Kevin Y. Kane, MD

BACKGROUND: Expert panels recommend several different screening regimens for colorectal cancer (CRC), including annual fecal occult blood testing, sigmoidoscopy every 5 years, annual fecal occult blood testing plus flexible sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years. All of these tests vary considerably with respect to performance characteristics, complication rates, acceptability, and cost. Only fecal occult blood testing has been studied in a randomized controlled trial to establish effectiveness. This article compares the cost and effectiveness of CRC screening methods.

POPULATION STUDIED: The authors used a hypothetical population of men and women (white and black) aged 50 years and at average risk for colon cancer. They were placed in health categories defined by the presence or absence of a colon polyp or cancer. The categories were reassigned to simulate the natural progression of colon cancer on the basis of probabilities from studies and data from the Surveillance Epidemiology and End Results (SEER) program.

STUDY DESIGN AND VALIDITY: This study used a Markov model to simulate the evolution of normal epithelium in the colon to an adenomatous polyp and progression to malignancy. The screening mechanisms that allowed detection, removal of a polyp, and treatment of cancer were compared. Screening started at age 50 years and continued until age 85 years. Incremental analysis by rank ordering the strategies allowed methods of increasing effectiveness to dominate those methods that were more costly and less effective. Test and treatment costs were obtained from an health maintenance organization study population. Based on previous studies, an expected compliance rate of 60% was used to estimate the cost-effectiveness of screening tests. Sensitivity analysis was done to measure test performance when parameters such as test cost, sensitivity, specificity, and compliance rates were altered.

OUTCOMES MEASURED: The outcomes measured include cost-effectiveness of colorectal screening methods, life expectancy, and CRC incidence and mortality.

RESULTS: The reported results were for white men only. All CRC screening tests resulted in a reduced incidence of cancer and decreased mortality from CRC. Theoretically, the most effective test to screen for CRC is the annual rehydrated fecal occult blood test plus sigmoidoscopy every 5 years. This method has a cost-effectiveness ratio of $92,900 for each year of life saved. This compares similarly to the cost-effectiveness of screening Papanicolaou tests and mammograms. This method also resulted in a 60% reduction in the incidence of CRC and an 80% reduction in CRC mortality. Interestingly, the cost of this method became prohibitive if the model used a 100% compliance rate instead of 60%. Colonoscopy every 5 years is more effective than rehydrated fecal occult blood testing plus sigmoidoscopy every 5 years but is cost prohibitive. If the price of colonoscopy could be reduced by 25%, colonoscopy every 10 years would be a viable option. Annual rehydrated fecal occult blood testing alone shows a 65% reduction in CRC mortality, while dry cards only show a 55% reduction. The longer life expectancy of women and the higher cancer mortality in African Americans may make CRC screening even more cost-effective in these groups.

BACKGROUND: Expert panels recommend several different screening regimens for colorectal cancer (CRC), including annual fecal occult blood testing, sigmoidoscopy every 5 years, annual fecal occult blood testing plus flexible sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years. All of these tests vary considerably with respect to performance characteristics, complication rates, acceptability, and cost. Only fecal occult blood testing has been studied in a randomized controlled trial to establish effectiveness. This article compares the cost and effectiveness of CRC screening methods.

POPULATION STUDIED: The authors used a hypothetical population of men and women (white and black) aged 50 years and at average risk for colon cancer. They were placed in health categories defined by the presence or absence of a colon polyp or cancer. The categories were reassigned to simulate the natural progression of colon cancer on the basis of probabilities from studies and data from the Surveillance Epidemiology and End Results (SEER) program.

STUDY DESIGN AND VALIDITY: This study used a Markov model to simulate the evolution of normal epithelium in the colon to an adenomatous polyp and progression to malignancy. The screening mechanisms that allowed detection, removal of a polyp, and treatment of cancer were compared. Screening started at age 50 years and continued until age 85 years. Incremental analysis by rank ordering the strategies allowed methods of increasing effectiveness to dominate those methods that were more costly and less effective. Test and treatment costs were obtained from an health maintenance organization study population. Based on previous studies, an expected compliance rate of 60% was used to estimate the cost-effectiveness of screening tests. Sensitivity analysis was done to measure test performance when parameters such as test cost, sensitivity, specificity, and compliance rates were altered.

OUTCOMES MEASURED: The outcomes measured include cost-effectiveness of colorectal screening methods, life expectancy, and CRC incidence and mortality.

RESULTS: The reported results were for white men only. All CRC screening tests resulted in a reduced incidence of cancer and decreased mortality from CRC. Theoretically, the most effective test to screen for CRC is the annual rehydrated fecal occult blood test plus sigmoidoscopy every 5 years. This method has a cost-effectiveness ratio of $92,900 for each year of life saved. This compares similarly to the cost-effectiveness of screening Papanicolaou tests and mammograms. This method also resulted in a 60% reduction in the incidence of CRC and an 80% reduction in CRC mortality. Interestingly, the cost of this method became prohibitive if the model used a 100% compliance rate instead of 60%. Colonoscopy every 5 years is more effective than rehydrated fecal occult blood testing plus sigmoidoscopy every 5 years but is cost prohibitive. If the price of colonoscopy could be reduced by 25%, colonoscopy every 10 years would be a viable option. Annual rehydrated fecal occult blood testing alone shows a 65% reduction in CRC mortality, while dry cards only show a 55% reduction. The longer life expectancy of women and the higher cancer mortality in African Americans may make CRC screening even more cost-effective in these groups.

BACKGROUND: Expert panels recommend several different screening regimens for colorectal cancer (CRC), including annual fecal occult blood testing, sigmoidoscopy every 5 years, annual fecal occult blood testing plus flexible sigmoidoscopy every 5 years, double contrast barium enema every 5 years, and colonoscopy every 10 years. All of these tests vary considerably with respect to performance characteristics, complication rates, acceptability, and cost. Only fecal occult blood testing has been studied in a randomized controlled trial to establish effectiveness. This article compares the cost and effectiveness of CRC screening methods.

POPULATION STUDIED: The authors used a hypothetical population of men and women (white and black) aged 50 years and at average risk for colon cancer. They were placed in health categories defined by the presence or absence of a colon polyp or cancer. The categories were reassigned to simulate the natural progression of colon cancer on the basis of probabilities from studies and data from the Surveillance Epidemiology and End Results (SEER) program.

STUDY DESIGN AND VALIDITY: This study used a Markov model to simulate the evolution of normal epithelium in the colon to an adenomatous polyp and progression to malignancy. The screening mechanisms that allowed detection, removal of a polyp, and treatment of cancer were compared. Screening started at age 50 years and continued until age 85 years. Incremental analysis by rank ordering the strategies allowed methods of increasing effectiveness to dominate those methods that were more costly and less effective. Test and treatment costs were obtained from an health maintenance organization study population. Based on previous studies, an expected compliance rate of 60% was used to estimate the cost-effectiveness of screening tests. Sensitivity analysis was done to measure test performance when parameters such as test cost, sensitivity, specificity, and compliance rates were altered.

OUTCOMES MEASURED: The outcomes measured include cost-effectiveness of colorectal screening methods, life expectancy, and CRC incidence and mortality.

RESULTS: The reported results were for white men only. All CRC screening tests resulted in a reduced incidence of cancer and decreased mortality from CRC. Theoretically, the most effective test to screen for CRC is the annual rehydrated fecal occult blood test plus sigmoidoscopy every 5 years. This method has a cost-effectiveness ratio of $92,900 for each year of life saved. This compares similarly to the cost-effectiveness of screening Papanicolaou tests and mammograms. This method also resulted in a 60% reduction in the incidence of CRC and an 80% reduction in CRC mortality. Interestingly, the cost of this method became prohibitive if the model used a 100% compliance rate instead of 60%. Colonoscopy every 5 years is more effective than rehydrated fecal occult blood testing plus sigmoidoscopy every 5 years but is cost prohibitive. If the price of colonoscopy could be reduced by 25%, colonoscopy every 10 years would be a viable option. Annual rehydrated fecal occult blood testing alone shows a 65% reduction in CRC mortality, while dry cards only show a 55% reduction. The longer life expectancy of women and the higher cancer mortality in African Americans may make CRC screening even more cost-effective in these groups.

BACKGROUND: Annual screening mammography is universally accepted as the standard of care in the United States for woman 50 years and older. Although evidence supports screening as effective in reducing breast cancer mortality, it is not known whether mammography plus a clinical breast examination (CBE) is more effective at reducing cancer mortality than a thorough CBE alone.

POPULATION STUDIED: A total of 39,459 Canadian women 50 to 59 years were recruited through general publicity, mailings, and physician referral. These women had not received a mammogram in the previous year and did not have a history of breast cancer.

STUDY DESIGN AND VALIDITY: The women were randomized to receive either 5 annual CBEs with mammography or a CBE alone annually for 5 years. Well-trained nurses using a visual inspection component and palpation in a radial pattern performed most of the breast examinations. Physicians performed the others. The examinations were very thorough and took approximately 10 minutes. Patients were also taught breast self-examination. Two-view mammograms were used and independently reviewed. Patients with abnormal findings were referred to the Canadian National Breast Screening Study (CNBSS) clinic for further evaluation by a surgeon. Breast cancers were identified through the CNBSS centers and the National Cancer Registry during the 13-year follow-up. The cause of death was identified through the participant’s family members, physicians, and the Canadian Mortality Data Base. Overall the study appeared valid. The 2 randomized groups seemed equal for breast cancer risk factors and other demographics. There was excellent follow-up and good compliance within each group. Randomization was not concealed. Previous scrutiny of this study centered on a change in mammography technique during the screening. Further analysis showed high sensitivity and expected cancer detection rates despite this change. The article does not mention what types of screening the participants underwent after the initial 5-year study period. This could potentially have an effect on the mortality numbers, if women decided to stop their screening after the study period ended. This study did not address differences in quality of life, such as discomfort from mammograms and additional procedures from false-positive screenings.

OUTCOMES MEASURED: Breast cancer mortality was the primary outcome. The tumor size and number of lymph node–positive cancers were also reported.

RESULTS: Only 54 of the original participants were excluded from the analysis. At the 13-year follow-up there were 107 breast cancer deaths in the combined mammography plus CBE group and 105 deaths in the CBE-only group (rate ratio=1.02; 95% confidence interval, 0.78-1.33). A total of 622 invasive and 71 in situ cancers were found in the combined group and 610 invasive and 16 in situ cancers were identified in the CBE-only group. Mammography was able to detect a cancer 2.1 years earlier than CBE alone. However, this lead time did not appear to improve survival. Overall, the tumors identified by mammography were smaller. There was no significant difference between the 2 groups in the number of lymph node–positive cancers detected by the end of the study. As expected, there were approximately 3 times as many biopsies and more diagnostic tests performed in the mammogram group.

BACKGROUND: Annual screening mammography is universally accepted as the standard of care in the United States for woman 50 years and older. Although evidence supports screening as effective in reducing breast cancer mortality, it is not known whether mammography plus a clinical breast examination (CBE) is more effective at reducing cancer mortality than a thorough CBE alone.

POPULATION STUDIED: A total of 39,459 Canadian women 50 to 59 years were recruited through general publicity, mailings, and physician referral. These women had not received a mammogram in the previous year and did not have a history of breast cancer.

STUDY DESIGN AND VALIDITY: The women were randomized to receive either 5 annual CBEs with mammography or a CBE alone annually for 5 years. Well-trained nurses using a visual inspection component and palpation in a radial pattern performed most of the breast examinations. Physicians performed the others. The examinations were very thorough and took approximately 10 minutes. Patients were also taught breast self-examination. Two-view mammograms were used and independently reviewed. Patients with abnormal findings were referred to the Canadian National Breast Screening Study (CNBSS) clinic for further evaluation by a surgeon. Breast cancers were identified through the CNBSS centers and the National Cancer Registry during the 13-year follow-up. The cause of death was identified through the participant’s family members, physicians, and the Canadian Mortality Data Base. Overall the study appeared valid. The 2 randomized groups seemed equal for breast cancer risk factors and other demographics. There was excellent follow-up and good compliance within each group. Randomization was not concealed. Previous scrutiny of this study centered on a change in mammography technique during the screening. Further analysis showed high sensitivity and expected cancer detection rates despite this change. The article does not mention what types of screening the participants underwent after the initial 5-year study period. This could potentially have an effect on the mortality numbers, if women decided to stop their screening after the study period ended. This study did not address differences in quality of life, such as discomfort from mammograms and additional procedures from false-positive screenings.

OUTCOMES MEASURED: Breast cancer mortality was the primary outcome. The tumor size and number of lymph node–positive cancers were also reported.

RESULTS: Only 54 of the original participants were excluded from the analysis. At the 13-year follow-up there were 107 breast cancer deaths in the combined mammography plus CBE group and 105 deaths in the CBE-only group (rate ratio=1.02; 95% confidence interval, 0.78-1.33). A total of 622 invasive and 71 in situ cancers were found in the combined group and 610 invasive and 16 in situ cancers were identified in the CBE-only group. Mammography was able to detect a cancer 2.1 years earlier than CBE alone. However, this lead time did not appear to improve survival. Overall, the tumors identified by mammography were smaller. There was no significant difference between the 2 groups in the number of lymph node–positive cancers detected by the end of the study. As expected, there were approximately 3 times as many biopsies and more diagnostic tests performed in the mammogram group.

BACKGROUND: Annual screening mammography is universally accepted as the standard of care in the United States for woman 50 years and older. Although evidence supports screening as effective in reducing breast cancer mortality, it is not known whether mammography plus a clinical breast examination (CBE) is more effective at reducing cancer mortality than a thorough CBE alone.

POPULATION STUDIED: A total of 39,459 Canadian women 50 to 59 years were recruited through general publicity, mailings, and physician referral. These women had not received a mammogram in the previous year and did not have a history of breast cancer.

STUDY DESIGN AND VALIDITY: The women were randomized to receive either 5 annual CBEs with mammography or a CBE alone annually for 5 years. Well-trained nurses using a visual inspection component and palpation in a radial pattern performed most of the breast examinations. Physicians performed the others. The examinations were very thorough and took approximately 10 minutes. Patients were also taught breast self-examination. Two-view mammograms were used and independently reviewed. Patients with abnormal findings were referred to the Canadian National Breast Screening Study (CNBSS) clinic for further evaluation by a surgeon. Breast cancers were identified through the CNBSS centers and the National Cancer Registry during the 13-year follow-up. The cause of death was identified through the participant’s family members, physicians, and the Canadian Mortality Data Base. Overall the study appeared valid. The 2 randomized groups seemed equal for breast cancer risk factors and other demographics. There was excellent follow-up and good compliance within each group. Randomization was not concealed. Previous scrutiny of this study centered on a change in mammography technique during the screening. Further analysis showed high sensitivity and expected cancer detection rates despite this change. The article does not mention what types of screening the participants underwent after the initial 5-year study period. This could potentially have an effect on the mortality numbers, if women decided to stop their screening after the study period ended. This study did not address differences in quality of life, such as discomfort from mammograms and additional procedures from false-positive screenings.

OUTCOMES MEASURED: Breast cancer mortality was the primary outcome. The tumor size and number of lymph node–positive cancers were also reported.

RESULTS: Only 54 of the original participants were excluded from the analysis. At the 13-year follow-up there were 107 breast cancer deaths in the combined mammography plus CBE group and 105 deaths in the CBE-only group (rate ratio=1.02; 95% confidence interval, 0.78-1.33). A total of 622 invasive and 71 in situ cancers were found in the combined group and 610 invasive and 16 in situ cancers were identified in the CBE-only group. Mammography was able to detect a cancer 2.1 years earlier than CBE alone. However, this lead time did not appear to improve survival. Overall, the tumors identified by mammography were smaller. There was no significant difference between the 2 groups in the number of lymph node–positive cancers detected by the end of the study. As expected, there were approximately 3 times as many biopsies and more diagnostic tests performed in the mammogram group.

BACKGROUND: An estimated 175,000 Americans have a pulmonary embolism (PE) each year. Pulmonary angiography is the accepted gold standard for diagnosing PE, but it is invasive, expensive, and causes cardiopulmonary complications in 3% to 4% of patients. A ventilation-perfusion (V/Q) scan is less invasive, but also less accurate. Used in combination with clinical assessment, it fails to find 20% of PEs.¹ Recent studies evaluating the use of spiral computed tomography (CT) have reported favorable results in diagnosing PE. However, the role of CT for this use is not yet fully defined.

POPULATION STUDIED: In this systematic review, neither specific patient characteristics nor exclusion criteria were mentioned. Enrollment criteria were described as inconsistent.

STUDY DESIGN AND VALIDITY: The authors conducted a systematic review of the literature evaluating the use of spiral CT in diagnosing PE. They searched MEDLINE and Current Contents through July 1998 and reviewed pertinent references. Eleven articles met their preset inclusion criteria. The articles were rated by using a set of 11 basic methodologic standards for addressing diagnostic test research. None of the 11 studies met all of the criteria; only 5 studies met 5 or more criteria. All studies compared CT with either pulmonary angiography or another reference standard (high-probability V/Q scan plus high clinical suspicion) to confirm the diagnosis of PE. The studies were not methodologically similar enough to perform a meta-analysis.

OUTCOMES MEASURED: The primary outcome was the presence of a PE.

RESULTS: Compared with the gold standard of pulmonary angiography, the sensitivity of spiral CT ranged from 64% to 93%. If a PE is present, the probability of a positive CT scan is 64% to 93%. That means up to one third of PEs could be missed. The reported specificity ranged from 89% to 100%, which corresponds to a false-positive rate of 0% to 11%. These results are similar to those of another recent systematic review in which the authors reported a sensitivity range of 53% to 100% and a specificity range of 81% to 100%.¹ Nine of the studies differentiated between large central and small subsegmental vessel embolism. When stratified by site, the sensitivity for spiral CT was much higher for central vessel PE (83% to 100%) than for subsegmental vessel PE (29%).

BACKGROUND: An estimated 175,000 Americans have a pulmonary embolism (PE) each year. Pulmonary angiography is the accepted gold standard for diagnosing PE, but it is invasive, expensive, and causes cardiopulmonary complications in 3% to 4% of patients. A ventilation-perfusion (V/Q) scan is less invasive, but also less accurate. Used in combination with clinical assessment, it fails to find 20% of PEs.¹ Recent studies evaluating the use of spiral computed tomography (CT) have reported favorable results in diagnosing PE. However, the role of CT for this use is not yet fully defined.

POPULATION STUDIED: In this systematic review, neither specific patient characteristics nor exclusion criteria were mentioned. Enrollment criteria were described as inconsistent.

STUDY DESIGN AND VALIDITY: The authors conducted a systematic review of the literature evaluating the use of spiral CT in diagnosing PE. They searched MEDLINE and Current Contents through July 1998 and reviewed pertinent references. Eleven articles met their preset inclusion criteria. The articles were rated by using a set of 11 basic methodologic standards for addressing diagnostic test research. None of the 11 studies met all of the criteria; only 5 studies met 5 or more criteria. All studies compared CT with either pulmonary angiography or another reference standard (high-probability V/Q scan plus high clinical suspicion) to confirm the diagnosis of PE. The studies were not methodologically similar enough to perform a meta-analysis.

OUTCOMES MEASURED: The primary outcome was the presence of a PE.

RESULTS: Compared with the gold standard of pulmonary angiography, the sensitivity of spiral CT ranged from 64% to 93%. If a PE is present, the probability of a positive CT scan is 64% to 93%. That means up to one third of PEs could be missed. The reported specificity ranged from 89% to 100%, which corresponds to a false-positive rate of 0% to 11%. These results are similar to those of another recent systematic review in which the authors reported a sensitivity range of 53% to 100% and a specificity range of 81% to 100%.¹ Nine of the studies differentiated between large central and small subsegmental vessel embolism. When stratified by site, the sensitivity for spiral CT was much higher for central vessel PE (83% to 100%) than for subsegmental vessel PE (29%).

BACKGROUND: An estimated 175,000 Americans have a pulmonary embolism (PE) each year. Pulmonary angiography is the accepted gold standard for diagnosing PE, but it is invasive, expensive, and causes cardiopulmonary complications in 3% to 4% of patients. A ventilation-perfusion (V/Q) scan is less invasive, but also less accurate. Used in combination with clinical assessment, it fails to find 20% of PEs.¹ Recent studies evaluating the use of spiral computed tomography (CT) have reported favorable results in diagnosing PE. However, the role of CT for this use is not yet fully defined.

POPULATION STUDIED: In this systematic review, neither specific patient characteristics nor exclusion criteria were mentioned. Enrollment criteria were described as inconsistent.

STUDY DESIGN AND VALIDITY: The authors conducted a systematic review of the literature evaluating the use of spiral CT in diagnosing PE. They searched MEDLINE and Current Contents through July 1998 and reviewed pertinent references. Eleven articles met their preset inclusion criteria. The articles were rated by using a set of 11 basic methodologic standards for addressing diagnostic test research. None of the 11 studies met all of the criteria; only 5 studies met 5 or more criteria. All studies compared CT with either pulmonary angiography or another reference standard (high-probability V/Q scan plus high clinical suspicion) to confirm the diagnosis of PE. The studies were not methodologically similar enough to perform a meta-analysis.

OUTCOMES MEASURED: The primary outcome was the presence of a PE.

RESULTS: Compared with the gold standard of pulmonary angiography, the sensitivity of spiral CT ranged from 64% to 93%. If a PE is present, the probability of a positive CT scan is 64% to 93%. That means up to one third of PEs could be missed. The reported specificity ranged from 89% to 100%, which corresponds to a false-positive rate of 0% to 11%. These results are similar to those of another recent systematic review in which the authors reported a sensitivity range of 53% to 100% and a specificity range of 81% to 100%.¹ Nine of the studies differentiated between large central and small subsegmental vessel embolism. When stratified by site, the sensitivity for spiral CT was much higher for central vessel PE (83% to 100%) than for subsegmental vessel PE (29%).