is not an appropriate next step for the patient’s sister?

• Tetrathiomolybdate
• d-penicillamine
• Trientine
• Zinc salts
• Prednisone

The goal of medical treatment of chronic Wilson disease is to improve symptoms and prevent progression of the disease.

Chelating agents and zinc salts are the most commonly used medicines in the management of Wilson disease. Chelating agents remove copper from tissue, whereas zinc blocks the intestinal absorption of copper and stimulates the synthesis of endogenous chelators such as metallothioneins. Tetrathiomolybdate is an alternative agent developed to interfere with the distribution of excess body copper to susceptible target sites by reducing free serum copper (Table 3). There are no data to support the use of prednisone in the treatment of Wilson disease.

During treatment with chelating agents, 24-hour urinary excretion of copper is routinely monitored to determine the efficacy of therapy and adherence to treatment. Once de-coppering is achieved, as evidenced by a normalization of 24-hour urine copper excretion, the chelating agent can be switched to zinc salts to prevent intestinal absorption of copper.

Clinical and biochemical stabilization is achieved typically within 2 to 6 months of the initial treatment with chelating agents.⁸ Organ meats, nuts, shellfish, and chocolate are rich in copper and should be avoided.

The patient’s sister is started on trientine 250 mg orally three times daily on an empty stomach at least 1 hour before meals. Treatment is monitored by following 24-hour urine copper measurement. A 24-hour urine copper measurement at 3 months after starting treatment has increased from 54 at baseline to 350 µg, which indicates that the copper is being removed from tissues. The plan is for early substitution of zinc for long-term maintenance once de-coppering is completed.

KEY POINTS

• Acute liver failure is severe acute liver injury characterized by coagulopathy (INR ≥ 1.5) and encephalopathy in a patient with no preexisting liver disease and with duration of symptoms less than 26 weeks.
• Acute liver failure secondary to Wilson disease is uncommon but should be excluded, particularly in young patients.
• The diagnosis of Wilson disease in the setting of acute liver failure is challenging because the serum ceruloplasmin level may be normal in acute liver failure secondary to Wilson disease, and free serum copper and 24-hour urine copper are usually elevated in all acute liver failure patients regardless of the etiology.
• A ratio of alkaline phosphatase to total bilirubin of less than 4 plus an AST-ALT ratio greater than 2.2 in a patient with acute liver failure should be regarded as Wilson disease until proven otherwise (Figure 2).
• Acute liver failure secondary to Wilson disease is usually fatal, and emergency liver transplant is a life-saving procedure.
• Screening of first-degree relatives of Wilson disease patients should include a history and physical examination, liver enzyme tests, complete blood cell count, serum ceruloplasmin level, serum free copper level, slit-lamp examination of the eyes, and 24-hour urinary copper measurement. Genetic tests are supplementary for screening but are not routinely available.

A 25-year-old woman presents to the emergency department with a 7-day history of fatigue and nausea. On presentation she denies having abdominal pain, headache, fever, chills, night sweats, vomiting, diarrhea, melena, hematochezia, or weight loss. She recalls changes in the colors of her eyes and darkening urine over the last few days. Her medical history before this is unremarkable. She takes no prescription, over-the-counter, or herbal medications. She works as a librarian and has no occupational toxic exposures. She is single and has one sister with no prior medical history. She denies recent travel, sick contacts, smoking, recreational drug use, or pets at home.

On physical examination, her vital signs are temperature 37.3°C (99.1°F), heart rate 90 beats per minute, blood pressure 125/80 mm Hg, respiration rate 14 per minute, and oxygen saturation 97% on room air. She has icteric sclera and her skin is jaundiced. Cardiac examination is normal. Lungs are clear to auscultation and percussion bilaterally. Her abdomen is soft with no visceromegaly, masses, or tenderness. Extremities are normal with no edema. She is alert and oriented, but she has mild asterixis of the outstretched hands. The neurologic examination is otherwise unremarkable.

The patient’s basic laboratory values are listed in Table 1. Shortly after admission, she develops changes in her mental status, remaining alert but becoming agitated and oriented to person only. In view of her symptoms and laboratory findings, acute liver failure is suspected.

ACUTE LIVER FAILURE

1. The diagnostic criteria for acute liver failure include all of the following except which one?

• Acute elevation of liver biochemical tests
• Presence of preexisting liver disease
• Coagulopathy, defined by an international normalized ratio (INR) of 1.5 or greater
• Encephalopathy
• Duration of symptoms less than 26 weeks

Acute liver failure is defined by acute onset of worsening liver tests, coagulopathy (INR ≥ 1.5), and encephalopathy in patients with no preexisting liver disease and with symptom duration of less than 26 weeks.¹ With a few exceptions, a history of preexisting liver disease negates the diagnosis of acute liver failure. Our patient meets the diagnostic criteria for acute liver failure.

Immediate management

Once acute liver failure is identified or suspected, the next step is to transfer the patient to the intensive care unit for close monitoring of mental status. Serial neurologic evaluations permit early detection of cerebral edema, which is considered the most common cause of death in patients with acute liver failure. Additionally, close monitoring of electrolytes and plasma glucose is necessary since these patients are susceptible to electrolyte disturbances and hypoglycemia.

Patients with acute liver failure are at increased risk of infections and should be routinely screened by obtaining urine and blood cultures.

Gastrointestinal bleeding is not uncommon in patients with acute liver failure and is usually due to gastric stress ulceration. Prophylaxis with a histamine 2 receptor antagonist or proton pump inhibitor should be considered in order to prevent gastrointestinal bleeding.

Treatment with N-acetylcysteine is beneficial, not only in patients with acute liver failure due to acetaminophen overdose, but also in those with acute liver failure from other causes.

CASE CONTINUES:
TRANSFER TO THE INTENSIVE CARE UNIT

The patient, now diagnosed with acute liver failure, is transferred to the intensive care unit. Arterial blood gas measurement shows:

• pH 7.38 (reference range 7.35–7.45)
• Pco₂ 40 mm Hg (36–46)
• Po₂ 97 mm Hg (85–95)
• Hco₃ 22 mmol/L (22–26).

A chest radiograph is obtained and is clear. Computed tomography (CT) of the brain reveals no edema. Transcranial Doppler ultrasonography does not show any intracranial fluid collections.

Blood and urine cultures are negative. Her hemoglobin level remains stable, and she does not develop signs of bleeding. She is started on a proton pump inhibitor for stress ulcer prophylaxis and is empirically given intravenous N-acetylcysteine until the cause of acute liver failure can be determined.

CAUSES OF ACUTE LIVER FAILURE

2. Which of the following can cause acute liver failure?

• Acetaminophen overdose
• Viral hepatitis
• Autoimmune hepatitis
• Wilson disease
• Alcoholic hepatitis

Drug-induced liver injury is the most common cause of acute liver failure in the United States,^2,3 and of all drugs, acetaminophen overdose is the number-one cause. In acetaminophen-induced liver injury, serum aminotransferase levels are usually elevated to more than 1,000 U/L, while serum bilirubin remains normal in the early stages. Antimicrobial agents, antiepileptic drugs, and herbal supplements have also been implicated in acute liver failure. Our patient has denied taking herbal supplements or medications, including over-the-counter ones.

Acute viral hepatitis can explain the patient’s condition. It is a common cause of acute liver failure in the United States.² Hepatitis A and E are more common in developing countries. Other viruses such as cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1 and 2, and varicella zoster virus can also cause acute liver failure. Serum aminotransferase levels may exceed 1,000 U/L in patients with viral hepatitis.

A young woman presents with acute liver failure: What is the cause? Is her sister at risk?

Autoimmune hepatitis is a rare cause of acute liver failure, but it should be considered in the differential diagnosis, particularly in middle-aged women with autoimmune disorders such as hypothyroidism. Autoimmune hepatitis can cause marked elevation in aminotransferase levels (> 1,000 U/L).

Wilson disease is an autosomal-recessive disease in which there is excessive accumulation of copper in the liver and other organs because of an inherited defect in the biliary excretion of copper. Wilson disease can cause acute liver failure and should be excluded in any patient, particularly if under age 40 with acute onset of unexplained hepatic, neurologic, or psychiatric disease.

Alcoholic hepatitis usually occurs in patients with a long-standing history of heavy alcohol use. As a result, most patients with alcoholic hepatitis have manifestations of chronic liver disease due to alcohol use. Therefore, by definition, it is not a cause of acute liver failure. Additionally, in patients with alcoholic hepatitis, the aspartate aminotransferase (AST) level is elevated but less than 300 IU/mL, and the ratio of AST to alanine aminotransferase (ALT) is usually more than 2.

CASE CONTINUES: FURTHER TESTING

The results of our patient’s serologic tests are shown in Table 2. Other test results:

• Autoimmune markers including antinuclear antibodies, antimitochondrial antibodies, antismooth muscle antibodies, and liver and kidney microsomal antibodies are negative; her immunoglobulin G (IgG) level is normal
• Serum ceruloplasmin 25 mg/dL (normal 21–45)
• Free serum copper 120 µg/dL (normal 8–12)
• Abdominal ultrasonography is unremarkable, with normal liver parenchyma and no intrahepatic or extrahepatic biliary dilatation
• Doppler ultrasonography of the liver shows patent blood vessels.

3. Based on the new data, which of the following statements is correct?

• Hepatitis B is the cause of acute liver failure in this patient
• Herpetic hepatitis cannot be excluded on the basis of the available data
• Wilson disease is most likely the diagnosis, given her elevated free serum copper
• A normal serum ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease

Hepatitis B surface antigen and hepatitis B core antibodies were negative in our patient, excluding hepatitis B virus infection. The positive hepatitis B surface antibody indicates prior immunization.

Herpetic hepatitis is an uncommon but important cause of acute liver failure because the mortality rate is high if the patient is not treated early with acyclovir. Fever, elevated aminotransferases, and leukopenia are common with herpetic hepatitis. Fewer than 50% of patients with herpetic hepatitis have vesicular rash.^4,5 The value of antibody serologic testing is limited due to high rates of false-positive and false-negative results. The gold standard diagnostic tests are viral load (detection of viral RNA by polymerase chain reaction), viral staining on liver biopsy, or both. In our patient, herpes simplex virus polymerase chain reaction testing was negative, which makes herpetic hepatitis unlikely.

Wilson disease is a genetic condition in which the ability to excrete copper in the bile is impaired, resulting in accumulation of copper in the hepatocytes. Subsequently, copper is released into the bloodstream and eventually into the urine.

However, copper excretion into the bile is impaired in patients with acute liver failure regardless of the etiology. Therefore, elevated free serum copper and 24-hour urine copper levels are not specific for the diagnosis of acute liver failure secondary to Wilson disease. Moreover, Kayser-Fleischer rings, which represent copper deposition in the limbus of the cornea, may not be apparent in the early stages of Wilson disease.

Wilson disease involves accumulation of copper in the liver and other organs as the result of a genetic defect

Since it is challenging to diagnose Wilson disease in the context of acute liver failure, Korman et al⁶ compared patients with acute liver failure secondary to Wilson disease with patients with acute liver failure secondary to other conditions. They found that alkaline phosphatase levels are frequently decreased in patients with acute liver failure secondary to Wilson disease,⁶ and that a ratio of alkaline phosphatase to total bilirubin of less than 4 is 94% sensitive and 96% specific for the diagnosis.⁶

Hemolysis is common in acute liver failure due to Wilson disease. This leads to disproportionate elevation of AST compared with ALT, since AST is present in red blood cells. Consequently, the ratio of AST to ALT is usually greater than 2.2, which provides a sensitivity of 94% and a specificity of 86% for the diagnosis.⁶ These two ratios together provide 100% sensitivity and 100% specificity for the diagnosis of Wilson disease in the context of acute liver failure.⁶

Ceruloplasmin. Patients with Wilson disease typically have a low ceruloplasmin level. However, because it is an acute-phase reaction protein, ceruloplasmin can be normal or elevated in patients with acute liver failure from Wilson disease.⁶ Therefore, a normal ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease.

CASE CONTINUES: A DEFINITIVE DIAGNOSIS

Our patient undergoes further testing, which reveals the following:

• Her 24-hour urinary excretion of copper is 150 µg (reference value < 30)
• Slit-lamp examination is normal and shows no evidence of Kayser-Fleischer rings
• Her ratio of alkaline phosphatase to total bilirubin is 0.77 based on her initial laboratory results (Table 1)
• Her AST-ALT ratio is 3.4.

The diagnosis in our patient is acute liver failure secondary to Wilson disease.

4. What is the most appropriate next step?

• Liver biopsy
• d-penicillamine by mouth
• Trientine by mouth
• Liver transplant
• Plasmapheresis

Liver biopsy. Accumulation of copper in the liver parenchyma in patients with Wilson disease is sporadic. Therefore, qualitative copper staining on liver biopsy can be falsely negative. Quantitative copper measurement in liver tissue is the gold standard for the diagnosis of Wilson disease. However, the test is time-consuming and is not rapidly available in the context of acute liver failure.

Chelating agents such as d-pencillamine and trientine are used to treat the chronic manifestations of Wilson disease but are not useful for acute liver failure secondary to Wilson disease.

Acute liver failure secondary to Wilson disease is life-threatening, and liver transplant is considered the only definitive life-saving therapy.

Therapeutic plasmapheresis has been reported to be a successful adjunctive therapy to bridge patients with acute liver failure secondary to Wilson disease to transplant.⁷ However, liver transplant is still the only definitive treatment.

CASE CONTINUES: THE PATIENT’S SISTER SEEKS CARE

The patient undergoes liver transplantation, with no perioperative or postoperative complications.

The patient’s 18-year-old sister is now seeking medical attention in the outpatient clinic, concerned that she may have Wilson disease. She is otherwise healthy and denies any symptoms or complaints.

5. What is the next step for the patient’s sister?

• Reassurance
• Prophylaxis with trientine
• Check liver enzyme levels, serum ceruloplasmin level, and urine copper, and order a slit-lamp examination
• Genetic testing

Wilson disease can be asymptomatic in its early stages and may be diagnosed incidentally during routine blood tests that reveal abnormal liver enzyme levels. All patients with a confirmed family history of Wilson disease should be screened even if they are asymptomatic. The diagnosis of Wilson disease should be established in first-degree relatives before specific treatment for the relatives is prescribed.

Based on information in Roberts EA, Schilsky ML; American Association for Study of Liver Diseases (AASLD). Diagnosis and treatment of Wilson disease: an update. Hepatology 2008; 7:2089–2111.

The first step in screening a first-degree relative for Wilson disease is to check liver enzyme levels (specifically aminotransferases, alkaline phosphatase, and bilirubin), serum ceruloplasmin level, and 24-hour urine copper, and order an ophthalmologic slit-lamp examination. If any of these tests is abnormal, liver biopsy should be performed for histopathologic evaluation and quantitative copper measurement. Kayser-Fleischer  rings are seen in only 50% of patients with Wilson disease and hepatic involvement, but they are pathognomic. Guidelines⁸ for screening first-degree relatives of Wilson disease patients are shown in Figure 1.

Genetic analysis. ATP7B, the Wilson disease gene, is located on chromosome 13. At least 300 mutations of the gene have been described,² and the most common mutation is present in only 15% to 30% of the Wilson disease population.^8–10 Routine molecular testing of the ATP7B

CASE CONTINUES: WORKUP OF THE PATIENT’S SISTER

The patient’s sister has no symptoms and her physical examination is normal. Slit-lamp examination reveals no evidence of Kayser-Fleischer rings. Her laboratory values, including complete blood counts, complete metabolic panel, and INR, are within normal ranges. Other test results, however, are abnormal:

• Free serum copper level 27 µg/dL (normal 8–12)
• Serum ceruloplasmin 9.0 mg/dL (normal 20–50)
• 24-hour urinary copper excretion 135 µg (normal < 30).

She undergoes liver biopsy for quantitative copper measurement, and the result is very high at 1,118 µg/g dry weight (reference range 10–35). The diagnosis of Wilson disease is established.

TREATING CHRONIC WILSON DISEASE

6. Which of the following is not an appropriate next step for the patient’s sister?

• Tetrathiomolybdate
• d-penicillamine
• Trientine
• Zinc salts
• Prednisone

The goal of medical treatment of chronic Wilson disease is to improve symptoms and prevent progression of the disease.

Chelating agents and zinc salts are the most commonly used medicines in the management of Wilson disease. Chelating agents remove copper from tissue, whereas zinc blocks the intestinal absorption of copper and stimulates the synthesis of endogenous chelators such as metallothioneins. Tetrathiomolybdate is an alternative agent developed to interfere with the distribution of excess body copper to susceptible target sites by reducing free serum copper (Table 3). There are no data to support the use of prednisone in the treatment of Wilson disease.

During treatment with chelating agents, 24-hour urinary excretion of copper is routinely monitored to determine the efficacy of therapy and adherence to treatment. Once de-coppering is achieved, as evidenced by a normalization of 24-hour urine copper excretion, the chelating agent can be switched to zinc salts to prevent intestinal absorption of copper.

Clinical and biochemical stabilization is achieved typically within 2 to 6 months of the initial treatment with chelating agents.⁸ Organ meats, nuts, shellfish, and chocolate are rich in copper and should be avoided.

The patient’s sister is started on trientine 250 mg orally three times daily on an empty stomach at least 1 hour before meals. Treatment is monitored by following 24-hour urine copper measurement. A 24-hour urine copper measurement at 3 months after starting treatment has increased from 54 at baseline to 350 µg, which indicates that the copper is being removed from tissues. The plan is for early substitution of zinc for long-term maintenance once de-coppering is completed.

KEY POINTS

• Acute liver failure is severe acute liver injury characterized by coagulopathy (INR ≥ 1.5) and encephalopathy in a patient with no preexisting liver disease and with duration of symptoms less than 26 weeks.
• Acute liver failure secondary to Wilson disease is uncommon but should be excluded, particularly in young patients.
• The diagnosis of Wilson disease in the setting of acute liver failure is challenging because the serum ceruloplasmin level may be normal in acute liver failure secondary to Wilson disease, and free serum copper and 24-hour urine copper are usually elevated in all acute liver failure patients regardless of the etiology.
• A ratio of alkaline phosphatase to total bilirubin of less than 4 plus an AST-ALT ratio greater than 2.2 in a patient with acute liver failure should be regarded as Wilson disease until proven otherwise (Figure 2).
• Acute liver failure secondary to Wilson disease is usually fatal, and emergency liver transplant is a life-saving procedure.
• Screening of first-degree relatives of Wilson disease patients should include a history and physical examination, liver enzyme tests, complete blood cell count, serum ceruloplasmin level, serum free copper level, slit-lamp examination of the eyes, and 24-hour urinary copper measurement. Genetic tests are supplementary for screening but are not routinely available.

A 25-year-old woman presents to the emergency department with a 7-day history of fatigue and nausea. On presentation she denies having abdominal pain, headache, fever, chills, night sweats, vomiting, diarrhea, melena, hematochezia, or weight loss. She recalls changes in the colors of her eyes and darkening urine over the last few days. Her medical history before this is unremarkable. She takes no prescription, over-the-counter, or herbal medications. She works as a librarian and has no occupational toxic exposures. She is single and has one sister with no prior medical history. She denies recent travel, sick contacts, smoking, recreational drug use, or pets at home.

On physical examination, her vital signs are temperature 37.3°C (99.1°F), heart rate 90 beats per minute, blood pressure 125/80 mm Hg, respiration rate 14 per minute, and oxygen saturation 97% on room air. She has icteric sclera and her skin is jaundiced. Cardiac examination is normal. Lungs are clear to auscultation and percussion bilaterally. Her abdomen is soft with no visceromegaly, masses, or tenderness. Extremities are normal with no edema. She is alert and oriented, but she has mild asterixis of the outstretched hands. The neurologic examination is otherwise unremarkable.

The patient’s basic laboratory values are listed in Table 1. Shortly after admission, she develops changes in her mental status, remaining alert but becoming agitated and oriented to person only. In view of her symptoms and laboratory findings, acute liver failure is suspected.

ACUTE LIVER FAILURE

1. The diagnostic criteria for acute liver failure include all of the following except which one?

• Acute elevation of liver biochemical tests
• Presence of preexisting liver disease
• Coagulopathy, defined by an international normalized ratio (INR) of 1.5 or greater
• Encephalopathy
• Duration of symptoms less than 26 weeks

Acute liver failure is defined by acute onset of worsening liver tests, coagulopathy (INR ≥ 1.5), and encephalopathy in patients with no preexisting liver disease and with symptom duration of less than 26 weeks.¹ With a few exceptions, a history of preexisting liver disease negates the diagnosis of acute liver failure. Our patient meets the diagnostic criteria for acute liver failure.

Immediate management

Once acute liver failure is identified or suspected, the next step is to transfer the patient to the intensive care unit for close monitoring of mental status. Serial neurologic evaluations permit early detection of cerebral edema, which is considered the most common cause of death in patients with acute liver failure. Additionally, close monitoring of electrolytes and plasma glucose is necessary since these patients are susceptible to electrolyte disturbances and hypoglycemia.

Patients with acute liver failure are at increased risk of infections and should be routinely screened by obtaining urine and blood cultures.

Gastrointestinal bleeding is not uncommon in patients with acute liver failure and is usually due to gastric stress ulceration. Prophylaxis with a histamine 2 receptor antagonist or proton pump inhibitor should be considered in order to prevent gastrointestinal bleeding.

Treatment with N-acetylcysteine is beneficial, not only in patients with acute liver failure due to acetaminophen overdose, but also in those with acute liver failure from other causes.

CASE CONTINUES:
TRANSFER TO THE INTENSIVE CARE UNIT

The patient, now diagnosed with acute liver failure, is transferred to the intensive care unit. Arterial blood gas measurement shows:

• pH 7.38 (reference range 7.35–7.45)
• Pco₂ 40 mm Hg (36–46)
• Po₂ 97 mm Hg (85–95)
• Hco₃ 22 mmol/L (22–26).

A chest radiograph is obtained and is clear. Computed tomography (CT) of the brain reveals no edema. Transcranial Doppler ultrasonography does not show any intracranial fluid collections.

Blood and urine cultures are negative. Her hemoglobin level remains stable, and she does not develop signs of bleeding. She is started on a proton pump inhibitor for stress ulcer prophylaxis and is empirically given intravenous N-acetylcysteine until the cause of acute liver failure can be determined.

CAUSES OF ACUTE LIVER FAILURE

2. Which of the following can cause acute liver failure?

• Acetaminophen overdose
• Viral hepatitis
• Autoimmune hepatitis
• Wilson disease
• Alcoholic hepatitis

Drug-induced liver injury is the most common cause of acute liver failure in the United States,^2,3 and of all drugs, acetaminophen overdose is the number-one cause. In acetaminophen-induced liver injury, serum aminotransferase levels are usually elevated to more than 1,000 U/L, while serum bilirubin remains normal in the early stages. Antimicrobial agents, antiepileptic drugs, and herbal supplements have also been implicated in acute liver failure. Our patient has denied taking herbal supplements or medications, including over-the-counter ones.

Acute viral hepatitis can explain the patient’s condition. It is a common cause of acute liver failure in the United States.² Hepatitis A and E are more common in developing countries. Other viruses such as cytomegalovirus, Epstein-Barr virus, herpes simplex virus type 1 and 2, and varicella zoster virus can also cause acute liver failure. Serum aminotransferase levels may exceed 1,000 U/L in patients with viral hepatitis.

A young woman presents with acute liver failure: What is the cause? Is her sister at risk?

Autoimmune hepatitis is a rare cause of acute liver failure, but it should be considered in the differential diagnosis, particularly in middle-aged women with autoimmune disorders such as hypothyroidism. Autoimmune hepatitis can cause marked elevation in aminotransferase levels (> 1,000 U/L).

Wilson disease is an autosomal-recessive disease in which there is excessive accumulation of copper in the liver and other organs because of an inherited defect in the biliary excretion of copper. Wilson disease can cause acute liver failure and should be excluded in any patient, particularly if under age 40 with acute onset of unexplained hepatic, neurologic, or psychiatric disease.

Alcoholic hepatitis usually occurs in patients with a long-standing history of heavy alcohol use. As a result, most patients with alcoholic hepatitis have manifestations of chronic liver disease due to alcohol use. Therefore, by definition, it is not a cause of acute liver failure. Additionally, in patients with alcoholic hepatitis, the aspartate aminotransferase (AST) level is elevated but less than 300 IU/mL, and the ratio of AST to alanine aminotransferase (ALT) is usually more than 2.

CASE CONTINUES: FURTHER TESTING

The results of our patient’s serologic tests are shown in Table 2. Other test results:

• Autoimmune markers including antinuclear antibodies, antimitochondrial antibodies, antismooth muscle antibodies, and liver and kidney microsomal antibodies are negative; her immunoglobulin G (IgG) level is normal
• Serum ceruloplasmin 25 mg/dL (normal 21–45)
• Free serum copper 120 µg/dL (normal 8–12)
• Abdominal ultrasonography is unremarkable, with normal liver parenchyma and no intrahepatic or extrahepatic biliary dilatation
• Doppler ultrasonography of the liver shows patent blood vessels.

3. Based on the new data, which of the following statements is correct?

• Hepatitis B is the cause of acute liver failure in this patient
• Herpetic hepatitis cannot be excluded on the basis of the available data
• Wilson disease is most likely the diagnosis, given her elevated free serum copper
• A normal serum ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease

Hepatitis B surface antigen and hepatitis B core antibodies were negative in our patient, excluding hepatitis B virus infection. The positive hepatitis B surface antibody indicates prior immunization.

Herpetic hepatitis is an uncommon but important cause of acute liver failure because the mortality rate is high if the patient is not treated early with acyclovir. Fever, elevated aminotransferases, and leukopenia are common with herpetic hepatitis. Fewer than 50% of patients with herpetic hepatitis have vesicular rash.^4,5 The value of antibody serologic testing is limited due to high rates of false-positive and false-negative results. The gold standard diagnostic tests are viral load (detection of viral RNA by polymerase chain reaction), viral staining on liver biopsy, or both. In our patient, herpes simplex virus polymerase chain reaction testing was negative, which makes herpetic hepatitis unlikely.

Wilson disease is a genetic condition in which the ability to excrete copper in the bile is impaired, resulting in accumulation of copper in the hepatocytes. Subsequently, copper is released into the bloodstream and eventually into the urine.

However, copper excretion into the bile is impaired in patients with acute liver failure regardless of the etiology. Therefore, elevated free serum copper and 24-hour urine copper levels are not specific for the diagnosis of acute liver failure secondary to Wilson disease. Moreover, Kayser-Fleischer rings, which represent copper deposition in the limbus of the cornea, may not be apparent in the early stages of Wilson disease.

Wilson disease involves accumulation of copper in the liver and other organs as the result of a genetic defect

Since it is challenging to diagnose Wilson disease in the context of acute liver failure, Korman et al⁶ compared patients with acute liver failure secondary to Wilson disease with patients with acute liver failure secondary to other conditions. They found that alkaline phosphatase levels are frequently decreased in patients with acute liver failure secondary to Wilson disease,⁶ and that a ratio of alkaline phosphatase to total bilirubin of less than 4 is 94% sensitive and 96% specific for the diagnosis.⁶

Hemolysis is common in acute liver failure due to Wilson disease. This leads to disproportionate elevation of AST compared with ALT, since AST is present in red blood cells. Consequently, the ratio of AST to ALT is usually greater than 2.2, which provides a sensitivity of 94% and a specificity of 86% for the diagnosis.⁶ These two ratios together provide 100% sensitivity and 100% specificity for the diagnosis of Wilson disease in the context of acute liver failure.⁶

Ceruloplasmin. Patients with Wilson disease typically have a low ceruloplasmin level. However, because it is an acute-phase reaction protein, ceruloplasmin can be normal or elevated in patients with acute liver failure from Wilson disease.⁶ Therefore, a normal ceruloplasmin level is not sufficient to rule out acute liver failure secondary to Wilson disease.

CASE CONTINUES: A DEFINITIVE DIAGNOSIS

Our patient undergoes further testing, which reveals the following:

• Her 24-hour urinary excretion of copper is 150 µg (reference value < 30)
• Slit-lamp examination is normal and shows no evidence of Kayser-Fleischer rings
• Her ratio of alkaline phosphatase to total bilirubin is 0.77 based on her initial laboratory results (Table 1)
• Her AST-ALT ratio is 3.4.

The diagnosis in our patient is acute liver failure secondary to Wilson disease.

4. What is the most appropriate next step?

• Liver biopsy
• d-penicillamine by mouth
• Trientine by mouth
• Liver transplant
• Plasmapheresis

Liver biopsy. Accumulation of copper in the liver parenchyma in patients with Wilson disease is sporadic. Therefore, qualitative copper staining on liver biopsy can be falsely negative. Quantitative copper measurement in liver tissue is the gold standard for the diagnosis of Wilson disease. However, the test is time-consuming and is not rapidly available in the context of acute liver failure.

Chelating agents such as d-pencillamine and trientine are used to treat the chronic manifestations of Wilson disease but are not useful for acute liver failure secondary to Wilson disease.

Acute liver failure secondary to Wilson disease is life-threatening, and liver transplant is considered the only definitive life-saving therapy.

Therapeutic plasmapheresis has been reported to be a successful adjunctive therapy to bridge patients with acute liver failure secondary to Wilson disease to transplant.⁷ However, liver transplant is still the only definitive treatment.

CASE CONTINUES: THE PATIENT’S SISTER SEEKS CARE

The patient undergoes liver transplantation, with no perioperative or postoperative complications.

The patient’s 18-year-old sister is now seeking medical attention in the outpatient clinic, concerned that she may have Wilson disease. She is otherwise healthy and denies any symptoms or complaints.

5. What is the next step for the patient’s sister?

• Reassurance
• Prophylaxis with trientine
• Check liver enzyme levels, serum ceruloplasmin level, and urine copper, and order a slit-lamp examination
• Genetic testing

Wilson disease can be asymptomatic in its early stages and may be diagnosed incidentally during routine blood tests that reveal abnormal liver enzyme levels. All patients with a confirmed family history of Wilson disease should be screened even if they are asymptomatic. The diagnosis of Wilson disease should be established in first-degree relatives before specific treatment for the relatives is prescribed.

Based on information in Roberts EA, Schilsky ML; American Association for Study of Liver Diseases (AASLD). Diagnosis and treatment of Wilson disease: an update. Hepatology 2008; 7:2089–2111.

The first step in screening a first-degree relative for Wilson disease is to check liver enzyme levels (specifically aminotransferases, alkaline phosphatase, and bilirubin), serum ceruloplasmin level, and 24-hour urine copper, and order an ophthalmologic slit-lamp examination. If any of these tests is abnormal, liver biopsy should be performed for histopathologic evaluation and quantitative copper measurement. Kayser-Fleischer  rings are seen in only 50% of patients with Wilson disease and hepatic involvement, but they are pathognomic. Guidelines⁸ for screening first-degree relatives of Wilson disease patients are shown in Figure 1.

Genetic analysis. ATP7B, the Wilson disease gene, is located on chromosome 13. At least 300 mutations of the gene have been described,² and the most common mutation is present in only 15% to 30% of the Wilson disease population.^8–10 Routine molecular testing of the ATP7B

CASE CONTINUES: WORKUP OF THE PATIENT’S SISTER

The patient’s sister has no symptoms and her physical examination is normal. Slit-lamp examination reveals no evidence of Kayser-Fleischer rings. Her laboratory values, including complete blood counts, complete metabolic panel, and INR, are within normal ranges. Other test results, however, are abnormal:

• Free serum copper level 27 µg/dL (normal 8–12)
• Serum ceruloplasmin 9.0 mg/dL (normal 20–50)
• 24-hour urinary copper excretion 135 µg (normal < 30).

She undergoes liver biopsy for quantitative copper measurement, and the result is very high at 1,118 µg/g dry weight (reference range 10–35). The diagnosis of Wilson disease is established.

TREATING CHRONIC WILSON DISEASE

6. Which of the following is not an appropriate next step for the patient’s sister?

• Tetrathiomolybdate
• d-penicillamine
• Trientine
• Zinc salts
• Prednisone

The goal of medical treatment of chronic Wilson disease is to improve symptoms and prevent progression of the disease.

Chelating agents and zinc salts are the most commonly used medicines in the management of Wilson disease. Chelating agents remove copper from tissue, whereas zinc blocks the intestinal absorption of copper and stimulates the synthesis of endogenous chelators such as metallothioneins. Tetrathiomolybdate is an alternative agent developed to interfere with the distribution of excess body copper to susceptible target sites by reducing free serum copper (Table 3). There are no data to support the use of prednisone in the treatment of Wilson disease.

During treatment with chelating agents, 24-hour urinary excretion of copper is routinely monitored to determine the efficacy of therapy and adherence to treatment. Once de-coppering is achieved, as evidenced by a normalization of 24-hour urine copper excretion, the chelating agent can be switched to zinc salts to prevent intestinal absorption of copper.

Clinical and biochemical stabilization is achieved typically within 2 to 6 months of the initial treatment with chelating agents.⁸ Organ meats, nuts, shellfish, and chocolate are rich in copper and should be avoided.

The patient’s sister is started on trientine 250 mg orally three times daily on an empty stomach at least 1 hour before meals. Treatment is monitored by following 24-hour urine copper measurement. A 24-hour urine copper measurement at 3 months after starting treatment has increased from 54 at baseline to 350 µg, which indicates that the copper is being removed from tissues. The plan is for early substitution of zinc for long-term maintenance once de-coppering is completed.

KEY POINTS

• Acute liver failure is severe acute liver injury characterized by coagulopathy (INR ≥ 1.5) and encephalopathy in a patient with no preexisting liver disease and with duration of symptoms less than 26 weeks.
• Acute liver failure secondary to Wilson disease is uncommon but should be excluded, particularly in young patients.
• The diagnosis of Wilson disease in the setting of acute liver failure is challenging because the serum ceruloplasmin level may be normal in acute liver failure secondary to Wilson disease, and free serum copper and 24-hour urine copper are usually elevated in all acute liver failure patients regardless of the etiology.
• A ratio of alkaline phosphatase to total bilirubin of less than 4 plus an AST-ALT ratio greater than 2.2 in a patient with acute liver failure should be regarded as Wilson disease until proven otherwise (Figure 2).
• Acute liver failure secondary to Wilson disease is usually fatal, and emergency liver transplant is a life-saving procedure.
• Screening of first-degree relatives of Wilson disease patients should include a history and physical examination, liver enzyme tests, complete blood cell count, serum ceruloplasmin level, serum free copper level, slit-lamp examination of the eyes, and 24-hour urinary copper measurement. Genetic tests are supplementary for screening but are not routinely available.

To the Editor: We previously addressed whether VKORC1 and CYP2C9 pharmacogenomic testing should be considered when prescribing warfarin.¹ Our recommendation, based on available evidence at that time, was that physicians should consider pharmacogenomic testing for any patient who is started on warfarin therapy.

Since the publication of this recommendation, two major trials, COAG (Clarification of Optimal Anticoagulation Through Genetics)² and EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin),³ were published along with commentaries debating the clinical utility of warfarin pharmacogenomics.^4–15 Based on these publications, we would like to update our recommendations for pharmacogenomic testing for warfarin therapy.

COAG compared the efficacy of a clinical algorithm or a clinical algorithm plus VKORC1 and CYP2C9 genotyping to guide warfarin dosage. At the end of 4 weeks, the mean percentage of time within the therapeutic international normalized ratio (INR) range was 45.4% for those in the clinical algorithm arm and 45.2% for those in the genotyping arm (95% confidence interval [CI] –3.4 to 3.1, P = .91). For both treatment groups, clinical data that included body surface area, age, target INR, concomitantly prescribed drugs, and smoking status were used to predict warfarin dose, with the genotyping arm including VKORC1 and CYP2C9. Although VKORC1 and CYP2C9 genotyping offered no additional benefit, caution should be used when extrapolating this conclusion to clinical settings in which warfarin therapy is initiated using a standardized starting dose (eg, 5 mg daily) instead of a clinical dosing algorithm.

Of interest, in the COAG trial, among black patients, the mean percentage of time in the therapeutic INR range was significantly less for those in the genotype-guided arm than for those in the clinically guided arm—ie, 35.2% vs 43.5% (95% CI –15.0 to –2.0, P = .01). The percentage of time with therapeutic INR has been identified as a surrogate marker for poor outcomes such as death, stroke, or major hemorrhage, with those with a lower percentage of time in therapeutic INR being at greater risk of an adverse event.¹⁶ Wan et al¹⁷ demonstrated that a 6.9% improvement of time in therapeutic INR decreased the risk of major hemorrhage by one event per 100 patient-years.¹⁷ Therefore, black patients in the COAG genotyping arm may have been at greater risk for an adverse event because of a lower observed percentage of time within the therapeutic INR range.

In the COAG trial, genotyping was done for only one VKORC1 variant and for two CYP2C9 alleles (CYP2C9*2, and CYP2C9*3). Other genetic variants are of clinical importance for warfarin dosing in black patients, and the lack of genotyping for these additional variants may explain why black patients in the genotyping arm performed worse.^5,7,11 In particular, CYP2C9*8 may be an important predictor of warfarin dose in black patients.¹⁸

EU-PACT compared the efficacy of standardized warfarin dosing and that of a clinical algorithm.³ Patients in the standardized dosing arm were prescribed warfarin 10 mg on the first day of treatment (5 mg for those over age 75), and 5 mg on days 2 and 3, with subsequent dosing adjustments based on INR. Patients in the genotyping arm were prescribed warfarin based on an algorithm that incorporated clinical data that included body surface area, age, and concomitantly prescribed drugs, as well as VKORC1 and CYP2C9 genotypes. At the end of 12 weeks, the mean percentage of time in the therapeutic INR range was 60.3% for those in the standardized-dosing arm and 67.4% for those in the genotyping arm (95% CI 3.3 to 10.6, P < .001).² The approximate 7% improvement in percentage of time in the therapeutic INR range may predict a lower risk of hemorrhage for those in the genotyping arm.¹⁷ Although patients in the genotyping arm had a higher percentage of time in the therapeutic INR range, it is unclear whether genotyping alone is superior to standardized dosing because the dosing algorithm used both clinical data and genotype data.

There are substantial differences between the COAG and EU-PACT trials, including dosing schemes, racial diversity, and trial length, and these differences could have contributed to the conflicting results. Based on these two trials, a possible conclusion is that genotype-guided warfarin dosing may be superior to standardized dosing, but may be no better than utilizing a clinical algorithm in white patients. For black patients, additional studies are needed to determine which genetic variants are of importance for guiding warfarin dosing.

We would like to update the recommendations we made in our previously published article,¹ to state that genotyping for CYP2C9 and VKORC1 may be of clinical utility in white patients depending on whether standardized dosing or a clinical algorithm is used to initiate warfarin therapy. Routine genotyping in black patients is not recommended until further studies clarify which genetic variants are of importance for guiding warfarin dosing.

The ongoing Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis may bring much needed clarity to the clinical utility of warfarin pharmacogenomics. We hope to publish a more detailed update of our 2013 article after completion of that trial.

To the Editor: We previously addressed whether VKORC1 and CYP2C9 pharmacogenomic testing should be considered when prescribing warfarin.¹ Our recommendation, based on available evidence at that time, was that physicians should consider pharmacogenomic testing for any patient who is started on warfarin therapy.

Since the publication of this recommendation, two major trials, COAG (Clarification of Optimal Anticoagulation Through Genetics)² and EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin),³ were published along with commentaries debating the clinical utility of warfarin pharmacogenomics.^4–15 Based on these publications, we would like to update our recommendations for pharmacogenomic testing for warfarin therapy.

COAG compared the efficacy of a clinical algorithm or a clinical algorithm plus VKORC1 and CYP2C9 genotyping to guide warfarin dosage. At the end of 4 weeks, the mean percentage of time within the therapeutic international normalized ratio (INR) range was 45.4% for those in the clinical algorithm arm and 45.2% for those in the genotyping arm (95% confidence interval [CI] –3.4 to 3.1, P = .91). For both treatment groups, clinical data that included body surface area, age, target INR, concomitantly prescribed drugs, and smoking status were used to predict warfarin dose, with the genotyping arm including VKORC1 and CYP2C9. Although VKORC1 and CYP2C9 genotyping offered no additional benefit, caution should be used when extrapolating this conclusion to clinical settings in which warfarin therapy is initiated using a standardized starting dose (eg, 5 mg daily) instead of a clinical dosing algorithm.

Of interest, in the COAG trial, among black patients, the mean percentage of time in the therapeutic INR range was significantly less for those in the genotype-guided arm than for those in the clinically guided arm—ie, 35.2% vs 43.5% (95% CI –15.0 to –2.0, P = .01). The percentage of time with therapeutic INR has been identified as a surrogate marker for poor outcomes such as death, stroke, or major hemorrhage, with those with a lower percentage of time in therapeutic INR being at greater risk of an adverse event.¹⁶ Wan et al¹⁷ demonstrated that a 6.9% improvement of time in therapeutic INR decreased the risk of major hemorrhage by one event per 100 patient-years.¹⁷ Therefore, black patients in the COAG genotyping arm may have been at greater risk for an adverse event because of a lower observed percentage of time within the therapeutic INR range.

In the COAG trial, genotyping was done for only one VKORC1 variant and for two CYP2C9 alleles (CYP2C9*2, and CYP2C9*3). Other genetic variants are of clinical importance for warfarin dosing in black patients, and the lack of genotyping for these additional variants may explain why black patients in the genotyping arm performed worse.^5,7,11 In particular, CYP2C9*8 may be an important predictor of warfarin dose in black patients.¹⁸

EU-PACT compared the efficacy of standardized warfarin dosing and that of a clinical algorithm.³ Patients in the standardized dosing arm were prescribed warfarin 10 mg on the first day of treatment (5 mg for those over age 75), and 5 mg on days 2 and 3, with subsequent dosing adjustments based on INR. Patients in the genotyping arm were prescribed warfarin based on an algorithm that incorporated clinical data that included body surface area, age, and concomitantly prescribed drugs, as well as VKORC1 and CYP2C9 genotypes. At the end of 12 weeks, the mean percentage of time in the therapeutic INR range was 60.3% for those in the standardized-dosing arm and 67.4% for those in the genotyping arm (95% CI 3.3 to 10.6, P < .001).² The approximate 7% improvement in percentage of time in the therapeutic INR range may predict a lower risk of hemorrhage for those in the genotyping arm.¹⁷ Although patients in the genotyping arm had a higher percentage of time in the therapeutic INR range, it is unclear whether genotyping alone is superior to standardized dosing because the dosing algorithm used both clinical data and genotype data.

There are substantial differences between the COAG and EU-PACT trials, including dosing schemes, racial diversity, and trial length, and these differences could have contributed to the conflicting results. Based on these two trials, a possible conclusion is that genotype-guided warfarin dosing may be superior to standardized dosing, but may be no better than utilizing a clinical algorithm in white patients. For black patients, additional studies are needed to determine which genetic variants are of importance for guiding warfarin dosing.

We would like to update the recommendations we made in our previously published article,¹ to state that genotyping for CYP2C9 and VKORC1 may be of clinical utility in white patients depending on whether standardized dosing or a clinical algorithm is used to initiate warfarin therapy. Routine genotyping in black patients is not recommended until further studies clarify which genetic variants are of importance for guiding warfarin dosing.

The ongoing Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis may bring much needed clarity to the clinical utility of warfarin pharmacogenomics. We hope to publish a more detailed update of our 2013 article after completion of that trial.

To the Editor: We previously addressed whether VKORC1 and CYP2C9 pharmacogenomic testing should be considered when prescribing warfarin.¹ Our recommendation, based on available evidence at that time, was that physicians should consider pharmacogenomic testing for any patient who is started on warfarin therapy.

Since the publication of this recommendation, two major trials, COAG (Clarification of Optimal Anticoagulation Through Genetics)² and EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin),³ were published along with commentaries debating the clinical utility of warfarin pharmacogenomics.^4–15 Based on these publications, we would like to update our recommendations for pharmacogenomic testing for warfarin therapy.

COAG compared the efficacy of a clinical algorithm or a clinical algorithm plus VKORC1 and CYP2C9 genotyping to guide warfarin dosage. At the end of 4 weeks, the mean percentage of time within the therapeutic international normalized ratio (INR) range was 45.4% for those in the clinical algorithm arm and 45.2% for those in the genotyping arm (95% confidence interval [CI] –3.4 to 3.1, P = .91). For both treatment groups, clinical data that included body surface area, age, target INR, concomitantly prescribed drugs, and smoking status were used to predict warfarin dose, with the genotyping arm including VKORC1 and CYP2C9. Although VKORC1 and CYP2C9 genotyping offered no additional benefit, caution should be used when extrapolating this conclusion to clinical settings in which warfarin therapy is initiated using a standardized starting dose (eg, 5 mg daily) instead of a clinical dosing algorithm.

Of interest, in the COAG trial, among black patients, the mean percentage of time in the therapeutic INR range was significantly less for those in the genotype-guided arm than for those in the clinically guided arm—ie, 35.2% vs 43.5% (95% CI –15.0 to –2.0, P = .01). The percentage of time with therapeutic INR has been identified as a surrogate marker for poor outcomes such as death, stroke, or major hemorrhage, with those with a lower percentage of time in therapeutic INR being at greater risk of an adverse event.¹⁶ Wan et al¹⁷ demonstrated that a 6.9% improvement of time in therapeutic INR decreased the risk of major hemorrhage by one event per 100 patient-years.¹⁷ Therefore, black patients in the COAG genotyping arm may have been at greater risk for an adverse event because of a lower observed percentage of time within the therapeutic INR range.

In the COAG trial, genotyping was done for only one VKORC1 variant and for two CYP2C9 alleles (CYP2C9*2, and CYP2C9*3). Other genetic variants are of clinical importance for warfarin dosing in black patients, and the lack of genotyping for these additional variants may explain why black patients in the genotyping arm performed worse.^5,7,11 In particular, CYP2C9*8 may be an important predictor of warfarin dose in black patients.¹⁸

EU-PACT compared the efficacy of standardized warfarin dosing and that of a clinical algorithm.³ Patients in the standardized dosing arm were prescribed warfarin 10 mg on the first day of treatment (5 mg for those over age 75), and 5 mg on days 2 and 3, with subsequent dosing adjustments based on INR. Patients in the genotyping arm were prescribed warfarin based on an algorithm that incorporated clinical data that included body surface area, age, and concomitantly prescribed drugs, as well as VKORC1 and CYP2C9 genotypes. At the end of 12 weeks, the mean percentage of time in the therapeutic INR range was 60.3% for those in the standardized-dosing arm and 67.4% for those in the genotyping arm (95% CI 3.3 to 10.6, P < .001).² The approximate 7% improvement in percentage of time in the therapeutic INR range may predict a lower risk of hemorrhage for those in the genotyping arm.¹⁷ Although patients in the genotyping arm had a higher percentage of time in the therapeutic INR range, it is unclear whether genotyping alone is superior to standardized dosing because the dosing algorithm used both clinical data and genotype data.

There are substantial differences between the COAG and EU-PACT trials, including dosing schemes, racial diversity, and trial length, and these differences could have contributed to the conflicting results. Based on these two trials, a possible conclusion is that genotype-guided warfarin dosing may be superior to standardized dosing, but may be no better than utilizing a clinical algorithm in white patients. For black patients, additional studies are needed to determine which genetic variants are of importance for guiding warfarin dosing.

We would like to update the recommendations we made in our previously published article,¹ to state that genotyping for CYP2C9 and VKORC1 may be of clinical utility in white patients depending on whether standardized dosing or a clinical algorithm is used to initiate warfarin therapy. Routine genotyping in black patients is not recommended until further studies clarify which genetic variants are of importance for guiding warfarin dosing.

The ongoing Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis may bring much needed clarity to the clinical utility of warfarin pharmacogenomics. We hope to publish a more detailed update of our 2013 article after completion of that trial.

“Change is the only constant.”

—Heraclitus (c 535–475 bce)

With the cost of health care rising and money to pay for it shrinking, there has never been a greater need to reduce waste.

See related article

Ineffective treatments and adverse drug effects account for much preventable morbidity and expense. New treatments, touted as more potent, are often introduced as replacements for traditional ones that are still effective in many patients, adding to costs and the potential for harm. For the pharmaceutical industry, the search for new “blockbuster” drugs seems to have hit a wall, at least in cardiovascular medicine.¹ Advances often come at the cost of adverse effects, such as bleeding with triple antiplatelet therapy and diabetes with potent statin drugs.

The path to maximizing benefit and reducing harm now appears to lie in stratifying populations and appreciating patient individuality in response to treatment. For many decades we have known that patients vary widely in their response to drugs, owing to personal factors such as body surface area, age, environment, and genetics. And indeed, we treat our patients as individuals, for example by tailoring aminoglycoside dose to weight and renal function.

However, clinical trials typically give us an idea of the benefits only to the average patient. While subgroup analyses identify groups that may benefit more or less from treatment, the additional information they provide is not easily integrated into the clinical model of prescribing, in which one size fits all.

THE PROMISE OF PHARMACOGENETICS

The emerging field of pharmacogenetics promises to give clinicians the tools to make informed treatment decisions based on predictive genetic testing. This genetic testing aims to match treatment to an individual’s genetic profile. This often involves analyzing single-nucleotide polymorphisms in genes for enzymes that metabolize drugs, such as the cytochrome P450 enzymes, to predict efficacy or an adverse event with treatment.

Pharmacogenetics is playing an increasing role in clinical trials, particularly in the early stages of drug development, by helping to reduce the number of patients needed, prove efficacy, and identify subgroups in which alternative treatment can be targeted. At another level, a molecular understanding of disease is leading to truly targeted treatments based on genomics.

Over recent years, genetic testing has been increasingly used in clinical practice, thanks to a convergence of factors such as rapid, low-cost tests, a growing evidence base, and emerging interest among doctors and payers.

An advantage to using genetic testing as opposed to other types of laboratory testing, such as measuring the concentration of the drug in the blood during treatment, is that genetic tests can predict the response to treatment before the treatment is started. Moreover, with therapeutic drug monitoring after treatment has begun, there are sometimes no detectable measures of toxicity. For example, both carbamazepine and the antiviral drug abacavir can—fortunately only rarely—cause Stevens-Johnson syndrome. But before genetic markers were discovered, there was no method of estimating this risk apart from taking a family history.^2,3 Considering the numbers of people involved, it was not feasible until recently to suggest genetic screening for patients starting on these drugs. However, the cost of genotyping and gene sequencing has been falling at a rate inversely faster than Moore’s law (an approximate annual doubling in computer power), and population genomics is becoming a reality.⁴

The US Food and Drug Administration (FDA) recognizes the current and future value of pharmacogenetics in drug safety and development. A number of approved pharmacogenetic biomarkers are listed on the FDA website (Table 1). Black box warnings have been mandated for a number of drugs on the basis of observational evidence.

The FDA also promotes rapid approval for novel drugs with pharmacogenetic “companion diagnostics.” A recent example of this was the approval of ivacaftor for cystic fibrosis patients who have the G551D mutation.⁵ Here, a molecular understanding of the condition led to the development of a targeted treatment. Although the cost of developing this drug was high, the path is now paved for similar advances. Oncologists are familiar with these advances with the emergence of new molecularly targeted treatments, eg, BRAF inhibitors in metastatic melanoma, imatinib in chronic myeloid leukemia, and gefitinib in non-small-cell lung cancer.

PHARMACOGENETICS IN CARDIOVASCULAR MEDICINE

Cardiovascular medicine also stands to benefit from rapid advances in pharmacogenetics.

While no treatment has been developed that targets the molecular basis of cardiovascular disease, a number of genomic biomarkers have emerged that identify patients at risk of adverse reactions or treatment failure. These include genetic tests to predict the maintenance dose and risk of bleeding with warfarin,⁶ the likelihood of myopathy and myositis with simvastatin,⁷ and the risk of recurrent thrombotic events with clopidogrel.^8–10

Using pharmacogenetics in prescribing warfarin and its alternatives

The pharmacogenetics of warfarin has been extensively researched, but genotyping before prescribing this drug is not yet widely done.

In 2007, the FDA updated the labeling of warfarin to include information about the influence of two genes, VKORC1 and CYP2C9, on a patient’s response to this drug. In 2010 this was updated to add that testing for these genes could be used to predict the maintenance dose of the drug. Difficulties with algorithms used to integrate this into clinical practice have hindered adoption of this testing.

With the advent of new anticoagulants such as dabigatran, rivaroxaban, and apixaban, many have expected warfarin and its pharmacogenetics to become obsolete. However, the new agents cost considerably more. Further, they may not offer a very great advantage over warfarin: in the Randomized Evaluation of Long-term Anticoagulant Therapy (RE-LY) trial, the absolute risk reduction in intracranial hemorrhage with dabigatran vs warfarin was small.¹¹ Therefore, dabigatran is probably not cost-effective in populations at low risk of bleeding.¹² A cost-effectiveness analysis comparing warfarin with dabigatran in patients with uncomplicated atrial fibrillation has suggested that dabigatran is, however, cost-effective in patients at moderate risk.¹²

In the RE-LY trial, the international normalized ratios (INRs) of the patients in the warfarin group were in the therapeutic range only 64% of the time. The advantages of dabigatran over warfarin become less pronounced as warfarin control is tightened.¹³ Of note, pharmacogenetics and home monitoring of the INR have both been shown to lead to tighter control of the INR, with greater time within the therapeutic range.^14,15

Moreover, genetic testing can help us reduce the number of bleeding events in patients taking warfarin.¹⁶ Patients who carry the CYP2C9*2 or CYP2C9*3 polymorphism metabolize S-warfarin slower and therefore have a threefold higher risk of hemorrhage after starting warfarin.¹⁷ We could speculate that patients carrying these variants may be better served by the newer anticoagulants, though this has not been tested in any clinical trial.

It is also worth appreciating that the conditions requiring anticoagulation, such as atrial fibrillation, also have a strong genetic basis. Variants in chromosomes 4q25, 1q21, and 16q22 have all been associated with atrial fibrillation.¹⁸ The risk of atrial fibrillation is five to six times higher in carriers of multiple variants within all of these loci.¹⁹ Genetic variants at 4q25 have been associated with the response to specific antiarrhythmic drug treatments,²⁰ response to pulmonary vein isolation, ^21,22 and direct-current cardioversion.²³ One can imagine a future in which patients with palpitations, carrying multiple gene risk variants, will choose prolonged monitoring at home to confirm a diagnosis. They would then be provided with a personalized best management strategy, using their personal preferences, clinical data, and genetic profile to make a treatment decision.

Using pharmacogenetics in prescribing clopidogrel and its alternatives

The pharmacogenetics of clopidogrel is of particular interest, as it has the potential of establishing a rational basis for using newer antiplatelet drugs such as ticagrelor and prasugrel, which are considerably more expensive than generic clopidogrel.

Most of the people who do not respond to clopidogrel carry the common cytochrome P450 2C19 variants CYP2C19*2 or CYP2C19*3.⁹ These variants are present in particularly high frequency in Asians and African Americans, who often do not feature in large randomized trials.

Newer antiplatelet agents have failed to demonstrate consistent superiority to clopidogrel without a tradeoff of more bleeding. However, in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 39 (TRITON TIMI-38),^24,25 patients with the *2 variant receiving prasugrel had lower cardiovascular event rates than *2 carriers receiving clopidogrel.

Similarly, the patients who benefit the most from ticagrelor are carriers of the 2C19 nonresponder variants. In a large study, clopidogrel responders who did not carry either 2C19 nonresponder genetic variants or ABCB1 variants had cardiovascular outcomes similar to those of patients receiving ticagrelor.²⁶

Clinicians have been cautious in prescribing potent antiplatelet agents to all patients because of the risk of bleeding. One could assume that by reserving newer agents for clopidogrel nonresponders, the bleeding risk could be minimized and overall benefit could be preserved with this strategy.

Cost may also be contained. The cost-effectiveness of such an approach with prasugrel has been tested with computer modeling and appears favorable.²⁷ On the other hand, a similar yet limited analysis did not find genotype-driven use of ticagrelor to be cost-effective.²⁸ This was mostly due to fewer deaths in patients receiving ticagrelor. However, the cost estimate for genotype-guided therapy was overestimated, as heterozygotes in the model were treated with ticagrelor instead of a high dose of clopidogrel.

It now appears that heterozygotes, ie, patients with one copy of the nonresponder variant, can achieve similar platelet inhibition with clopidogrel 225 mg daily as noncarriers on 75 mg daily.²⁹ Since genotype-guided antiplatelet therapy has not been tested in a randomized outcomes trial, this tailored strategy has not been widely accepted.

THE FUTURE

The barriers to adoption of pharmacogenetics are considerable. Clinicians need to be educated about it, reimbursement needs to be worked out, and the pharmaceutical industry needs to get behind it. Nevertheless, the future of pharmacogenetics is extremely promising.

Research networks are forming to support the use of pharmacogenetics in clinical practice. The Pharmgkb (www.pharmgkb.org) database serves as a hub for educating clinicians and researchers as well as curating data for reference. Vanderbilt University is piloting the BioVu project, in which DNA and genotype data on patients are being stored and matched to the electronic clinical records.³⁰ These projects not only provide clinically useful information on the current state of the art of pharmacogenetics, they also aid in disseminating new information about genotype-phenotype relationships.

Analytical software that uses “natural language processing” is being applied to clinician-generated notes to derive new observations and associations between genetic variants and clinical phenotypes. Integrating this information in real-time decision-support modules in the electronic health record provides a feedback loop for a rapid assimilation of new knowledge. Similar innovative decision-support modules are being established by Cleveland Clinic’s Center for Personalized Healthcare.³¹

The rise of ‘omic’ sciences

Pharmacogenetics and pharmacogenomics are part of a larger set of “omic” sciences. The suffix “-omics” implies a larger, more holistic view and is being applied to a number of fields—for example, the study of proteins (proteomics) and the study of metabolites (metabolomics). Profiling proteins and metabolites delivers a deluge of information on a patient that can be clustered, using pattern-recognition software, into population subgroups. Patterns of multiple proteins or metabolites are extracted from this spectral data to identify disease or response to treatment (pharmacometabolomics).

Metabolomics has been shown to predict the response to statins,³² diagnose myocardial infarction,³³ and reclassify cardiovascular risk status.³⁴ In addition, whereas traditional laboratory chemistry is reductionist, using single biomarkers for single-disease diagnosis, omic technologies hold the potential to reveal information on a number of possible health or disease states. The identification of “healthy” profiles using these technologies can potentially provide positive feedback to patients undertaking lifestyle changes and treatment.

The instrument costs for proteomic and metabolomic profiling are relatively high. However, the ongoing running costs are minimal, estimated at as low as less than $13 per test, as there are no expensive reagents.³³ High-volume testing therefore becomes very cost-effective.

Although omic science appears futuristic, proteomics and metabolomics are already used in many clinical laboratories to rapidly identify bacteria. These methods have already revolutionized the way laboratories identify microbes, since they are automated, reduce workload, and give very fast results.

The cost of genetic testing is falling

Critics of pharmacogenetics claim that the predictive value of genetic testing is poor, that evidence is lacking, and that the cost is too high. In all new technologies, the first iteration is coarse, but performance improves with use. The first major barrier is adoption. Projects like BioVu are establishing the infrastructure for a feedback loop to iteratively improve upon the status quo and provide the evidence base clinicians demand.

The cost of genetic testing is falling rapidly, with whole-genome sequencing and annotation now costing less than $5,000. The cost of a pharmacogenetic test can be as low as $100 using low-cost nanotechnology, and the test needs to be performed only once in a patient’s lifetime.²⁷

As other related molecular technologies such as proteomics and metabolomics become available and are integrated with genomics, the predictive ability of this science will improve.

AWAY FROM ONE-SIZE-FITS-ALL MEDICINE

Over the last decade there has been a trend away from “one size fits all” to customized “markets of one” in everything from consumer products to education to medicine. Mass customizing, also known as personalization, has been embraced by the internet community as a means to increase efficiency and reduce cost. This occurs by eliminating waste in redundant work or production of ineffective products.

Personalization on the Internet has been enabled through the use of informatics, mathematics, and supercomputing. The same tools that have personalized the delivery of consumer products are also being applied to the field of pharmacogenetics. Applied in an evidence-based fashion, these new technologies should profoundly improve patient care now and in the future.

“Change is the only constant.”

—Heraclitus (c 535–475 bce)

With the cost of health care rising and money to pay for it shrinking, there has never been a greater need to reduce waste.

See related article

Ineffective treatments and adverse drug effects account for much preventable morbidity and expense. New treatments, touted as more potent, are often introduced as replacements for traditional ones that are still effective in many patients, adding to costs and the potential for harm. For the pharmaceutical industry, the search for new “blockbuster” drugs seems to have hit a wall, at least in cardiovascular medicine.¹ Advances often come at the cost of adverse effects, such as bleeding with triple antiplatelet therapy and diabetes with potent statin drugs.

The path to maximizing benefit and reducing harm now appears to lie in stratifying populations and appreciating patient individuality in response to treatment. For many decades we have known that patients vary widely in their response to drugs, owing to personal factors such as body surface area, age, environment, and genetics. And indeed, we treat our patients as individuals, for example by tailoring aminoglycoside dose to weight and renal function.

However, clinical trials typically give us an idea of the benefits only to the average patient. While subgroup analyses identify groups that may benefit more or less from treatment, the additional information they provide is not easily integrated into the clinical model of prescribing, in which one size fits all.

THE PROMISE OF PHARMACOGENETICS

The emerging field of pharmacogenetics promises to give clinicians the tools to make informed treatment decisions based on predictive genetic testing. This genetic testing aims to match treatment to an individual’s genetic profile. This often involves analyzing single-nucleotide polymorphisms in genes for enzymes that metabolize drugs, such as the cytochrome P450 enzymes, to predict efficacy or an adverse event with treatment.

Pharmacogenetics is playing an increasing role in clinical trials, particularly in the early stages of drug development, by helping to reduce the number of patients needed, prove efficacy, and identify subgroups in which alternative treatment can be targeted. At another level, a molecular understanding of disease is leading to truly targeted treatments based on genomics.

Over recent years, genetic testing has been increasingly used in clinical practice, thanks to a convergence of factors such as rapid, low-cost tests, a growing evidence base, and emerging interest among doctors and payers.

An advantage to using genetic testing as opposed to other types of laboratory testing, such as measuring the concentration of the drug in the blood during treatment, is that genetic tests can predict the response to treatment before the treatment is started. Moreover, with therapeutic drug monitoring after treatment has begun, there are sometimes no detectable measures of toxicity. For example, both carbamazepine and the antiviral drug abacavir can—fortunately only rarely—cause Stevens-Johnson syndrome. But before genetic markers were discovered, there was no method of estimating this risk apart from taking a family history.^2,3 Considering the numbers of people involved, it was not feasible until recently to suggest genetic screening for patients starting on these drugs. However, the cost of genotyping and gene sequencing has been falling at a rate inversely faster than Moore’s law (an approximate annual doubling in computer power), and population genomics is becoming a reality.⁴

The US Food and Drug Administration (FDA) recognizes the current and future value of pharmacogenetics in drug safety and development. A number of approved pharmacogenetic biomarkers are listed on the FDA website (Table 1). Black box warnings have been mandated for a number of drugs on the basis of observational evidence.

The FDA also promotes rapid approval for novel drugs with pharmacogenetic “companion diagnostics.” A recent example of this was the approval of ivacaftor for cystic fibrosis patients who have the G551D mutation.⁵ Here, a molecular understanding of the condition led to the development of a targeted treatment. Although the cost of developing this drug was high, the path is now paved for similar advances. Oncologists are familiar with these advances with the emergence of new molecularly targeted treatments, eg, BRAF inhibitors in metastatic melanoma, imatinib in chronic myeloid leukemia, and gefitinib in non-small-cell lung cancer.

PHARMACOGENETICS IN CARDIOVASCULAR MEDICINE

Cardiovascular medicine also stands to benefit from rapid advances in pharmacogenetics.

While no treatment has been developed that targets the molecular basis of cardiovascular disease, a number of genomic biomarkers have emerged that identify patients at risk of adverse reactions or treatment failure. These include genetic tests to predict the maintenance dose and risk of bleeding with warfarin,⁶ the likelihood of myopathy and myositis with simvastatin,⁷ and the risk of recurrent thrombotic events with clopidogrel.^8–10

Using pharmacogenetics in prescribing warfarin and its alternatives

The pharmacogenetics of warfarin has been extensively researched, but genotyping before prescribing this drug is not yet widely done.

In 2007, the FDA updated the labeling of warfarin to include information about the influence of two genes, VKORC1 and CYP2C9, on a patient’s response to this drug. In 2010 this was updated to add that testing for these genes could be used to predict the maintenance dose of the drug. Difficulties with algorithms used to integrate this into clinical practice have hindered adoption of this testing.

With the advent of new anticoagulants such as dabigatran, rivaroxaban, and apixaban, many have expected warfarin and its pharmacogenetics to become obsolete. However, the new agents cost considerably more. Further, they may not offer a very great advantage over warfarin: in the Randomized Evaluation of Long-term Anticoagulant Therapy (RE-LY) trial, the absolute risk reduction in intracranial hemorrhage with dabigatran vs warfarin was small.¹¹ Therefore, dabigatran is probably not cost-effective in populations at low risk of bleeding.¹² A cost-effectiveness analysis comparing warfarin with dabigatran in patients with uncomplicated atrial fibrillation has suggested that dabigatran is, however, cost-effective in patients at moderate risk.¹²

In the RE-LY trial, the international normalized ratios (INRs) of the patients in the warfarin group were in the therapeutic range only 64% of the time. The advantages of dabigatran over warfarin become less pronounced as warfarin control is tightened.¹³ Of note, pharmacogenetics and home monitoring of the INR have both been shown to lead to tighter control of the INR, with greater time within the therapeutic range.^14,15

Moreover, genetic testing can help us reduce the number of bleeding events in patients taking warfarin.¹⁶ Patients who carry the CYP2C9*2 or CYP2C9*3 polymorphism metabolize S-warfarin slower and therefore have a threefold higher risk of hemorrhage after starting warfarin.¹⁷ We could speculate that patients carrying these variants may be better served by the newer anticoagulants, though this has not been tested in any clinical trial.

It is also worth appreciating that the conditions requiring anticoagulation, such as atrial fibrillation, also have a strong genetic basis. Variants in chromosomes 4q25, 1q21, and 16q22 have all been associated with atrial fibrillation.¹⁸ The risk of atrial fibrillation is five to six times higher in carriers of multiple variants within all of these loci.¹⁹ Genetic variants at 4q25 have been associated with the response to specific antiarrhythmic drug treatments,²⁰ response to pulmonary vein isolation, ^21,22 and direct-current cardioversion.²³ One can imagine a future in which patients with palpitations, carrying multiple gene risk variants, will choose prolonged monitoring at home to confirm a diagnosis. They would then be provided with a personalized best management strategy, using their personal preferences, clinical data, and genetic profile to make a treatment decision.

Using pharmacogenetics in prescribing clopidogrel and its alternatives

The pharmacogenetics of clopidogrel is of particular interest, as it has the potential of establishing a rational basis for using newer antiplatelet drugs such as ticagrelor and prasugrel, which are considerably more expensive than generic clopidogrel.

Most of the people who do not respond to clopidogrel carry the common cytochrome P450 2C19 variants CYP2C19*2 or CYP2C19*3.⁹ These variants are present in particularly high frequency in Asians and African Americans, who often do not feature in large randomized trials.

Newer antiplatelet agents have failed to demonstrate consistent superiority to clopidogrel without a tradeoff of more bleeding. However, in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 39 (TRITON TIMI-38),^24,25 patients with the *2 variant receiving prasugrel had lower cardiovascular event rates than *2 carriers receiving clopidogrel.

Similarly, the patients who benefit the most from ticagrelor are carriers of the 2C19 nonresponder variants. In a large study, clopidogrel responders who did not carry either 2C19 nonresponder genetic variants or ABCB1 variants had cardiovascular outcomes similar to those of patients receiving ticagrelor.²⁶

Clinicians have been cautious in prescribing potent antiplatelet agents to all patients because of the risk of bleeding. One could assume that by reserving newer agents for clopidogrel nonresponders, the bleeding risk could be minimized and overall benefit could be preserved with this strategy.

Cost may also be contained. The cost-effectiveness of such an approach with prasugrel has been tested with computer modeling and appears favorable.²⁷ On the other hand, a similar yet limited analysis did not find genotype-driven use of ticagrelor to be cost-effective.²⁸ This was mostly due to fewer deaths in patients receiving ticagrelor. However, the cost estimate for genotype-guided therapy was overestimated, as heterozygotes in the model were treated with ticagrelor instead of a high dose of clopidogrel.

It now appears that heterozygotes, ie, patients with one copy of the nonresponder variant, can achieve similar platelet inhibition with clopidogrel 225 mg daily as noncarriers on 75 mg daily.²⁹ Since genotype-guided antiplatelet therapy has not been tested in a randomized outcomes trial, this tailored strategy has not been widely accepted.

THE FUTURE

The barriers to adoption of pharmacogenetics are considerable. Clinicians need to be educated about it, reimbursement needs to be worked out, and the pharmaceutical industry needs to get behind it. Nevertheless, the future of pharmacogenetics is extremely promising.

Research networks are forming to support the use of pharmacogenetics in clinical practice. The Pharmgkb (www.pharmgkb.org) database serves as a hub for educating clinicians and researchers as well as curating data for reference. Vanderbilt University is piloting the BioVu project, in which DNA and genotype data on patients are being stored and matched to the electronic clinical records.³⁰ These projects not only provide clinically useful information on the current state of the art of pharmacogenetics, they also aid in disseminating new information about genotype-phenotype relationships.

Analytical software that uses “natural language processing” is being applied to clinician-generated notes to derive new observations and associations between genetic variants and clinical phenotypes. Integrating this information in real-time decision-support modules in the electronic health record provides a feedback loop for a rapid assimilation of new knowledge. Similar innovative decision-support modules are being established by Cleveland Clinic’s Center for Personalized Healthcare.³¹

The rise of ‘omic’ sciences

Pharmacogenetics and pharmacogenomics are part of a larger set of “omic” sciences. The suffix “-omics” implies a larger, more holistic view and is being applied to a number of fields—for example, the study of proteins (proteomics) and the study of metabolites (metabolomics). Profiling proteins and metabolites delivers a deluge of information on a patient that can be clustered, using pattern-recognition software, into population subgroups. Patterns of multiple proteins or metabolites are extracted from this spectral data to identify disease or response to treatment (pharmacometabolomics).

Metabolomics has been shown to predict the response to statins,³² diagnose myocardial infarction,³³ and reclassify cardiovascular risk status.³⁴ In addition, whereas traditional laboratory chemistry is reductionist, using single biomarkers for single-disease diagnosis, omic technologies hold the potential to reveal information on a number of possible health or disease states. The identification of “healthy” profiles using these technologies can potentially provide positive feedback to patients undertaking lifestyle changes and treatment.

The instrument costs for proteomic and metabolomic profiling are relatively high. However, the ongoing running costs are minimal, estimated at as low as less than $13 per test, as there are no expensive reagents.³³ High-volume testing therefore becomes very cost-effective.

Although omic science appears futuristic, proteomics and metabolomics are already used in many clinical laboratories to rapidly identify bacteria. These methods have already revolutionized the way laboratories identify microbes, since they are automated, reduce workload, and give very fast results.

The cost of genetic testing is falling

Critics of pharmacogenetics claim that the predictive value of genetic testing is poor, that evidence is lacking, and that the cost is too high. In all new technologies, the first iteration is coarse, but performance improves with use. The first major barrier is adoption. Projects like BioVu are establishing the infrastructure for a feedback loop to iteratively improve upon the status quo and provide the evidence base clinicians demand.

The cost of genetic testing is falling rapidly, with whole-genome sequencing and annotation now costing less than $5,000. The cost of a pharmacogenetic test can be as low as $100 using low-cost nanotechnology, and the test needs to be performed only once in a patient’s lifetime.²⁷

As other related molecular technologies such as proteomics and metabolomics become available and are integrated with genomics, the predictive ability of this science will improve.

AWAY FROM ONE-SIZE-FITS-ALL MEDICINE

Over the last decade there has been a trend away from “one size fits all” to customized “markets of one” in everything from consumer products to education to medicine. Mass customizing, also known as personalization, has been embraced by the internet community as a means to increase efficiency and reduce cost. This occurs by eliminating waste in redundant work or production of ineffective products.

Personalization on the Internet has been enabled through the use of informatics, mathematics, and supercomputing. The same tools that have personalized the delivery of consumer products are also being applied to the field of pharmacogenetics. Applied in an evidence-based fashion, these new technologies should profoundly improve patient care now and in the future.

“Change is the only constant.”

—Heraclitus (c 535–475 bce)

With the cost of health care rising and money to pay for it shrinking, there has never been a greater need to reduce waste.

See related article

Ineffective treatments and adverse drug effects account for much preventable morbidity and expense. New treatments, touted as more potent, are often introduced as replacements for traditional ones that are still effective in many patients, adding to costs and the potential for harm. For the pharmaceutical industry, the search for new “blockbuster” drugs seems to have hit a wall, at least in cardiovascular medicine.¹ Advances often come at the cost of adverse effects, such as bleeding with triple antiplatelet therapy and diabetes with potent statin drugs.

The path to maximizing benefit and reducing harm now appears to lie in stratifying populations and appreciating patient individuality in response to treatment. For many decades we have known that patients vary widely in their response to drugs, owing to personal factors such as body surface area, age, environment, and genetics. And indeed, we treat our patients as individuals, for example by tailoring aminoglycoside dose to weight and renal function.

However, clinical trials typically give us an idea of the benefits only to the average patient. While subgroup analyses identify groups that may benefit more or less from treatment, the additional information they provide is not easily integrated into the clinical model of prescribing, in which one size fits all.

THE PROMISE OF PHARMACOGENETICS

The emerging field of pharmacogenetics promises to give clinicians the tools to make informed treatment decisions based on predictive genetic testing. This genetic testing aims to match treatment to an individual’s genetic profile. This often involves analyzing single-nucleotide polymorphisms in genes for enzymes that metabolize drugs, such as the cytochrome P450 enzymes, to predict efficacy or an adverse event with treatment.

Pharmacogenetics is playing an increasing role in clinical trials, particularly in the early stages of drug development, by helping to reduce the number of patients needed, prove efficacy, and identify subgroups in which alternative treatment can be targeted. At another level, a molecular understanding of disease is leading to truly targeted treatments based on genomics.

Over recent years, genetic testing has been increasingly used in clinical practice, thanks to a convergence of factors such as rapid, low-cost tests, a growing evidence base, and emerging interest among doctors and payers.

An advantage to using genetic testing as opposed to other types of laboratory testing, such as measuring the concentration of the drug in the blood during treatment, is that genetic tests can predict the response to treatment before the treatment is started. Moreover, with therapeutic drug monitoring after treatment has begun, there are sometimes no detectable measures of toxicity. For example, both carbamazepine and the antiviral drug abacavir can—fortunately only rarely—cause Stevens-Johnson syndrome. But before genetic markers were discovered, there was no method of estimating this risk apart from taking a family history.^2,3 Considering the numbers of people involved, it was not feasible until recently to suggest genetic screening for patients starting on these drugs. However, the cost of genotyping and gene sequencing has been falling at a rate inversely faster than Moore’s law (an approximate annual doubling in computer power), and population genomics is becoming a reality.⁴

The US Food and Drug Administration (FDA) recognizes the current and future value of pharmacogenetics in drug safety and development. A number of approved pharmacogenetic biomarkers are listed on the FDA website (Table 1). Black box warnings have been mandated for a number of drugs on the basis of observational evidence.

The FDA also promotes rapid approval for novel drugs with pharmacogenetic “companion diagnostics.” A recent example of this was the approval of ivacaftor for cystic fibrosis patients who have the G551D mutation.⁵ Here, a molecular understanding of the condition led to the development of a targeted treatment. Although the cost of developing this drug was high, the path is now paved for similar advances. Oncologists are familiar with these advances with the emergence of new molecularly targeted treatments, eg, BRAF inhibitors in metastatic melanoma, imatinib in chronic myeloid leukemia, and gefitinib in non-small-cell lung cancer.

PHARMACOGENETICS IN CARDIOVASCULAR MEDICINE

Cardiovascular medicine also stands to benefit from rapid advances in pharmacogenetics.

While no treatment has been developed that targets the molecular basis of cardiovascular disease, a number of genomic biomarkers have emerged that identify patients at risk of adverse reactions or treatment failure. These include genetic tests to predict the maintenance dose and risk of bleeding with warfarin,⁶ the likelihood of myopathy and myositis with simvastatin,⁷ and the risk of recurrent thrombotic events with clopidogrel.^8–10

Using pharmacogenetics in prescribing warfarin and its alternatives

The pharmacogenetics of warfarin has been extensively researched, but genotyping before prescribing this drug is not yet widely done.

In 2007, the FDA updated the labeling of warfarin to include information about the influence of two genes, VKORC1 and CYP2C9, on a patient’s response to this drug. In 2010 this was updated to add that testing for these genes could be used to predict the maintenance dose of the drug. Difficulties with algorithms used to integrate this into clinical practice have hindered adoption of this testing.

With the advent of new anticoagulants such as dabigatran, rivaroxaban, and apixaban, many have expected warfarin and its pharmacogenetics to become obsolete. However, the new agents cost considerably more. Further, they may not offer a very great advantage over warfarin: in the Randomized Evaluation of Long-term Anticoagulant Therapy (RE-LY) trial, the absolute risk reduction in intracranial hemorrhage with dabigatran vs warfarin was small.¹¹ Therefore, dabigatran is probably not cost-effective in populations at low risk of bleeding.¹² A cost-effectiveness analysis comparing warfarin with dabigatran in patients with uncomplicated atrial fibrillation has suggested that dabigatran is, however, cost-effective in patients at moderate risk.¹²

In the RE-LY trial, the international normalized ratios (INRs) of the patients in the warfarin group were in the therapeutic range only 64% of the time. The advantages of dabigatran over warfarin become less pronounced as warfarin control is tightened.¹³ Of note, pharmacogenetics and home monitoring of the INR have both been shown to lead to tighter control of the INR, with greater time within the therapeutic range.^14,15

Moreover, genetic testing can help us reduce the number of bleeding events in patients taking warfarin.¹⁶ Patients who carry the CYP2C9*2 or CYP2C9*3 polymorphism metabolize S-warfarin slower and therefore have a threefold higher risk of hemorrhage after starting warfarin.¹⁷ We could speculate that patients carrying these variants may be better served by the newer anticoagulants, though this has not been tested in any clinical trial.

It is also worth appreciating that the conditions requiring anticoagulation, such as atrial fibrillation, also have a strong genetic basis. Variants in chromosomes 4q25, 1q21, and 16q22 have all been associated with atrial fibrillation.¹⁸ The risk of atrial fibrillation is five to six times higher in carriers of multiple variants within all of these loci.¹⁹ Genetic variants at 4q25 have been associated with the response to specific antiarrhythmic drug treatments,²⁰ response to pulmonary vein isolation, ^21,22 and direct-current cardioversion.²³ One can imagine a future in which patients with palpitations, carrying multiple gene risk variants, will choose prolonged monitoring at home to confirm a diagnosis. They would then be provided with a personalized best management strategy, using their personal preferences, clinical data, and genetic profile to make a treatment decision.

Using pharmacogenetics in prescribing clopidogrel and its alternatives

The pharmacogenetics of clopidogrel is of particular interest, as it has the potential of establishing a rational basis for using newer antiplatelet drugs such as ticagrelor and prasugrel, which are considerably more expensive than generic clopidogrel.

Most of the people who do not respond to clopidogrel carry the common cytochrome P450 2C19 variants CYP2C19*2 or CYP2C19*3.⁹ These variants are present in particularly high frequency in Asians and African Americans, who often do not feature in large randomized trials.

Newer antiplatelet agents have failed to demonstrate consistent superiority to clopidogrel without a tradeoff of more bleeding. However, in the Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis in Myocardial Infarction 39 (TRITON TIMI-38),^24,25 patients with the *2 variant receiving prasugrel had lower cardiovascular event rates than *2 carriers receiving clopidogrel.

Similarly, the patients who benefit the most from ticagrelor are carriers of the 2C19 nonresponder variants. In a large study, clopidogrel responders who did not carry either 2C19 nonresponder genetic variants or ABCB1 variants had cardiovascular outcomes similar to those of patients receiving ticagrelor.²⁶

Clinicians have been cautious in prescribing potent antiplatelet agents to all patients because of the risk of bleeding. One could assume that by reserving newer agents for clopidogrel nonresponders, the bleeding risk could be minimized and overall benefit could be preserved with this strategy.

Cost may also be contained. The cost-effectiveness of such an approach with prasugrel has been tested with computer modeling and appears favorable.²⁷ On the other hand, a similar yet limited analysis did not find genotype-driven use of ticagrelor to be cost-effective.²⁸ This was mostly due to fewer deaths in patients receiving ticagrelor. However, the cost estimate for genotype-guided therapy was overestimated, as heterozygotes in the model were treated with ticagrelor instead of a high dose of clopidogrel.

It now appears that heterozygotes, ie, patients with one copy of the nonresponder variant, can achieve similar platelet inhibition with clopidogrel 225 mg daily as noncarriers on 75 mg daily.²⁹ Since genotype-guided antiplatelet therapy has not been tested in a randomized outcomes trial, this tailored strategy has not been widely accepted.

THE FUTURE

The barriers to adoption of pharmacogenetics are considerable. Clinicians need to be educated about it, reimbursement needs to be worked out, and the pharmaceutical industry needs to get behind it. Nevertheless, the future of pharmacogenetics is extremely promising.

Research networks are forming to support the use of pharmacogenetics in clinical practice. The Pharmgkb (www.pharmgkb.org) database serves as a hub for educating clinicians and researchers as well as curating data for reference. Vanderbilt University is piloting the BioVu project, in which DNA and genotype data on patients are being stored and matched to the electronic clinical records.³⁰ These projects not only provide clinically useful information on the current state of the art of pharmacogenetics, they also aid in disseminating new information about genotype-phenotype relationships.

Analytical software that uses “natural language processing” is being applied to clinician-generated notes to derive new observations and associations between genetic variants and clinical phenotypes. Integrating this information in real-time decision-support modules in the electronic health record provides a feedback loop for a rapid assimilation of new knowledge. Similar innovative decision-support modules are being established by Cleveland Clinic’s Center for Personalized Healthcare.³¹

The rise of ‘omic’ sciences

Pharmacogenetics and pharmacogenomics are part of a larger set of “omic” sciences. The suffix “-omics” implies a larger, more holistic view and is being applied to a number of fields—for example, the study of proteins (proteomics) and the study of metabolites (metabolomics). Profiling proteins and metabolites delivers a deluge of information on a patient that can be clustered, using pattern-recognition software, into population subgroups. Patterns of multiple proteins or metabolites are extracted from this spectral data to identify disease or response to treatment (pharmacometabolomics).

Metabolomics has been shown to predict the response to statins,³² diagnose myocardial infarction,³³ and reclassify cardiovascular risk status.³⁴ In addition, whereas traditional laboratory chemistry is reductionist, using single biomarkers for single-disease diagnosis, omic technologies hold the potential to reveal information on a number of possible health or disease states. The identification of “healthy” profiles using these technologies can potentially provide positive feedback to patients undertaking lifestyle changes and treatment.

The instrument costs for proteomic and metabolomic profiling are relatively high. However, the ongoing running costs are minimal, estimated at as low as less than $13 per test, as there are no expensive reagents.³³ High-volume testing therefore becomes very cost-effective.

Although omic science appears futuristic, proteomics and metabolomics are already used in many clinical laboratories to rapidly identify bacteria. These methods have already revolutionized the way laboratories identify microbes, since they are automated, reduce workload, and give very fast results.

The cost of genetic testing is falling

Critics of pharmacogenetics claim that the predictive value of genetic testing is poor, that evidence is lacking, and that the cost is too high. In all new technologies, the first iteration is coarse, but performance improves with use. The first major barrier is adoption. Projects like BioVu are establishing the infrastructure for a feedback loop to iteratively improve upon the status quo and provide the evidence base clinicians demand.

The cost of genetic testing is falling rapidly, with whole-genome sequencing and annotation now costing less than $5,000. The cost of a pharmacogenetic test can be as low as $100 using low-cost nanotechnology, and the test needs to be performed only once in a patient’s lifetime.²⁷

As other related molecular technologies such as proteomics and metabolomics become available and are integrated with genomics, the predictive ability of this science will improve.

AWAY FROM ONE-SIZE-FITS-ALL MEDICINE

Over the last decade there has been a trend away from “one size fits all” to customized “markets of one” in everything from consumer products to education to medicine. Mass customizing, also known as personalization, has been embraced by the internet community as a means to increase efficiency and reduce cost. This occurs by eliminating waste in redundant work or production of ineffective products.

Personalization on the Internet has been enabled through the use of informatics, mathematics, and supercomputing. The same tools that have personalized the delivery of consumer products are also being applied to the field of pharmacogenetics. Applied in an evidence-based fashion, these new technologies should profoundly improve patient care now and in the future.

The answer is not clear. There is evidence in favor of pharmacogenetic testing, but not yet enough to strongly recommend it. However, we do believe that physicians should consider it when starting patients on warfarin therapy.

See related commentary

WARFARIN HAS A NARROW THERAPEUTIC WINDOW

Although newer drugs are available, warfarin is still the most commonly used oral anticoagulant for preventing and treating thromboembolism.¹ It is highly effective but has a narrow therapeutic window and wide interindividual variability in dosage requirements, which poses challenges to achieving adequate anticoagulation.^1–3 Inappropriate dosing contributes to a high rate of bleeding events and emergency room visits.⁴

Warfarin is monitored using the prothrombin time. Because the prothrombin time varies depending on the assay used, the standardized value called the international normalized ratio (INR) is more commonly used.

Clinical factors such as age, body size, and drug interactions affect warfarin dosage requirements and are important to consider,⁵ even though they account for only 15% to 20% of the variability in warfarin dose.⁶

Genetic factors also affect warfarin dosage requirements. The combination of genetic and clinical factors accounts for up to 47% of the dose variability.⁷

GENES THAT AFFECT WARFARIN

Several genes are known to influence warfarin’s pharmacokinetics and pharmacodynamics. Of these, the two most clinically relevant and well studied are CYP2C9 (which codes for cytochrome P450 2C9) and VKORC1 (which codes for vitamin K epoxide reductase).⁷ These genes are polymorphic, with some variants producing less-active enzymes that allow warfarin to be more active. Therefore, patients who carry these variants need lower doses of this drug (see below).

CYP2C9 variants

The CYP2C9 gene has several variants. Of these, CYP2C9*2 and CYP2C9*3 are associated with the lowest enzyme activity.

Patients with either of these variants require significantly lower warfarin doses to reach therapeutic levels than those with the wild-type gene (ie, CYP2C9*1). CYP2C9*2 reduces warfarin clearance by 40%, and the CYP2C9*3 variant reduces it by 75%.⁷ Having a *2 or *3 allele increases the risk of bleeding during warfarin therapy and the time needed to achieve a stable dose.⁸ Other variants associated with lower warfarin dose requirements are *5, *6, and *11.

The prevalence of these variants is significantly higher in people of European ancestry (roughly one-third) than in Asian people and African Americans,⁷ although no one has recommended not testing in these low-prevalence populations. Limdi et al⁹ reported that by including the *5, *6, and *11 variants in genetic testing (in addition to *2 and *3), they could identify more African Americans (9.7%) who carried at least one of these abnormal variants than reported previously. Differences among ethnic groups need to be taken into account when interpreting pharmacogenetic studies.

VKORC1 variants

Patients also need lower doses of warfarin if they carry the VKORC1 −1639G>A variant, and they spend more time with an INR above the therapeutic range and have higher overall INR values. However, having this variant does not appear to increase the risk of bleeding.

The −1639G>A variant is the most common variant of VKORC1. Rarer ones have also been described, but most commercially available tests do not detect them.

Racial differences exist in the prevalence rates of the various VKORC1 polymorphisms, with the most sensitive (low-dose) genotype predominating in Asians and the least sensitive (high-dose) genotype predominating in African Americans. Over 50% of people of European ancestry carry the intermediate-sensitivity genotype (typical dose).⁷

CURRENT RECOMMENDATIONS FOR OR AGAINST TESTING

FDA labeling

In 2007, the US Food and Drug Administration (FDA) required that the warfarin package insert carry information about initial dosing based on CYP2C9 and VKORC1 testing. This recommendation was revised in 2010 to include a table to help clinicians select an initial warfarin dose if CYP2C9 and VKORC1 genotype information is available. However, the FDA does not require pharmacogenetic testing, leaving the decision to the discretion of the clinician.⁷

American College of Chest Physicians

The American College of Chest Physicians recommends against routine pharmacogenetic testing (grade 1B) because of a lack of evidence that it improves clinical end points or that it is cost-effective.⁵

WHAT EVIDENCE SUPORTS GENETIC TESTING TO GUIDE WARFARIN THERAPY?

To date, no large randomized, controlled trial has been published that looked at clinical outcomes with warfarin dosing based on pharmacogenetic testing. However, several smaller studies have suggested it is beneficial.

One trial found that when dosing was informed by pharmacogenetic testing, patients had significantly more time in the therapeutic range, a lower percentage of INRs greater than 4 or less than 1.5, and fewer serious adverse events (death, myocardial infarction, stroke, thromboembolism, and clinically significant bleeding events).¹⁰ Patients whose dosage was determined using pharmacogenetic algorithms as opposed to traditional clinical algorithms maintained a therapeutic INR more consistently.¹¹

In addition, compared with historical controls, patients whose physician used pharmacogenetic testing to guide warfarin dosing had a rate of hospitalization 31% lower and a rate of hospitalization specifically for bleeding or thromboembolism 28% lower during 6 months of follow-up.^12,13

Several studies have attempted to assess the cost-effectiveness and utility of pharmacogenetic testing in warfarin therapy. As yet, the results have been inconclusive.¹⁴ Larger prospective trials are under way and are estimated to be completed in late 2013.¹⁵ These include:

• COAG (Clarification of Optimal Anticoagulation Through Genetics)
• GIFT (Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis)
• EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin).

We hope these studies will provide greater clarity on the clinical utility and cost-effectiveness of pharmacogenetic testing to guide warfarin dosing.

HOW SHOULD GENETIC INFORMATION BE USED TO GUIDE OR ALTER THERAPY?

Algorithms are available for estimating initial and maintenance warfarin doses based on genetic information (CYP2C9 and VKORC1), race or ethnicity, age, sex, body mass index, smoking status, and other medications taken. In addition, models incorporating the INR on day 4 and days 6 to 11 have been developed for dose refinement.¹⁵ The algorithms explain 30% to 60% of the variability of the data, with lower values for African Americans.⁷

A well-developed dosing model that includes traditional clinical factors and patient genetic status is publicly available online at www.warfarindosing.org.⁴

CPIC: A leader in applied pharmacogenetics

In late 2009, PharmGKB joined forces with the Pharmacogenomics Research Network of the National Institutes of Health to form the Clinical Pharmacogenetics Implementation Consortium (CPIC). This organization issues guidelines that are written by expert clinicians and scientists and then are peer-reviewed, published in leading journals, and simultaneously posted to the PharmGKB website along with supplemental information and updates.

CPIC’s goal is to review the current evidence and to address barriers to the adoption of pharmacogenetic testing into clinical practice. Its guidelines do not advise when or which pharmacogenetic tests should be ordered. Rather, they provide guidance on interpreting and applying such testing, should the test results be available.⁷

CPIC has guidelines on CYP2C9 and VKORC1 genotypes and warfarin dosing.⁸ If a patient’s genetic information is available, CPIC strongly recommends the use of pharmacogenetic algorithm-based dosing. If such an algorithm is not accessible, use of a genotype dosing table is recommended.⁸

Monitoring is still needed

Many factors can affect an individual’s response to warfarin above and beyond the above-noted clinical and genetic traits. These include diet, concomitant medications (both prescription and over-the-counter and herbal), and disease state. There may also be additional genetic polymorphisms not yet identified in various racial and ethnic groups that may affect dosing requirements. And as with all medications, patient compliance and dosing errors have a large potential to affect individual response. Therefore, clinicians should still be diligent about clinical monitoring.¹⁵

Most useful for initial dose

As with most pharmacogenetic information, the greatest benefit can be achieved when this information is used to guide the initial dose, although there is also some effect noted when this information is known and acted upon into the 2nd week of treatment.⁸

Patients on long-term warfarin treatment with stable doses and those unable to achieve stable dosing because of variable adherence or dietary vitamin K intake are less likely to benefit from genetic testing.

There are no published guidelines on the utility of pharmacogenetic testing if a patient is already on a stable dose of warfarin or has a known historical stable dose. There are also no published guidelines on changing the frequency of monitoring based on known genotype.

In children, the data are sparse at this time regarding the utility of pharmacogenetically informed dosing.

HOW DOES ONE ORDER TESTING, AND WHAT IS THE COST?

The FDA has approved four warfarin pharmacogenetic test kits. To be used in clinical decision-making, these tests must be done in a laboratory certified by the Clinical Laboratory Improvement Amendments (CLIA) program.

Testing typically costs a few hundred dollars and may take days for results to be returned if not available on site.¹⁵ At Cleveland Clinic, CYP2C9 and VKORC1 testing can be run in-house at a cost of about $700. Generally, many third-party payers do not reimburse for testing without a prior-approval process.

TO TEST OR NOT TO TEST

Pharmacogenetic testing is available and may help optimize warfarin dosing early in treatment, as well as help maintain therapeutic INRs more consistently. There is preliminary evidence that using this information to guide dosing improves clinical outcomes. Several large trials are under way to address additional questions of clinical utility, with results expected in the next year. There are also readily available decision-support tools to guide therapeutic dosing, and when pharmacogenetic test results are available, utilization of a warfarin dosing algorithm is recommended.

The largest barrier remaining appears to be cost (relative to perceived benefit), and until larger trials of clinical utility and cost-effectiveness are completed and analyzed, hurdles exist to obtaining coverage for such testing.

If it is readily available (and can be paid for by insurance companies or out-of-pocket) and test results can be obtained within 24 to 48 hours or before prescribing, pharmacogenetic testing can be a valuable tool to guide and manage warfarin dosing. Particularly for patients who want to be as proactive as possible, warfarin pharmacogenetic testing offers the ability to participate in this decision-making and to potentially reduce their risk of adverse drug events. And in view of the evidence and FDA recommendations, we propose that the discussion with our patients is not whether we should consider pharmacogenetic testing, but that we have considered pharmacogenetic testing, and why we have decided for or against it.

The answer is not clear. There is evidence in favor of pharmacogenetic testing, but not yet enough to strongly recommend it. However, we do believe that physicians should consider it when starting patients on warfarin therapy.

See related commentary

WARFARIN HAS A NARROW THERAPEUTIC WINDOW

Although newer drugs are available, warfarin is still the most commonly used oral anticoagulant for preventing and treating thromboembolism.¹ It is highly effective but has a narrow therapeutic window and wide interindividual variability in dosage requirements, which poses challenges to achieving adequate anticoagulation.^1–3 Inappropriate dosing contributes to a high rate of bleeding events and emergency room visits.⁴

Warfarin is monitored using the prothrombin time. Because the prothrombin time varies depending on the assay used, the standardized value called the international normalized ratio (INR) is more commonly used.

Clinical factors such as age, body size, and drug interactions affect warfarin dosage requirements and are important to consider,⁵ even though they account for only 15% to 20% of the variability in warfarin dose.⁶

Genetic factors also affect warfarin dosage requirements. The combination of genetic and clinical factors accounts for up to 47% of the dose variability.⁷

GENES THAT AFFECT WARFARIN

Several genes are known to influence warfarin’s pharmacokinetics and pharmacodynamics. Of these, the two most clinically relevant and well studied are CYP2C9 (which codes for cytochrome P450 2C9) and VKORC1 (which codes for vitamin K epoxide reductase).⁷ These genes are polymorphic, with some variants producing less-active enzymes that allow warfarin to be more active. Therefore, patients who carry these variants need lower doses of this drug (see below).

CYP2C9 variants

The CYP2C9 gene has several variants. Of these, CYP2C9*2 and CYP2C9*3 are associated with the lowest enzyme activity.

Patients with either of these variants require significantly lower warfarin doses to reach therapeutic levels than those with the wild-type gene (ie, CYP2C9*1). CYP2C9*2 reduces warfarin clearance by 40%, and the CYP2C9*3 variant reduces it by 75%.⁷ Having a *2 or *3 allele increases the risk of bleeding during warfarin therapy and the time needed to achieve a stable dose.⁸ Other variants associated with lower warfarin dose requirements are *5, *6, and *11.

The prevalence of these variants is significantly higher in people of European ancestry (roughly one-third) than in Asian people and African Americans,⁷ although no one has recommended not testing in these low-prevalence populations. Limdi et al⁹ reported that by including the *5, *6, and *11 variants in genetic testing (in addition to *2 and *3), they could identify more African Americans (9.7%) who carried at least one of these abnormal variants than reported previously. Differences among ethnic groups need to be taken into account when interpreting pharmacogenetic studies.

VKORC1 variants

Patients also need lower doses of warfarin if they carry the VKORC1 −1639G>A variant, and they spend more time with an INR above the therapeutic range and have higher overall INR values. However, having this variant does not appear to increase the risk of bleeding.

The −1639G>A variant is the most common variant of VKORC1. Rarer ones have also been described, but most commercially available tests do not detect them.

Racial differences exist in the prevalence rates of the various VKORC1 polymorphisms, with the most sensitive (low-dose) genotype predominating in Asians and the least sensitive (high-dose) genotype predominating in African Americans. Over 50% of people of European ancestry carry the intermediate-sensitivity genotype (typical dose).⁷

CURRENT RECOMMENDATIONS FOR OR AGAINST TESTING

FDA labeling

In 2007, the US Food and Drug Administration (FDA) required that the warfarin package insert carry information about initial dosing based on CYP2C9 and VKORC1 testing. This recommendation was revised in 2010 to include a table to help clinicians select an initial warfarin dose if CYP2C9 and VKORC1 genotype information is available. However, the FDA does not require pharmacogenetic testing, leaving the decision to the discretion of the clinician.⁷

American College of Chest Physicians

The American College of Chest Physicians recommends against routine pharmacogenetic testing (grade 1B) because of a lack of evidence that it improves clinical end points or that it is cost-effective.⁵

WHAT EVIDENCE SUPORTS GENETIC TESTING TO GUIDE WARFARIN THERAPY?

To date, no large randomized, controlled trial has been published that looked at clinical outcomes with warfarin dosing based on pharmacogenetic testing. However, several smaller studies have suggested it is beneficial.

One trial found that when dosing was informed by pharmacogenetic testing, patients had significantly more time in the therapeutic range, a lower percentage of INRs greater than 4 or less than 1.5, and fewer serious adverse events (death, myocardial infarction, stroke, thromboembolism, and clinically significant bleeding events).¹⁰ Patients whose dosage was determined using pharmacogenetic algorithms as opposed to traditional clinical algorithms maintained a therapeutic INR more consistently.¹¹

In addition, compared with historical controls, patients whose physician used pharmacogenetic testing to guide warfarin dosing had a rate of hospitalization 31% lower and a rate of hospitalization specifically for bleeding or thromboembolism 28% lower during 6 months of follow-up.^12,13

Several studies have attempted to assess the cost-effectiveness and utility of pharmacogenetic testing in warfarin therapy. As yet, the results have been inconclusive.¹⁴ Larger prospective trials are under way and are estimated to be completed in late 2013.¹⁵ These include:

• COAG (Clarification of Optimal Anticoagulation Through Genetics)
• GIFT (Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis)
• EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin).

We hope these studies will provide greater clarity on the clinical utility and cost-effectiveness of pharmacogenetic testing to guide warfarin dosing.

HOW SHOULD GENETIC INFORMATION BE USED TO GUIDE OR ALTER THERAPY?

Algorithms are available for estimating initial and maintenance warfarin doses based on genetic information (CYP2C9 and VKORC1), race or ethnicity, age, sex, body mass index, smoking status, and other medications taken. In addition, models incorporating the INR on day 4 and days 6 to 11 have been developed for dose refinement.¹⁵ The algorithms explain 30% to 60% of the variability of the data, with lower values for African Americans.⁷

A well-developed dosing model that includes traditional clinical factors and patient genetic status is publicly available online at www.warfarindosing.org.⁴

CPIC: A leader in applied pharmacogenetics

In late 2009, PharmGKB joined forces with the Pharmacogenomics Research Network of the National Institutes of Health to form the Clinical Pharmacogenetics Implementation Consortium (CPIC). This organization issues guidelines that are written by expert clinicians and scientists and then are peer-reviewed, published in leading journals, and simultaneously posted to the PharmGKB website along with supplemental information and updates.

CPIC’s goal is to review the current evidence and to address barriers to the adoption of pharmacogenetic testing into clinical practice. Its guidelines do not advise when or which pharmacogenetic tests should be ordered. Rather, they provide guidance on interpreting and applying such testing, should the test results be available.⁷

CPIC has guidelines on CYP2C9 and VKORC1 genotypes and warfarin dosing.⁸ If a patient’s genetic information is available, CPIC strongly recommends the use of pharmacogenetic algorithm-based dosing. If such an algorithm is not accessible, use of a genotype dosing table is recommended.⁸

Monitoring is still needed

Many factors can affect an individual’s response to warfarin above and beyond the above-noted clinical and genetic traits. These include diet, concomitant medications (both prescription and over-the-counter and herbal), and disease state. There may also be additional genetic polymorphisms not yet identified in various racial and ethnic groups that may affect dosing requirements. And as with all medications, patient compliance and dosing errors have a large potential to affect individual response. Therefore, clinicians should still be diligent about clinical monitoring.¹⁵

Most useful for initial dose

As with most pharmacogenetic information, the greatest benefit can be achieved when this information is used to guide the initial dose, although there is also some effect noted when this information is known and acted upon into the 2nd week of treatment.⁸

Patients on long-term warfarin treatment with stable doses and those unable to achieve stable dosing because of variable adherence or dietary vitamin K intake are less likely to benefit from genetic testing.

There are no published guidelines on the utility of pharmacogenetic testing if a patient is already on a stable dose of warfarin or has a known historical stable dose. There are also no published guidelines on changing the frequency of monitoring based on known genotype.

In children, the data are sparse at this time regarding the utility of pharmacogenetically informed dosing.

HOW DOES ONE ORDER TESTING, AND WHAT IS THE COST?

The FDA has approved four warfarin pharmacogenetic test kits. To be used in clinical decision-making, these tests must be done in a laboratory certified by the Clinical Laboratory Improvement Amendments (CLIA) program.

Testing typically costs a few hundred dollars and may take days for results to be returned if not available on site.¹⁵ At Cleveland Clinic, CYP2C9 and VKORC1 testing can be run in-house at a cost of about $700. Generally, many third-party payers do not reimburse for testing without a prior-approval process.

TO TEST OR NOT TO TEST

Pharmacogenetic testing is available and may help optimize warfarin dosing early in treatment, as well as help maintain therapeutic INRs more consistently. There is preliminary evidence that using this information to guide dosing improves clinical outcomes. Several large trials are under way to address additional questions of clinical utility, with results expected in the next year. There are also readily available decision-support tools to guide therapeutic dosing, and when pharmacogenetic test results are available, utilization of a warfarin dosing algorithm is recommended.

The largest barrier remaining appears to be cost (relative to perceived benefit), and until larger trials of clinical utility and cost-effectiveness are completed and analyzed, hurdles exist to obtaining coverage for such testing.

If it is readily available (and can be paid for by insurance companies or out-of-pocket) and test results can be obtained within 24 to 48 hours or before prescribing, pharmacogenetic testing can be a valuable tool to guide and manage warfarin dosing. Particularly for patients who want to be as proactive as possible, warfarin pharmacogenetic testing offers the ability to participate in this decision-making and to potentially reduce their risk of adverse drug events. And in view of the evidence and FDA recommendations, we propose that the discussion with our patients is not whether we should consider pharmacogenetic testing, but that we have considered pharmacogenetic testing, and why we have decided for or against it.

The answer is not clear. There is evidence in favor of pharmacogenetic testing, but not yet enough to strongly recommend it. However, we do believe that physicians should consider it when starting patients on warfarin therapy.

See related commentary

WARFARIN HAS A NARROW THERAPEUTIC WINDOW

Although newer drugs are available, warfarin is still the most commonly used oral anticoagulant for preventing and treating thromboembolism.¹ It is highly effective but has a narrow therapeutic window and wide interindividual variability in dosage requirements, which poses challenges to achieving adequate anticoagulation.^1–3 Inappropriate dosing contributes to a high rate of bleeding events and emergency room visits.⁴

Warfarin is monitored using the prothrombin time. Because the prothrombin time varies depending on the assay used, the standardized value called the international normalized ratio (INR) is more commonly used.

Clinical factors such as age, body size, and drug interactions affect warfarin dosage requirements and are important to consider,⁵ even though they account for only 15% to 20% of the variability in warfarin dose.⁶

Genetic factors also affect warfarin dosage requirements. The combination of genetic and clinical factors accounts for up to 47% of the dose variability.⁷

GENES THAT AFFECT WARFARIN

Several genes are known to influence warfarin’s pharmacokinetics and pharmacodynamics. Of these, the two most clinically relevant and well studied are CYP2C9 (which codes for cytochrome P450 2C9) and VKORC1 (which codes for vitamin K epoxide reductase).⁷ These genes are polymorphic, with some variants producing less-active enzymes that allow warfarin to be more active. Therefore, patients who carry these variants need lower doses of this drug (see below).

CYP2C9 variants

The CYP2C9 gene has several variants. Of these, CYP2C9*2 and CYP2C9*3 are associated with the lowest enzyme activity.

Patients with either of these variants require significantly lower warfarin doses to reach therapeutic levels than those with the wild-type gene (ie, CYP2C9*1). CYP2C9*2 reduces warfarin clearance by 40%, and the CYP2C9*3 variant reduces it by 75%.⁷ Having a *2 or *3 allele increases the risk of bleeding during warfarin therapy and the time needed to achieve a stable dose.⁸ Other variants associated with lower warfarin dose requirements are *5, *6, and *11.

The prevalence of these variants is significantly higher in people of European ancestry (roughly one-third) than in Asian people and African Americans,⁷ although no one has recommended not testing in these low-prevalence populations. Limdi et al⁹ reported that by including the *5, *6, and *11 variants in genetic testing (in addition to *2 and *3), they could identify more African Americans (9.7%) who carried at least one of these abnormal variants than reported previously. Differences among ethnic groups need to be taken into account when interpreting pharmacogenetic studies.

VKORC1 variants

Patients also need lower doses of warfarin if they carry the VKORC1 −1639G>A variant, and they spend more time with an INR above the therapeutic range and have higher overall INR values. However, having this variant does not appear to increase the risk of bleeding.

The −1639G>A variant is the most common variant of VKORC1. Rarer ones have also been described, but most commercially available tests do not detect them.

Racial differences exist in the prevalence rates of the various VKORC1 polymorphisms, with the most sensitive (low-dose) genotype predominating in Asians and the least sensitive (high-dose) genotype predominating in African Americans. Over 50% of people of European ancestry carry the intermediate-sensitivity genotype (typical dose).⁷

CURRENT RECOMMENDATIONS FOR OR AGAINST TESTING

FDA labeling

In 2007, the US Food and Drug Administration (FDA) required that the warfarin package insert carry information about initial dosing based on CYP2C9 and VKORC1 testing. This recommendation was revised in 2010 to include a table to help clinicians select an initial warfarin dose if CYP2C9 and VKORC1 genotype information is available. However, the FDA does not require pharmacogenetic testing, leaving the decision to the discretion of the clinician.⁷

American College of Chest Physicians

The American College of Chest Physicians recommends against routine pharmacogenetic testing (grade 1B) because of a lack of evidence that it improves clinical end points or that it is cost-effective.⁵

WHAT EVIDENCE SUPORTS GENETIC TESTING TO GUIDE WARFARIN THERAPY?

To date, no large randomized, controlled trial has been published that looked at clinical outcomes with warfarin dosing based on pharmacogenetic testing. However, several smaller studies have suggested it is beneficial.

One trial found that when dosing was informed by pharmacogenetic testing, patients had significantly more time in the therapeutic range, a lower percentage of INRs greater than 4 or less than 1.5, and fewer serious adverse events (death, myocardial infarction, stroke, thromboembolism, and clinically significant bleeding events).¹⁰ Patients whose dosage was determined using pharmacogenetic algorithms as opposed to traditional clinical algorithms maintained a therapeutic INR more consistently.¹¹

In addition, compared with historical controls, patients whose physician used pharmacogenetic testing to guide warfarin dosing had a rate of hospitalization 31% lower and a rate of hospitalization specifically for bleeding or thromboembolism 28% lower during 6 months of follow-up.^12,13

Several studies have attempted to assess the cost-effectiveness and utility of pharmacogenetic testing in warfarin therapy. As yet, the results have been inconclusive.¹⁴ Larger prospective trials are under way and are estimated to be completed in late 2013.¹⁵ These include:

• COAG (Clarification of Optimal Anticoagulation Through Genetics)
• GIFT (Genetics Informatics Trial of Warfarin to Prevent Venous Thrombosis)
• EU-PACT (European Pharmacogenetics of Anticoagulant Therapy-Warfarin).

We hope these studies will provide greater clarity on the clinical utility and cost-effectiveness of pharmacogenetic testing to guide warfarin dosing.

HOW SHOULD GENETIC INFORMATION BE USED TO GUIDE OR ALTER THERAPY?

Algorithms are available for estimating initial and maintenance warfarin doses based on genetic information (CYP2C9 and VKORC1), race or ethnicity, age, sex, body mass index, smoking status, and other medications taken. In addition, models incorporating the INR on day 4 and days 6 to 11 have been developed for dose refinement.¹⁵ The algorithms explain 30% to 60% of the variability of the data, with lower values for African Americans.⁷

A well-developed dosing model that includes traditional clinical factors and patient genetic status is publicly available online at www.warfarindosing.org.⁴

CPIC: A leader in applied pharmacogenetics

In late 2009, PharmGKB joined forces with the Pharmacogenomics Research Network of the National Institutes of Health to form the Clinical Pharmacogenetics Implementation Consortium (CPIC). This organization issues guidelines that are written by expert clinicians and scientists and then are peer-reviewed, published in leading journals, and simultaneously posted to the PharmGKB website along with supplemental information and updates.

CPIC’s goal is to review the current evidence and to address barriers to the adoption of pharmacogenetic testing into clinical practice. Its guidelines do not advise when or which pharmacogenetic tests should be ordered. Rather, they provide guidance on interpreting and applying such testing, should the test results be available.⁷

CPIC has guidelines on CYP2C9 and VKORC1 genotypes and warfarin dosing.⁸ If a patient’s genetic information is available, CPIC strongly recommends the use of pharmacogenetic algorithm-based dosing. If such an algorithm is not accessible, use of a genotype dosing table is recommended.⁸

Monitoring is still needed

Many factors can affect an individual’s response to warfarin above and beyond the above-noted clinical and genetic traits. These include diet, concomitant medications (both prescription and over-the-counter and herbal), and disease state. There may also be additional genetic polymorphisms not yet identified in various racial and ethnic groups that may affect dosing requirements. And as with all medications, patient compliance and dosing errors have a large potential to affect individual response. Therefore, clinicians should still be diligent about clinical monitoring.¹⁵

Most useful for initial dose

As with most pharmacogenetic information, the greatest benefit can be achieved when this information is used to guide the initial dose, although there is also some effect noted when this information is known and acted upon into the 2nd week of treatment.⁸

Patients on long-term warfarin treatment with stable doses and those unable to achieve stable dosing because of variable adherence or dietary vitamin K intake are less likely to benefit from genetic testing.

There are no published guidelines on the utility of pharmacogenetic testing if a patient is already on a stable dose of warfarin or has a known historical stable dose. There are also no published guidelines on changing the frequency of monitoring based on known genotype.

In children, the data are sparse at this time regarding the utility of pharmacogenetically informed dosing.

HOW DOES ONE ORDER TESTING, AND WHAT IS THE COST?

The FDA has approved four warfarin pharmacogenetic test kits. To be used in clinical decision-making, these tests must be done in a laboratory certified by the Clinical Laboratory Improvement Amendments (CLIA) program.

Testing typically costs a few hundred dollars and may take days for results to be returned if not available on site.¹⁵ At Cleveland Clinic, CYP2C9 and VKORC1 testing can be run in-house at a cost of about $700. Generally, many third-party payers do not reimburse for testing without a prior-approval process.

TO TEST OR NOT TO TEST

Pharmacogenetic testing is available and may help optimize warfarin dosing early in treatment, as well as help maintain therapeutic INRs more consistently. There is preliminary evidence that using this information to guide dosing improves clinical outcomes. Several large trials are under way to address additional questions of clinical utility, with results expected in the next year. There are also readily available decision-support tools to guide therapeutic dosing, and when pharmacogenetic test results are available, utilization of a warfarin dosing algorithm is recommended.

The largest barrier remaining appears to be cost (relative to perceived benefit), and until larger trials of clinical utility and cost-effectiveness are completed and analyzed, hurdles exist to obtaining coverage for such testing.

If it is readily available (and can be paid for by insurance companies or out-of-pocket) and test results can be obtained within 24 to 48 hours or before prescribing, pharmacogenetic testing can be a valuable tool to guide and manage warfarin dosing. Particularly for patients who want to be as proactive as possible, warfarin pharmacogenetic testing offers the ability to participate in this decision-making and to potentially reduce their risk of adverse drug events. And in view of the evidence and FDA recommendations, we propose that the discussion with our patients is not whether we should consider pharmacogenetic testing, but that we have considered pharmacogenetic testing, and why we have decided for or against it.

At the dawn of the genomics era, is the family history still relevant? The answer is a resounding yes.^1,2

The family history is clinically useful because it is a proxy for genetic, environmental, and behavioral risks to health. It can be used to inform risk stratification, allowing for judicious use of screening and opening the door to early and even prophylactic treatment.^3–8 As people live longer, we will need to detect common chronic conditions early in their course so that we can continue to improve health outcomes. Family history can help physicians personalize preventive care for conditions such as diabetes, osteoporosis, and cancers of the breast, colon, and prostate.^2,9–15

However, there is ample evidence that the family history is underused. Most practitioners ask about it infrequently and inconsistently.^16,17 Why is this, and how can we encourage the use of this powerful tool to enhance our daily clinical practice and improve care?

We will discuss here some of the challenges that make it difficult for physicians to collect and use the family history in clinical practice, and review strategies for collecting and using the family history in a more consistent manner. We anticipate that this discussion will be helpful to clinicians, as the family history is an essential input to personalized, preventive care plans.

CHALLENGE 1: ARE PATIENTS’ REPORTS RELIABLE?

A question that often arises when discussing the utility of the family history is the reliability of patients’ reports. Can we trust that patients can accurately report their family history? For many conditions, the answer is yes.^18,19

Ziogas and Anton-Culverl²⁰ asked 1,111 cancer patients whether their relatives had ever had cancer and verified their answers. In more than 95% of cases, if the patient said that a first-degree or second-degree relative did not have cancer of any type, that relative truly did not have cancer. Overall, over-reporting of cancer was rare, occurring in 2.4% of cases.

If the patient said that a relative did have cancer, that statement was usually true as well. The reliability of a report of cancer in first-degree relatives was greater than 75% for most types of cancer (female breast, ovarian, esophageal, colorectal, pancreas, lung, melanoma, brain, thyroid, lymphoma, leukemia). For several of these types of cancer (female breast, colorectal, and brain), the reliability was 90% or higher. For second-degree relatives, the reliability of a reported positive history was moderate (50% to 80%) for the same types of cancer, and for third-degree relatives, the reliability dropped further for all types of cancer except female breast, brain, pancreas, and leukemia, for which the reliability of a positive report remained at 70%.

Wideroff et al²¹ had similar findings in a study of more than 1,000 patients and more than 20,000 of their relatives.

Yoon et al,¹⁸ at the US Centers for Disease Control and Prevention, developed a Web-based risk-assessment tool called Family Healthware, currently undergoing validation trials. They found that patients’ reports were highly reliable for coronary heart disease, stroke, diabetes, and breast, ovarian, and colorectal cancers. They also calculated the degree of risk associated with a positive family history and the prevalence of a family history of each of these diseases.

For the primary care physician, these studies support the reliability of patients’ reports and provide guidance for targeting specific conditions when obtaining a family history.

CHALLENGE 2: NO TIME OR REIMBURSEMENT

Perhaps the most obvious barriers to collecting a family history are lack of time and reimbursement.

Acheson et al,¹⁷ in an observational study of 138 primary care physicians and 4,454 patient visits, found that family history was discussed during 51% of new patient visits and 22% of established patient visits. The rate at which the family history was taken varied from 0% (some physicians never asked) to 81% of all patient visits. On average, physicians spent less than 2.5 minutes collecting the family history.

Not surprisingly, the family history was discussed more often at well-care visits than at illness visits, as the former type of visit tends to be longer and, by definition, to be spent partly on preventive care. A difficulty with this strategy is that, given the shortage of primary care physicians, limited access, and patient preference, most preventive-care visits are combined with problem-focused visits, further decreasing the time available to collect and discuss a family history. While some argue that the family history should routinely be obtained and discussed during preventive-care visits regardless of reimbursement and time, the reality is that it may simply drop on the list of priorities for each visit.

Rich et al³ estimated that taking a family history would increase reimbursement for only one new patient evaluation and management code (99202) and one return-visit code (99213) in Current Procedural Terminology. This action would increase reimbursement enough to support about 10 minutes of physician effort for collecting, documenting, and analyzing the family history. While this is certainly better than the average of less than 2.5 minutes observed by Acheson et al,¹⁷ doctors would probably do it more if they were paid more for it.

Electronic solutions

Given that a lack of time is a barrier, what are some ways to minimize the time it takes to collect a family history?

With more physicians using electronic health records and with increasing use of Internet-based tools in the population at large, information-technology systems have been developed to help obtain the family history. One of the most widely used is the US surgeon general’s My Family Health Portrait, available free at https://familyhistory.hhs.gov. It is one of the broadest electronic family-history collection tools and has been validated for use in risk assessment for diabetes and cancer of the colon, breast, and ovaries.²²

However, electronic solutions have their own challenges. Not all patients have access to the Internet, many need help using these programs, and these tools may not work well with existing electronic medical records systems.²³ Ideally, these programs would also provide built-in decision support for the provider, thereby maximizing data use for final patient risk assessment.²³ Furthermore, electronic solutions are not a one-time-only risk assessment— periodic re-review of family history and reassessment of familial risk are required.²⁴

Does taking a family history improve outcomes? Lessons from breast cancer

One of the reasons physicians don’t get reimbursed for collecting a family history is that it has been difficult to measure any improvement in outcomes associated with risk prediction through family history.

The best examples of improvement in outcomes associated with family history-based risk prediction come from studies of breast cancer. From 5% to 10% of cases of breast cancer are part of hereditary cancer syndromes, many of which have a known genetic cause. The most prevalent of these genetic syndromes is the hereditary breast and ovarian cancer (HBOC) syndrome, caused by mutations in the breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) genes. Clinical testing for BRCA mutations has been available since 1998.²⁵ Women with a BRCA mutation have up to a 65% lifetime risk of developing breast cancer and up to a 40% lifetime risk of developing ovarian cancer.²⁶ Men with a BRCA mutation are at 10 to 100 times the risk of the general population (1% to 10% vs 0.1%) for developing breast cancer, and are also at higher risk of prostate and other cancers.²⁷

People who have a relative who developed breast cancer at a young age are more likely to harbor one of these mutations. For example, based on genetic testing in more than 185,000 people, the prevalence of BRCA mutations among people without cancer, not of Ashkenazi Jewish ancestry (a risk factor for breast cancer), and with no family history of early breast cancer or of ovarian cancer in any relative is 1.5%.²⁸ In contrast, people with no personal history of cancer who have a family history of breast cancer before age 50 have a 5.6% prevalence of BRCA mutation, and if they are of Ashkenazi Jewish ancestry, this number is 16.4%.²⁸

Medical and surgical interventions are available to reduce the risk of cancer in people with hereditary cancer syndromes such as HBOC. Options include screening more often, using advanced screening tests,²⁹ giving preventive drugs such as tamoxifen (Nolvadex), and prophylactic surgery.^30–32 What is the evidence that early screening and intervention in these people improve outcomes?

Domcheck et al³³ prospectively followed more than 2,400 women who had BRCA mutations to assess the effect of prophylactic mastectomy or salpingo-oophorectomy on cancer outcomes. Mastectomy was indeed associated with a lower risk of breast cancer: 0 cases of breast cancer were diagnosed in 3 years of prospective follow-up in the 247 women who elected to undergo mastectomy, compared with 98 cases diagnosed in the 1,372 women who did not elect it over a similar period.

Women who elected to undergo salpingo-oophorectomy had a similarly lower rate of ovarian cancer compared with those who did not elect surgery (1% vs 6%). Additionally, fewer women who elected prophylactic salpingo-oophorectomy died of any cause (3% vs 10%), died of breast cancer (2% vs 6%), or died of ovarian cancer (0.4% vs 3%) compared with women who did not elect surgery.

Taking a family history reduces costs

What is the evidence that appropriate use of the family history decreases health care costs? Let us continue with the example of HBOC syndrome due to BRCA mutations.

Given that germline mutations account for 5% to 10% of cases of breast cancer in the United States and that the women who develop cancer associated with such mutations do so at a relatively young age, these mutations account for a disproportionate share of life-years lost due to cancer.³⁴ Through taking a family history, these women at high risk can be identified and referred for genetic testing. Genetic testing, though costly, is more cost-effective than diagnosing and treating cancer.

Anderson et al,³⁴ in 2006, estimated that cost-effective policies on testing and preventive treatment for persons at high risk of breast cancer could save up to $800 million of the more than $8 billion spent each year on breast cancer diagnosis, prevention, and treatment.

Kwon et al,³⁵ in a simulation model (not a study in real patients), compared four different criteria for BRCA testing in women with ovarian cancer to see which strategy would be most cost-effective in preventing breast and ovarian cancers in their first-degree relatives. The best strategy, according to this analysis, is to test women with ovarian cancer for BRCA mutations if they also have a personal history of breast cancer, have a family history of breast or ovarian cancer, or are of Ashkenazi Jewish ancestry. The estimated cost per life-year gained with this strategy was $32,018, much lower than the widely accepted threshold for cost-effectiveness of $50,000 per life-year gained.

Although many professional organizations, including the US Preventive Services Task Force, have endorsed family-history-based eligibility criteria for genetic counseling and BRCA testing, awareness of the value of genetic testing in people who have been prescreened by family history has been relatively slow in seeping out to insurance carriers, especially Medicaid.^12,36 As evidence continues to accumulate showing that this approach can improve outcomes for at-risk family members, reimbursement and time allotted for obtaining and using the family history should be adjusted.

CHALLENGE 3: A KNOWLEDGE GAP IN CLINICIANS

Another challenge often cited as a cause of the underuse of the family history as a predictor of disease risk is that clinicians may not know enough about the topic. Several studies indicated that even when physicians had obtained some components of the family history, they did not document risk appropriately or recognize the significance of the pattern of inheritance observed.^37–39

In a study comparing primary care physicians and gastroenterologists in their use of the family history to predict the risk of hereditary colon cancer, gastroenterologists were more likely to elicit a family history of colorectal cancer and implement appropriate screening strategies, but overall compliance with screening guidelines was suboptimal in both groups.⁴⁰

A 2011 report by an advisory committee to the secretary of the US Department of Health and Human Services concluded that lack of genetics education in medical school limits the integration of genetics into clinical care.⁴¹

How can we close this knowledge gap?

Recognizing a need, the National Coalition for Health Professional Education in Genetics was established in 1996 by the American Medical Association, the American Nurses Association, and the National Human Genome Research Institute (www.nchpeg.org). Its mission is to promote the education of health professionals and access to information about advances in human genetics to improve the health care of the nation. It offers educational materials, including a newly updated “Core Principles in Family History” program, which can be used to educate medical providers and their patients about various concepts related to genetics and family history.

In addition, physicians can use many risk assessment tools based on family history in patient care. Two of the best known are:

• The Gail breast cancer risk assessment model, hosted by the National Cancer Institute (www.cancer.gov/bcrisktool/)
• The FRAX osteoporosis risk assessment model, developed by the World Health Organization (www.shef.ac.uk/FRAX).

As we continue to educate the medical community about the value of the family history in predicting disease, it will be important to increase efforts in medical schools and residency programs and to find new, more interactive ways of teaching these concepts.

A possible strategy is to highlight the use of pedigree drawing to recognize patterns of inheritance.² In a study of physician attitudes toward using patient-generated pedigrees in practice, such as those produced by the US surgeon general’s My Family Health Portrait, 73% of physicians stated that the patient-generated pedigree would improve their ability to assess the risk of disease, and the majority also agreed that it would not extend the time of the assessment.¹⁶

Is this information clinically useful?

Furthermore, knowing they are at risk might empower people and encourage them to engage with the medical system. For example, counseling people at risk of diabetes as reflected in the family history has been shown to increase their understanding of the risk and of preventive behaviors. Further study is needed to determine if such messages can engender lasting changes in behavior across many diseases.^42–46

TOWARD PERSONALIZED CARE

Especially now that caregivers are striving to provide value-based health care with emphasis on preventive care, the family history remains an important tool for detecting risk of disease. The evidence clearly indicates that medical providers have room for improvement in taking a family history and in using it.

We hope that asking patients about family history and recognizing patterns of disease will help us create personalized preventive-care plans, providing greater opportunity to educate and motivate our patients to work with us towards better health. Future solutions need to focus on time-effective ways to collect and analyze family history and on innovative methods of teaching medical providers at all levels to apply the family history to clinical practice.

At the dawn of the genomics era, is the family history still relevant? The answer is a resounding yes.^1,2

The family history is clinically useful because it is a proxy for genetic, environmental, and behavioral risks to health. It can be used to inform risk stratification, allowing for judicious use of screening and opening the door to early and even prophylactic treatment.^3–8 As people live longer, we will need to detect common chronic conditions early in their course so that we can continue to improve health outcomes. Family history can help physicians personalize preventive care for conditions such as diabetes, osteoporosis, and cancers of the breast, colon, and prostate.^2,9–15

However, there is ample evidence that the family history is underused. Most practitioners ask about it infrequently and inconsistently.^16,17 Why is this, and how can we encourage the use of this powerful tool to enhance our daily clinical practice and improve care?

We will discuss here some of the challenges that make it difficult for physicians to collect and use the family history in clinical practice, and review strategies for collecting and using the family history in a more consistent manner. We anticipate that this discussion will be helpful to clinicians, as the family history is an essential input to personalized, preventive care plans.

CHALLENGE 1: ARE PATIENTS’ REPORTS RELIABLE?

A question that often arises when discussing the utility of the family history is the reliability of patients’ reports. Can we trust that patients can accurately report their family history? For many conditions, the answer is yes.^18,19

Ziogas and Anton-Culverl²⁰ asked 1,111 cancer patients whether their relatives had ever had cancer and verified their answers. In more than 95% of cases, if the patient said that a first-degree or second-degree relative did not have cancer of any type, that relative truly did not have cancer. Overall, over-reporting of cancer was rare, occurring in 2.4% of cases.

If the patient said that a relative did have cancer, that statement was usually true as well. The reliability of a report of cancer in first-degree relatives was greater than 75% for most types of cancer (female breast, ovarian, esophageal, colorectal, pancreas, lung, melanoma, brain, thyroid, lymphoma, leukemia). For several of these types of cancer (female breast, colorectal, and brain), the reliability was 90% or higher. For second-degree relatives, the reliability of a reported positive history was moderate (50% to 80%) for the same types of cancer, and for third-degree relatives, the reliability dropped further for all types of cancer except female breast, brain, pancreas, and leukemia, for which the reliability of a positive report remained at 70%.

Wideroff et al²¹ had similar findings in a study of more than 1,000 patients and more than 20,000 of their relatives.

Yoon et al,¹⁸ at the US Centers for Disease Control and Prevention, developed a Web-based risk-assessment tool called Family Healthware, currently undergoing validation trials. They found that patients’ reports were highly reliable for coronary heart disease, stroke, diabetes, and breast, ovarian, and colorectal cancers. They also calculated the degree of risk associated with a positive family history and the prevalence of a family history of each of these diseases.

For the primary care physician, these studies support the reliability of patients’ reports and provide guidance for targeting specific conditions when obtaining a family history.

CHALLENGE 2: NO TIME OR REIMBURSEMENT

Perhaps the most obvious barriers to collecting a family history are lack of time and reimbursement.

Acheson et al,¹⁷ in an observational study of 138 primary care physicians and 4,454 patient visits, found that family history was discussed during 51% of new patient visits and 22% of established patient visits. The rate at which the family history was taken varied from 0% (some physicians never asked) to 81% of all patient visits. On average, physicians spent less than 2.5 minutes collecting the family history.

Not surprisingly, the family history was discussed more often at well-care visits than at illness visits, as the former type of visit tends to be longer and, by definition, to be spent partly on preventive care. A difficulty with this strategy is that, given the shortage of primary care physicians, limited access, and patient preference, most preventive-care visits are combined with problem-focused visits, further decreasing the time available to collect and discuss a family history. While some argue that the family history should routinely be obtained and discussed during preventive-care visits regardless of reimbursement and time, the reality is that it may simply drop on the list of priorities for each visit.

Rich et al³ estimated that taking a family history would increase reimbursement for only one new patient evaluation and management code (99202) and one return-visit code (99213) in Current Procedural Terminology. This action would increase reimbursement enough to support about 10 minutes of physician effort for collecting, documenting, and analyzing the family history. While this is certainly better than the average of less than 2.5 minutes observed by Acheson et al,¹⁷ doctors would probably do it more if they were paid more for it.

Electronic solutions

Given that a lack of time is a barrier, what are some ways to minimize the time it takes to collect a family history?

With more physicians using electronic health records and with increasing use of Internet-based tools in the population at large, information-technology systems have been developed to help obtain the family history. One of the most widely used is the US surgeon general’s My Family Health Portrait, available free at https://familyhistory.hhs.gov. It is one of the broadest electronic family-history collection tools and has been validated for use in risk assessment for diabetes and cancer of the colon, breast, and ovaries.²²

However, electronic solutions have their own challenges. Not all patients have access to the Internet, many need help using these programs, and these tools may not work well with existing electronic medical records systems.²³ Ideally, these programs would also provide built-in decision support for the provider, thereby maximizing data use for final patient risk assessment.²³ Furthermore, electronic solutions are not a one-time-only risk assessment— periodic re-review of family history and reassessment of familial risk are required.²⁴

Does taking a family history improve outcomes? Lessons from breast cancer

One of the reasons physicians don’t get reimbursed for collecting a family history is that it has been difficult to measure any improvement in outcomes associated with risk prediction through family history.

The best examples of improvement in outcomes associated with family history-based risk prediction come from studies of breast cancer. From 5% to 10% of cases of breast cancer are part of hereditary cancer syndromes, many of which have a known genetic cause. The most prevalent of these genetic syndromes is the hereditary breast and ovarian cancer (HBOC) syndrome, caused by mutations in the breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) genes. Clinical testing for BRCA mutations has been available since 1998.²⁵ Women with a BRCA mutation have up to a 65% lifetime risk of developing breast cancer and up to a 40% lifetime risk of developing ovarian cancer.²⁶ Men with a BRCA mutation are at 10 to 100 times the risk of the general population (1% to 10% vs 0.1%) for developing breast cancer, and are also at higher risk of prostate and other cancers.²⁷

People who have a relative who developed breast cancer at a young age are more likely to harbor one of these mutations. For example, based on genetic testing in more than 185,000 people, the prevalence of BRCA mutations among people without cancer, not of Ashkenazi Jewish ancestry (a risk factor for breast cancer), and with no family history of early breast cancer or of ovarian cancer in any relative is 1.5%.²⁸ In contrast, people with no personal history of cancer who have a family history of breast cancer before age 50 have a 5.6% prevalence of BRCA mutation, and if they are of Ashkenazi Jewish ancestry, this number is 16.4%.²⁸

Medical and surgical interventions are available to reduce the risk of cancer in people with hereditary cancer syndromes such as HBOC. Options include screening more often, using advanced screening tests,²⁹ giving preventive drugs such as tamoxifen (Nolvadex), and prophylactic surgery.^30–32 What is the evidence that early screening and intervention in these people improve outcomes?

Domcheck et al³³ prospectively followed more than 2,400 women who had BRCA mutations to assess the effect of prophylactic mastectomy or salpingo-oophorectomy on cancer outcomes. Mastectomy was indeed associated with a lower risk of breast cancer: 0 cases of breast cancer were diagnosed in 3 years of prospective follow-up in the 247 women who elected to undergo mastectomy, compared with 98 cases diagnosed in the 1,372 women who did not elect it over a similar period.

Women who elected to undergo salpingo-oophorectomy had a similarly lower rate of ovarian cancer compared with those who did not elect surgery (1% vs 6%). Additionally, fewer women who elected prophylactic salpingo-oophorectomy died of any cause (3% vs 10%), died of breast cancer (2% vs 6%), or died of ovarian cancer (0.4% vs 3%) compared with women who did not elect surgery.

Taking a family history reduces costs

What is the evidence that appropriate use of the family history decreases health care costs? Let us continue with the example of HBOC syndrome due to BRCA mutations.

Given that germline mutations account for 5% to 10% of cases of breast cancer in the United States and that the women who develop cancer associated with such mutations do so at a relatively young age, these mutations account for a disproportionate share of life-years lost due to cancer.³⁴ Through taking a family history, these women at high risk can be identified and referred for genetic testing. Genetic testing, though costly, is more cost-effective than diagnosing and treating cancer.

Anderson et al,³⁴ in 2006, estimated that cost-effective policies on testing and preventive treatment for persons at high risk of breast cancer could save up to $800 million of the more than $8 billion spent each year on breast cancer diagnosis, prevention, and treatment.

Kwon et al,³⁵ in a simulation model (not a study in real patients), compared four different criteria for BRCA testing in women with ovarian cancer to see which strategy would be most cost-effective in preventing breast and ovarian cancers in their first-degree relatives. The best strategy, according to this analysis, is to test women with ovarian cancer for BRCA mutations if they also have a personal history of breast cancer, have a family history of breast or ovarian cancer, or are of Ashkenazi Jewish ancestry. The estimated cost per life-year gained with this strategy was $32,018, much lower than the widely accepted threshold for cost-effectiveness of $50,000 per life-year gained.

Although many professional organizations, including the US Preventive Services Task Force, have endorsed family-history-based eligibility criteria for genetic counseling and BRCA testing, awareness of the value of genetic testing in people who have been prescreened by family history has been relatively slow in seeping out to insurance carriers, especially Medicaid.^12,36 As evidence continues to accumulate showing that this approach can improve outcomes for at-risk family members, reimbursement and time allotted for obtaining and using the family history should be adjusted.

CHALLENGE 3: A KNOWLEDGE GAP IN CLINICIANS

Another challenge often cited as a cause of the underuse of the family history as a predictor of disease risk is that clinicians may not know enough about the topic. Several studies indicated that even when physicians had obtained some components of the family history, they did not document risk appropriately or recognize the significance of the pattern of inheritance observed.^37–39

In a study comparing primary care physicians and gastroenterologists in their use of the family history to predict the risk of hereditary colon cancer, gastroenterologists were more likely to elicit a family history of colorectal cancer and implement appropriate screening strategies, but overall compliance with screening guidelines was suboptimal in both groups.⁴⁰

A 2011 report by an advisory committee to the secretary of the US Department of Health and Human Services concluded that lack of genetics education in medical school limits the integration of genetics into clinical care.⁴¹

How can we close this knowledge gap?

Recognizing a need, the National Coalition for Health Professional Education in Genetics was established in 1996 by the American Medical Association, the American Nurses Association, and the National Human Genome Research Institute (www.nchpeg.org). Its mission is to promote the education of health professionals and access to information about advances in human genetics to improve the health care of the nation. It offers educational materials, including a newly updated “Core Principles in Family History” program, which can be used to educate medical providers and their patients about various concepts related to genetics and family history.

In addition, physicians can use many risk assessment tools based on family history in patient care. Two of the best known are:

• The Gail breast cancer risk assessment model, hosted by the National Cancer Institute (www.cancer.gov/bcrisktool/)
• The FRAX osteoporosis risk assessment model, developed by the World Health Organization (www.shef.ac.uk/FRAX).

As we continue to educate the medical community about the value of the family history in predicting disease, it will be important to increase efforts in medical schools and residency programs and to find new, more interactive ways of teaching these concepts.

A possible strategy is to highlight the use of pedigree drawing to recognize patterns of inheritance.² In a study of physician attitudes toward using patient-generated pedigrees in practice, such as those produced by the US surgeon general’s My Family Health Portrait, 73% of physicians stated that the patient-generated pedigree would improve their ability to assess the risk of disease, and the majority also agreed that it would not extend the time of the assessment.¹⁶

Is this information clinically useful?

Furthermore, knowing they are at risk might empower people and encourage them to engage with the medical system. For example, counseling people at risk of diabetes as reflected in the family history has been shown to increase their understanding of the risk and of preventive behaviors. Further study is needed to determine if such messages can engender lasting changes in behavior across many diseases.^42–46

TOWARD PERSONALIZED CARE

Especially now that caregivers are striving to provide value-based health care with emphasis on preventive care, the family history remains an important tool for detecting risk of disease. The evidence clearly indicates that medical providers have room for improvement in taking a family history and in using it.

We hope that asking patients about family history and recognizing patterns of disease will help us create personalized preventive-care plans, providing greater opportunity to educate and motivate our patients to work with us towards better health. Future solutions need to focus on time-effective ways to collect and analyze family history and on innovative methods of teaching medical providers at all levels to apply the family history to clinical practice.

At the dawn of the genomics era, is the family history still relevant? The answer is a resounding yes.^1,2

The family history is clinically useful because it is a proxy for genetic, environmental, and behavioral risks to health. It can be used to inform risk stratification, allowing for judicious use of screening and opening the door to early and even prophylactic treatment.^3–8 As people live longer, we will need to detect common chronic conditions early in their course so that we can continue to improve health outcomes. Family history can help physicians personalize preventive care for conditions such as diabetes, osteoporosis, and cancers of the breast, colon, and prostate.^2,9–15

However, there is ample evidence that the family history is underused. Most practitioners ask about it infrequently and inconsistently.^16,17 Why is this, and how can we encourage the use of this powerful tool to enhance our daily clinical practice and improve care?

We will discuss here some of the challenges that make it difficult for physicians to collect and use the family history in clinical practice, and review strategies for collecting and using the family history in a more consistent manner. We anticipate that this discussion will be helpful to clinicians, as the family history is an essential input to personalized, preventive care plans.

CHALLENGE 1: ARE PATIENTS’ REPORTS RELIABLE?

A question that often arises when discussing the utility of the family history is the reliability of patients’ reports. Can we trust that patients can accurately report their family history? For many conditions, the answer is yes.^18,19

Ziogas and Anton-Culverl²⁰ asked 1,111 cancer patients whether their relatives had ever had cancer and verified their answers. In more than 95% of cases, if the patient said that a first-degree or second-degree relative did not have cancer of any type, that relative truly did not have cancer. Overall, over-reporting of cancer was rare, occurring in 2.4% of cases.

If the patient said that a relative did have cancer, that statement was usually true as well. The reliability of a report of cancer in first-degree relatives was greater than 75% for most types of cancer (female breast, ovarian, esophageal, colorectal, pancreas, lung, melanoma, brain, thyroid, lymphoma, leukemia). For several of these types of cancer (female breast, colorectal, and brain), the reliability was 90% or higher. For second-degree relatives, the reliability of a reported positive history was moderate (50% to 80%) for the same types of cancer, and for third-degree relatives, the reliability dropped further for all types of cancer except female breast, brain, pancreas, and leukemia, for which the reliability of a positive report remained at 70%.

Wideroff et al²¹ had similar findings in a study of more than 1,000 patients and more than 20,000 of their relatives.

Yoon et al,¹⁸ at the US Centers for Disease Control and Prevention, developed a Web-based risk-assessment tool called Family Healthware, currently undergoing validation trials. They found that patients’ reports were highly reliable for coronary heart disease, stroke, diabetes, and breast, ovarian, and colorectal cancers. They also calculated the degree of risk associated with a positive family history and the prevalence of a family history of each of these diseases.

For the primary care physician, these studies support the reliability of patients’ reports and provide guidance for targeting specific conditions when obtaining a family history.

CHALLENGE 2: NO TIME OR REIMBURSEMENT

Perhaps the most obvious barriers to collecting a family history are lack of time and reimbursement.

Acheson et al,¹⁷ in an observational study of 138 primary care physicians and 4,454 patient visits, found that family history was discussed during 51% of new patient visits and 22% of established patient visits. The rate at which the family history was taken varied from 0% (some physicians never asked) to 81% of all patient visits. On average, physicians spent less than 2.5 minutes collecting the family history.

Not surprisingly, the family history was discussed more often at well-care visits than at illness visits, as the former type of visit tends to be longer and, by definition, to be spent partly on preventive care. A difficulty with this strategy is that, given the shortage of primary care physicians, limited access, and patient preference, most preventive-care visits are combined with problem-focused visits, further decreasing the time available to collect and discuss a family history. While some argue that the family history should routinely be obtained and discussed during preventive-care visits regardless of reimbursement and time, the reality is that it may simply drop on the list of priorities for each visit.

Rich et al³ estimated that taking a family history would increase reimbursement for only one new patient evaluation and management code (99202) and one return-visit code (99213) in Current Procedural Terminology. This action would increase reimbursement enough to support about 10 minutes of physician effort for collecting, documenting, and analyzing the family history. While this is certainly better than the average of less than 2.5 minutes observed by Acheson et al,¹⁷ doctors would probably do it more if they were paid more for it.

Electronic solutions

Given that a lack of time is a barrier, what are some ways to minimize the time it takes to collect a family history?

With more physicians using electronic health records and with increasing use of Internet-based tools in the population at large, information-technology systems have been developed to help obtain the family history. One of the most widely used is the US surgeon general’s My Family Health Portrait, available free at https://familyhistory.hhs.gov. It is one of the broadest electronic family-history collection tools and has been validated for use in risk assessment for diabetes and cancer of the colon, breast, and ovaries.²²

However, electronic solutions have their own challenges. Not all patients have access to the Internet, many need help using these programs, and these tools may not work well with existing electronic medical records systems.²³ Ideally, these programs would also provide built-in decision support for the provider, thereby maximizing data use for final patient risk assessment.²³ Furthermore, electronic solutions are not a one-time-only risk assessment— periodic re-review of family history and reassessment of familial risk are required.²⁴

Does taking a family history improve outcomes? Lessons from breast cancer

One of the reasons physicians don’t get reimbursed for collecting a family history is that it has been difficult to measure any improvement in outcomes associated with risk prediction through family history.

The best examples of improvement in outcomes associated with family history-based risk prediction come from studies of breast cancer. From 5% to 10% of cases of breast cancer are part of hereditary cancer syndromes, many of which have a known genetic cause. The most prevalent of these genetic syndromes is the hereditary breast and ovarian cancer (HBOC) syndrome, caused by mutations in the breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) genes. Clinical testing for BRCA mutations has been available since 1998.²⁵ Women with a BRCA mutation have up to a 65% lifetime risk of developing breast cancer and up to a 40% lifetime risk of developing ovarian cancer.²⁶ Men with a BRCA mutation are at 10 to 100 times the risk of the general population (1% to 10% vs 0.1%) for developing breast cancer, and are also at higher risk of prostate and other cancers.²⁷

People who have a relative who developed breast cancer at a young age are more likely to harbor one of these mutations. For example, based on genetic testing in more than 185,000 people, the prevalence of BRCA mutations among people without cancer, not of Ashkenazi Jewish ancestry (a risk factor for breast cancer), and with no family history of early breast cancer or of ovarian cancer in any relative is 1.5%.²⁸ In contrast, people with no personal history of cancer who have a family history of breast cancer before age 50 have a 5.6% prevalence of BRCA mutation, and if they are of Ashkenazi Jewish ancestry, this number is 16.4%.²⁸

Medical and surgical interventions are available to reduce the risk of cancer in people with hereditary cancer syndromes such as HBOC. Options include screening more often, using advanced screening tests,²⁹ giving preventive drugs such as tamoxifen (Nolvadex), and prophylactic surgery.^30–32 What is the evidence that early screening and intervention in these people improve outcomes?

Domcheck et al³³ prospectively followed more than 2,400 women who had BRCA mutations to assess the effect of prophylactic mastectomy or salpingo-oophorectomy on cancer outcomes. Mastectomy was indeed associated with a lower risk of breast cancer: 0 cases of breast cancer were diagnosed in 3 years of prospective follow-up in the 247 women who elected to undergo mastectomy, compared with 98 cases diagnosed in the 1,372 women who did not elect it over a similar period.

Women who elected to undergo salpingo-oophorectomy had a similarly lower rate of ovarian cancer compared with those who did not elect surgery (1% vs 6%). Additionally, fewer women who elected prophylactic salpingo-oophorectomy died of any cause (3% vs 10%), died of breast cancer (2% vs 6%), or died of ovarian cancer (0.4% vs 3%) compared with women who did not elect surgery.

Taking a family history reduces costs

What is the evidence that appropriate use of the family history decreases health care costs? Let us continue with the example of HBOC syndrome due to BRCA mutations.

Given that germline mutations account for 5% to 10% of cases of breast cancer in the United States and that the women who develop cancer associated with such mutations do so at a relatively young age, these mutations account for a disproportionate share of life-years lost due to cancer.³⁴ Through taking a family history, these women at high risk can be identified and referred for genetic testing. Genetic testing, though costly, is more cost-effective than diagnosing and treating cancer.

Anderson et al,³⁴ in 2006, estimated that cost-effective policies on testing and preventive treatment for persons at high risk of breast cancer could save up to $800 million of the more than $8 billion spent each year on breast cancer diagnosis, prevention, and treatment.

Kwon et al,³⁵ in a simulation model (not a study in real patients), compared four different criteria for BRCA testing in women with ovarian cancer to see which strategy would be most cost-effective in preventing breast and ovarian cancers in their first-degree relatives. The best strategy, according to this analysis, is to test women with ovarian cancer for BRCA mutations if they also have a personal history of breast cancer, have a family history of breast or ovarian cancer, or are of Ashkenazi Jewish ancestry. The estimated cost per life-year gained with this strategy was $32,018, much lower than the widely accepted threshold for cost-effectiveness of $50,000 per life-year gained.

Although many professional organizations, including the US Preventive Services Task Force, have endorsed family-history-based eligibility criteria for genetic counseling and BRCA testing, awareness of the value of genetic testing in people who have been prescreened by family history has been relatively slow in seeping out to insurance carriers, especially Medicaid.^12,36 As evidence continues to accumulate showing that this approach can improve outcomes for at-risk family members, reimbursement and time allotted for obtaining and using the family history should be adjusted.

CHALLENGE 3: A KNOWLEDGE GAP IN CLINICIANS

Another challenge often cited as a cause of the underuse of the family history as a predictor of disease risk is that clinicians may not know enough about the topic. Several studies indicated that even when physicians had obtained some components of the family history, they did not document risk appropriately or recognize the significance of the pattern of inheritance observed.^37–39

In a study comparing primary care physicians and gastroenterologists in their use of the family history to predict the risk of hereditary colon cancer, gastroenterologists were more likely to elicit a family history of colorectal cancer and implement appropriate screening strategies, but overall compliance with screening guidelines was suboptimal in both groups.⁴⁰

A 2011 report by an advisory committee to the secretary of the US Department of Health and Human Services concluded that lack of genetics education in medical school limits the integration of genetics into clinical care.⁴¹

How can we close this knowledge gap?

Recognizing a need, the National Coalition for Health Professional Education in Genetics was established in 1996 by the American Medical Association, the American Nurses Association, and the National Human Genome Research Institute (www.nchpeg.org). Its mission is to promote the education of health professionals and access to information about advances in human genetics to improve the health care of the nation. It offers educational materials, including a newly updated “Core Principles in Family History” program, which can be used to educate medical providers and their patients about various concepts related to genetics and family history.

In addition, physicians can use many risk assessment tools based on family history in patient care. Two of the best known are:

• The Gail breast cancer risk assessment model, hosted by the National Cancer Institute (www.cancer.gov/bcrisktool/)
• The FRAX osteoporosis risk assessment model, developed by the World Health Organization (www.shef.ac.uk/FRAX).

As we continue to educate the medical community about the value of the family history in predicting disease, it will be important to increase efforts in medical schools and residency programs and to find new, more interactive ways of teaching these concepts.

A possible strategy is to highlight the use of pedigree drawing to recognize patterns of inheritance.² In a study of physician attitudes toward using patient-generated pedigrees in practice, such as those produced by the US surgeon general’s My Family Health Portrait, 73% of physicians stated that the patient-generated pedigree would improve their ability to assess the risk of disease, and the majority also agreed that it would not extend the time of the assessment.¹⁶

Is this information clinically useful?

Furthermore, knowing they are at risk might empower people and encourage them to engage with the medical system. For example, counseling people at risk of diabetes as reflected in the family history has been shown to increase their understanding of the risk and of preventive behaviors. Further study is needed to determine if such messages can engender lasting changes in behavior across many diseases.^42–46

TOWARD PERSONALIZED CARE

Especially now that caregivers are striving to provide value-based health care with emphasis on preventive care, the family history remains an important tool for detecting risk of disease. The evidence clearly indicates that medical providers have room for improvement in taking a family history and in using it.

We hope that asking patients about family history and recognizing patterns of disease will help us create personalized preventive-care plans, providing greater opportunity to educate and motivate our patients to work with us towards better health. Future solutions need to focus on time-effective ways to collect and analyze family history and on innovative methods of teaching medical providers at all levels to apply the family history to clinical practice.

The concept and promise of personalized health care have been anticipated for decades. Yet in its breadth and in the way we would like it practiced, it is in its infancy.

Personalized health care aims to individualize care by integrating a person’s unique clinical, molecular (ie, genetic, genomic), and environmental information. Applied not only when the patient is sick but also when he or she is well, it builds on and enhances our current standards of care.

As Sir William Osler recognized more than a century ago, “Variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under the abnormal conditions which we know as disease.”¹

PREDICTING THE RISK OF DISEASE

For years, we have attempted to predict and stratify the risk of disease, and the Human Genome Project has given us a new set of tools to help understand the complexity of disease and its variability.

We know and have known for decades—and in some cultures, for centuries—that family history is the most clinically validated tool for predicting the risk of disease.

Nevertheless, evidence suggests that we physicians are not collecting adequate family histories, and because of this, we are missing opportunities to intervene and prevent diseases predicted by the family history. The current standard of care is to use family medical histories to hone genetic differential diagnoses, and based on the differential diagnoses, to target specific genes to test in the setting of genetic counseling. Current genetic testing is used for molecular diagnoses and predictive testing so that gene-specific clinical management can be subsequently tailored.

PREDICTING RESPONSE TO TREATMENT

The use of personalized health care to predict response to treatment is a novel and constantly evolving practice.

ABO blood typing is a form of genetics-based personalization of safe transfusion that dates back to World War II.

A prominent, recent success story is in cancer treatment. For example, the American Society of Clinical Oncology now recommends that tumors from patients with node-negative, estrogen-receptor-positive breast cancer be evaluated with the Oncotype DX assay.² This test measures the expression of 21 genes, and the score obtained identifies patients most likely to benefit from adjuvant chemotherapy. A similar 12-gene expression signature has been developed for colon cancer, and others have been developed for hematologic cancers.^2,3 As with other new but apparently valid tests, the risk scores derived are sensitive at the extremes but ambiguous in the mid-ranges. We anticipate many more developments in this field.

In the field of pharmacogenomics, there is evidence to suggest that prior knowledge of CYP2C9 and VKORC1 genotypes enhances outcomes for patients starting treatment with warfarin. The US Food and Drug Administration revised the label on warfarin in February 2010, suggesting that genotypes be taken into consideration when the drug is prescribed.⁴

However, clinicians have been slow to adopt genotype testing when prescribing warfarin. Some cite the paucity of large, randomized, controlled trials demonstrating clinical utility of genotype-informed prescribing. Others cite concern that warfarin will soon become obsolete with the arrival of newer anticoagulants (such as factor X inhibitors) that do not carry warfarin’s adverse effects, and these genotypes will therefore become moot. Perhaps, as we move forward and new drugs are developed, companion genotype tests could be developed at the same time to be used with them.⁵

IMPROVING CARE, SAVING MONEY, AND EMPOWERING PATIENTS

The goal of personalized health care, by customizing treatments (medication types and dosages) and preventive strategies, is to optimize medical care and improve outcomes for each patient. It could improve the quality of care by targeting interventions and reducing adverse events, topics that are important to all of us in the current environment of health care reform.

A personalized approach might also, in the long run, decrease the cost of health care by driving appropriate utilization of resources.

Lastly, the true value of personalized health care may be in its potential to improve patient satisfaction and to empower our patients to work with us towards better health.

WE LAUNCH A NEW SERIES

To keep physicians up-to-date on progress in personalized health care, the Cleveland Clinic Journal of Medicine will present a series of articles on the topic. The series, to run once a quarter, begins in this issue, on page 331, with an article on the importance of the family history as a piece of genetic information that can help to predict the risk of disease and inform preventive care plans. Future topics will include the role of genetics and genomics in personalized care of patients with breast and colorectal cancers; the genetic counselor as a part of the health care team; pharmacogenomics; and ethical, legal, and societal considerations.

Our goal in this series is to provide practical information to help our readers incorporate personalized approaches into daily practice. In addition, as patients become more interested in and informed about personalized health care, we hope this information will help clinicians to effectively coach them about its potential benefits and risks. We also hope this information will enable our readers to ask the right questions so that patient and health care provider can work together to help the patient grow old gracefully.

As the series unfolds, we ask you to send us feedback and to suggest other topics in personalized health care you would like us to cover in this series.

The concept and promise of personalized health care have been anticipated for decades. Yet in its breadth and in the way we would like it practiced, it is in its infancy.

Personalized health care aims to individualize care by integrating a person’s unique clinical, molecular (ie, genetic, genomic), and environmental information. Applied not only when the patient is sick but also when he or she is well, it builds on and enhances our current standards of care.

As Sir William Osler recognized more than a century ago, “Variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under the abnormal conditions which we know as disease.”¹

PREDICTING THE RISK OF DISEASE

For years, we have attempted to predict and stratify the risk of disease, and the Human Genome Project has given us a new set of tools to help understand the complexity of disease and its variability.

We know and have known for decades—and in some cultures, for centuries—that family history is the most clinically validated tool for predicting the risk of disease.

Nevertheless, evidence suggests that we physicians are not collecting adequate family histories, and because of this, we are missing opportunities to intervene and prevent diseases predicted by the family history. The current standard of care is to use family medical histories to hone genetic differential diagnoses, and based on the differential diagnoses, to target specific genes to test in the setting of genetic counseling. Current genetic testing is used for molecular diagnoses and predictive testing so that gene-specific clinical management can be subsequently tailored.

PREDICTING RESPONSE TO TREATMENT

The use of personalized health care to predict response to treatment is a novel and constantly evolving practice.

ABO blood typing is a form of genetics-based personalization of safe transfusion that dates back to World War II.

A prominent, recent success story is in cancer treatment. For example, the American Society of Clinical Oncology now recommends that tumors from patients with node-negative, estrogen-receptor-positive breast cancer be evaluated with the Oncotype DX assay.² This test measures the expression of 21 genes, and the score obtained identifies patients most likely to benefit from adjuvant chemotherapy. A similar 12-gene expression signature has been developed for colon cancer, and others have been developed for hematologic cancers.^2,3 As with other new but apparently valid tests, the risk scores derived are sensitive at the extremes but ambiguous in the mid-ranges. We anticipate many more developments in this field.

In the field of pharmacogenomics, there is evidence to suggest that prior knowledge of CYP2C9 and VKORC1 genotypes enhances outcomes for patients starting treatment with warfarin. The US Food and Drug Administration revised the label on warfarin in February 2010, suggesting that genotypes be taken into consideration when the drug is prescribed.⁴

However, clinicians have been slow to adopt genotype testing when prescribing warfarin. Some cite the paucity of large, randomized, controlled trials demonstrating clinical utility of genotype-informed prescribing. Others cite concern that warfarin will soon become obsolete with the arrival of newer anticoagulants (such as factor X inhibitors) that do not carry warfarin’s adverse effects, and these genotypes will therefore become moot. Perhaps, as we move forward and new drugs are developed, companion genotype tests could be developed at the same time to be used with them.⁵

IMPROVING CARE, SAVING MONEY, AND EMPOWERING PATIENTS

The goal of personalized health care, by customizing treatments (medication types and dosages) and preventive strategies, is to optimize medical care and improve outcomes for each patient. It could improve the quality of care by targeting interventions and reducing adverse events, topics that are important to all of us in the current environment of health care reform.

A personalized approach might also, in the long run, decrease the cost of health care by driving appropriate utilization of resources.

Lastly, the true value of personalized health care may be in its potential to improve patient satisfaction and to empower our patients to work with us towards better health.

WE LAUNCH A NEW SERIES

To keep physicians up-to-date on progress in personalized health care, the Cleveland Clinic Journal of Medicine will present a series of articles on the topic. The series, to run once a quarter, begins in this issue, on page 331, with an article on the importance of the family history as a piece of genetic information that can help to predict the risk of disease and inform preventive care plans. Future topics will include the role of genetics and genomics in personalized care of patients with breast and colorectal cancers; the genetic counselor as a part of the health care team; pharmacogenomics; and ethical, legal, and societal considerations.

Our goal in this series is to provide practical information to help our readers incorporate personalized approaches into daily practice. In addition, as patients become more interested in and informed about personalized health care, we hope this information will help clinicians to effectively coach them about its potential benefits and risks. We also hope this information will enable our readers to ask the right questions so that patient and health care provider can work together to help the patient grow old gracefully.

As the series unfolds, we ask you to send us feedback and to suggest other topics in personalized health care you would like us to cover in this series.

The concept and promise of personalized health care have been anticipated for decades. Yet in its breadth and in the way we would like it practiced, it is in its infancy.

Personalized health care aims to individualize care by integrating a person’s unique clinical, molecular (ie, genetic, genomic), and environmental information. Applied not only when the patient is sick but also when he or she is well, it builds on and enhances our current standards of care.

As Sir William Osler recognized more than a century ago, “Variability is the law of life, and as no two faces are the same, so no two bodies are alike, and no two individuals react alike and behave alike under the abnormal conditions which we know as disease.”¹

PREDICTING THE RISK OF DISEASE

For years, we have attempted to predict and stratify the risk of disease, and the Human Genome Project has given us a new set of tools to help understand the complexity of disease and its variability.

We know and have known for decades—and in some cultures, for centuries—that family history is the most clinically validated tool for predicting the risk of disease.

Nevertheless, evidence suggests that we physicians are not collecting adequate family histories, and because of this, we are missing opportunities to intervene and prevent diseases predicted by the family history. The current standard of care is to use family medical histories to hone genetic differential diagnoses, and based on the differential diagnoses, to target specific genes to test in the setting of genetic counseling. Current genetic testing is used for molecular diagnoses and predictive testing so that gene-specific clinical management can be subsequently tailored.

PREDICTING RESPONSE TO TREATMENT

The use of personalized health care to predict response to treatment is a novel and constantly evolving practice.

ABO blood typing is a form of genetics-based personalization of safe transfusion that dates back to World War II.

A prominent, recent success story is in cancer treatment. For example, the American Society of Clinical Oncology now recommends that tumors from patients with node-negative, estrogen-receptor-positive breast cancer be evaluated with the Oncotype DX assay.² This test measures the expression of 21 genes, and the score obtained identifies patients most likely to benefit from adjuvant chemotherapy. A similar 12-gene expression signature has been developed for colon cancer, and others have been developed for hematologic cancers.^2,3 As with other new but apparently valid tests, the risk scores derived are sensitive at the extremes but ambiguous in the mid-ranges. We anticipate many more developments in this field.

In the field of pharmacogenomics, there is evidence to suggest that prior knowledge of CYP2C9 and VKORC1 genotypes enhances outcomes for patients starting treatment with warfarin. The US Food and Drug Administration revised the label on warfarin in February 2010, suggesting that genotypes be taken into consideration when the drug is prescribed.⁴

However, clinicians have been slow to adopt genotype testing when prescribing warfarin. Some cite the paucity of large, randomized, controlled trials demonstrating clinical utility of genotype-informed prescribing. Others cite concern that warfarin will soon become obsolete with the arrival of newer anticoagulants (such as factor X inhibitors) that do not carry warfarin’s adverse effects, and these genotypes will therefore become moot. Perhaps, as we move forward and new drugs are developed, companion genotype tests could be developed at the same time to be used with them.⁵

IMPROVING CARE, SAVING MONEY, AND EMPOWERING PATIENTS

The goal of personalized health care, by customizing treatments (medication types and dosages) and preventive strategies, is to optimize medical care and improve outcomes for each patient. It could improve the quality of care by targeting interventions and reducing adverse events, topics that are important to all of us in the current environment of health care reform.

A personalized approach might also, in the long run, decrease the cost of health care by driving appropriate utilization of resources.

Lastly, the true value of personalized health care may be in its potential to improve patient satisfaction and to empower our patients to work with us towards better health.

WE LAUNCH A NEW SERIES

To keep physicians up-to-date on progress in personalized health care, the Cleveland Clinic Journal of Medicine will present a series of articles on the topic. The series, to run once a quarter, begins in this issue, on page 331, with an article on the importance of the family history as a piece of genetic information that can help to predict the risk of disease and inform preventive care plans. Future topics will include the role of genetics and genomics in personalized care of patients with breast and colorectal cancers; the genetic counselor as a part of the health care team; pharmacogenomics; and ethical, legal, and societal considerations.

Our goal in this series is to provide practical information to help our readers incorporate personalized approaches into daily practice. In addition, as patients become more interested in and informed about personalized health care, we hope this information will help clinicians to effectively coach them about its potential benefits and risks. We also hope this information will enable our readers to ask the right questions so that patient and health care provider can work together to help the patient grow old gracefully.

As the series unfolds, we ask you to send us feedback and to suggest other topics in personalized health care you would like us to cover in this series.