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Non-Invasive Blood and Stool CRC Screening Tests: Available Modalities and Their Clinical Application
Introduction
Colorectal cancer (CRC) screening significantly reduces CRC incidence and mortality, but only 65% of eligible individuals report being up-to-date with screening.1 Colonoscopy is the most widely used opportunistic screening method in the United States and is associated with many barriers to uptake. Providing patients a choice of colonoscopy and/or stool-based tests, improves screening adherence in randomized controlled trials.2,3 Non-invasive screening options have expanded from stool occult blood and multi-target DNA tests, to multi-target stool RNA tests, and novel blood-based tests, the latter only U.S. Food and Drug Administration (FDA) approved for patients who refuse colonoscopy and stool-based tests.
Stool Occult Blood Tests
Guaiac-based fecal occult blood testing (gFOBT) significantly reduces CRC mortality by 33%-35% when implemented on an annual or biennial basis.4,5 Fecal immunochemical testing (FIT) has supplanted gFOBT with advantages including independence from dietary restriction and medication-related interference, use of antibodies specific to human globin, and the need for only a single stool sample.
The most common threshold for a positive FIT in the U.S. is ≥ 20 micrograms (μg) of hemoglobin per gram (g) of stool. FIT is approved by the FDA as a qualitative positive or negative result based on a threshold value.6 A meta-analysis summarized test characteristics of commercially available FITs at various detection thresholds.7 The CRC sensitivity and specificity was 75% and 95% for ≥ 20 ug hemoglobin/g stool, and 91% and 90% for 10 ug hemoglobin/g stool, respectively. The sensitivity for advanced adenomas ranged from 25% at 20 μg/g to 40% at a 10 μg/g. Programmatic use of FIT in adults ages ≥ 50 years at 20 ug/g of stool, in cohort and case control studies, has been shown to significantly reduce CRC mortality by 33%-40% and advanced stage CRC by 34%.8,9
Over 57,000 average-risk individuals ages 50–69 years were randomized to biennial FIT or one-time colonoscopy and followed for 10 years.10 CRC mortality and incidence was similar between the groups: 0.22% with FIT vs. 0.24% with colonoscopy and 1.13% with FIT vs. 1.22% with colonoscopy, respectively. Thus, confirming biennial FIT screening is non-inferior to one-time colonoscopy in important CRC-related outcomes.
Multi-Target Stool Tests
Two multitarget stool DNA tests (mt-sDNA) known as Cologuard™ and Cologuard Plus™ have been approved by the FDA. Both tests include a FIT (with a positivity threshold of 20 μg hemoglobin per gram of stool) combined with DNA methylation markers. The test result is qualitative, reported as a positive or negative. Cologuard™ markers include methylated BMP3, NDRG4, and mutant KRAS while Cologuard Plus™ assesses methylated LASS4, LRRC4, and PPP2R5C. The respective mt-sDNA tests were studied in 9989 of 12,776 and 20,176 of 26,758 average-risk individuals undergoing colonoscopy and the results were compared to a commercially available FIT (with a positivity threshold of 20 μg hemoglobin/gram of stool).11,12 In both trials, the sensitivity for CRC and advanced precancerous lesions was higher with the mt-sDNA tests compared to FIT but had a significantly lower specificity for advanced precancerous lesions versus FIT (see Table 1). An age-related decline in specificity was noted in both trials with mt-sDNA, a trend not observed with FIT. This reduction may be attributed to age-related DNA methylation.
Multi-Target Stool RNA Test
A multi-target stool RNA test (mt-sRNA) commercially available as ColoSense™ is FDA-approved. It combines FIT (at a positivity threshold of 20 μg hemoglobin/gram of stool) with RNA-based stool markers. The combined results of the RNA markers, FIT, and smoking status provide a qualitative single test result. In the trial, 8,920 adults aged ≥45 underwent the mt-sRNA test and FIT followed by colonoscopy (13). The mt-sRNA showed higher sensitivity for CRC than FIT (94.4% versus 77.8%) and advanced adenomas (45.9% versus 28.9%) but lower CRC specificity (84.7% vs 94.7%) (Table 1). Unlike mt-sDNA-based tests, mt-sRNA showed consistent performance across age groups, addressing concerns about age-related declines in specificity attributed to DNA methylation.
Blood-Based Tests
In 2014, the first blood-based (BBT) CRC screening test known as Epi proColon™ was FDA but not Centers for Medicare & Medicaid Services (CMS) approved for average-risk adults ≥50 years of age who are offered and refused other U.S Preventive Services Task Force (USPSTF) endorsed CRC screening tests. It is a qualitative test for detection of circulating methylated Septin 9 (mSeptin9). The accuracy of mSeptin9 to detect CRC was assessed in a subset of 7941 asymptomatic average risk adults undergoing screening colonoscopy.14 The sensitivity and specificity for CRC were 48% and 91.5%, respectively. The sensitivity for advanced adenomas was 11.2%. An increase in sensitivity to 63.9% and reduction in specificity to 88.4% for CRC was demonstrated in a sub-analysis of available samples where an additional (third) polymerase chain replicate was performed. Epi proColon™ is not currently reimbursed by Medicare and not endorsed in the latest USPSTF guidelines.
Technologic advancements have improved the detection of circulating tumor markers in the blood. The Shield™ BBT approved by the FDA in 2024 for average risk adults ≥ 45 years integrates three types of cfDNA data (epigenetic changes resulting in the aberrant methylation or fragmentation patterns, and genomic changes resulting in somatic mutations) into a positive or negative test result. In the trial, 22,877 average-risk, asymptomatic individuals ages 45–84 were enrolled and clinical validation was performed in 7,861 of the participants.15 The sensitivity for CRC was 83.1% which decreased to 55% for stage I tumors (see Table 1). CRC specificity was 89.6% and the sensitivity for advanced adenomas and large sessile serrated lesions was 13.2%.
Another BBT SimpleScreen™, which is not yet FDA-approved, analyzed circulating, cell-free DNA methylation patterns in 27,010 evaluable average-risk, asymptomatic adults ages 45–85 years undergoing screening colonoscopy.16 The sensitivity and specificity for CRC was 79.2% and 91.5%, respectively. Similar to Shield, the sensitivity for stage I CRC was low at 57.1%. The sensitivity for advanced precancerous lesions, a secondary endpoint, was 12.5% which did not meet the prespecified study criteria.
Effectiveness and Cost Effectiveness
Modeling studies have evaluated novel noninvasive CRC screening tests compared to FIT and colonoscopy.17-20 One compared a hypothetical BBT performed every 3 years that meets the minimum CMS threshold CRC sensitivity and specificity of 74% and 90%, respectively, to other established CRC screening tests beginning at age 45.17 Every 3-year BBT reduced CRC incidence and mortality by 40% and 52%, respectively compared to no screening. However, the reductions were much lower than yearly FIT (72% and 76%, respectively), every 10 year colonoscopy (79% and 81%, respectively), and triennial mt-sDNA (68% and 73%, respectively). The BBT resulted in fewer quality-adjusted life-years per person compared to the alternatives.
Additionally, FIT, colonoscopy, and mt-sDNA were less costly and more effective. Advanced precancerous lesion detection was a key measure for a test’s effectiveness. BBT characteristics would require a CRC sensitivity and specificity of >90% and 90%, respectively, and 80% sensitivity for advanced precancerous lesions at a cost of ≤$120–$140 to be cost-effective compared to FIT at comparable participation rates.
Another analysis simulated colorectal neoplasia progression and compared clinical effectiveness and cost between annual FIT, every 3 year stool mt-sRNA, every 3 year stool mt-sDNA tests, every 3 year stool Shield™; these outcomes were compared to colonoscopy every 10 years and no screening in adults ≥ age 45 over different adherence rates.19 At real-world adherence rates of 60%, colonoscopy prevented most CRC cases and associated deaths. FIT was the most cost-effective strategy at all adherence levels. Between the multi-target stool tests and Shield™, mt-sRNA was the most cost-effective. Compared to FIT, mt-sRNA reduced CRC cases and deaths by 1% and 14%.
The third study evaluated CRC incidence and mortality, quality-adjusted life-years and costs with annual FIT, colonoscopy every 10 years, mt- sDNA tests, mt-sRNA test, and BBTs.20 The latest mt-sDNA (Colguard plus™) and mt-sRNA achieved benefits approaching FIT but the Shield™ test was substantially less effective. The authors hypothesized that if 15% of the population substituted Shield™ for current effective CRC screening strategies, an increase in CRC deaths would occur and require 9-10% of the unscreened population to uptake screening with Shield to avert the increases in CRC deaths due to the substitution effect.
Clinical Implications
The effectiveness of non-invasive screening strategies depends on their diagnostic performance, adherence, and ensuring a timely colonoscopy after a positive test. Two claims-based studies found 47.9% and 49% of patients underwent follow-up colonoscopy within 6 months of an abnormal stool or BBT CRC screening test, respectively.21-22
Conclusions
Non-invasive stool mt-sDNA and mt-sRNA have higher effectiveness than the new BBTs. BBTs can lead to increased CRC mortality if substituted for the FDA and CMS-approved, USPSTF-endorsed, CRC screening modalities. If future BBTs increase their sensitivity for CRC (including early-stage CRC) and advanced precancerous lesions and decrease their cost, they may prove to have similar cost-effectiveness to stool-based tests. Currently, BBTs are not a substitute for colonoscopy or other stool tests and should be offered to patients who refuse other CRC screening modalities. A personalized, risk-adapted approach, paired with improved adherence and follow-up are essential to optimize the population-level impact of CRC screening and ensure equitable, effective cancer prevention.
Dr. Gupta is based at the Division of Gastroenterology and Hepatology, Department of Medicine, University of Maryland School of Medicine, Baltimore. Dr. Burke and Dr. Macaron are based at the Department of Gastroenterology, Hepatology, and Nutrition, Cleveland Clinic, Cleveland, Ohio. Dr. Gupta and Dr. Macaron declared no conflicts of interest in regard to this article. Dr. Burke declared research support from Emtora Biosciences. She is a current consultant for Lumabridge, and has been a consultant for Sebela and Almirall. She also disclosed support from Myriad, Genzyme, Ferring, Merck, Sharp and Dohme, Abbvie, Salix, and Natera.
References
1. Benavidez GA, Sedani AE, Felder TM, Asare M, Rogers CR. Rural-urban disparities and trends in cancer screening: an analysis of Behavioral Risk Factor Surveillance System data (2018-2022). JNCI Cancer Spectr. 2024 Nov 1;8(6):pkae113
2. Galoosian A, Dai H, Croymans D, et al. Population Health Colorectal Cancer Screening Strategies in Adults Aged 45 to 49 Years: A Randomized Clinical Trial. JAMA. 2025 Aug 4:e2512049. doi: 10.1001/jama.2025.12049. Epub ahead of print.
3. Pilonis ND, Bugajski M, Wieszczy P, et al. Participation in Competing Strategies for Colorectal Cancer Screening: A Randomized Health Services Study (PICCOLINO Study). Gastroenterology. 2021 Mar;160(4):1097-1105.
4. Shaukat A, Mongin SJ, Geisser MS, et al. Long-term mortality after screening for colorectal cancer. N Engl J Med. 2013;369(12):1106–1114.
5. Kronborg O, Fenger C, Olsen J, Jørgensen OD, Søndergaard O. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet. 1996 Nov 30;348(9040):1467-71. doi: 10.1016/S0140-6736(96)03430-7. PMID: 8942774.
6. Burke CA, Lieberman D, Feuerstein JD. AGA Clinical Practice Update on Approach to the Use of Noninvasive Colorectal Cancer Screening Options: Commentary. Gastroenterology. 2022 Mar;162(3):952-956. doi: 10.1053/j.gastro.2021.09.075. Epub 2022 Jan 28. PMID: 35094786.
7. Imperiale TF, Gruber RN Stump TE, et al. Performance characteristics of fecal immunochemical tests for colorectal cancer and advanced adenomatous polyps: a systematic review and meta-analysis. Ann Intern Med 2019; 170(5):319-329
8. Doubeni CA, Corley DA, Jensen CD, et al. Fecal Immunochemical Test Screening and Risk of Colorectal Cancer Death. JAMA Netw Open. 2024 Jul 1;7(7):e2423671. doi: 10.1001/jamanetworkopen.2024.23671.
9. Chiu HM, Jen GH, Wang YW, et al. Long-term effectiveness of faecal immunochemical test screening for proximal and distal colorectal cancers. Gut. 2021 Dec;70(12):2321-2329. doi: 10.1136/gutjnl-2020-322545. Epub 2021 Jan 25.
10. Castells A, Quintero E, Bujanda L, et al; COLONPREV study investigators. Effect of invitation to colonoscopy versus fecal immunochemical test screening on colorectal cancer mortality (COLONPREV): a pragmatic, randomised, controlled, non-inferiority trial. Lancet. 2025;405(10486):1231–1239
11. Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med. 2014;370(14):1287-1297
12. Imperiale TF, Porter K, Zella J, et al. Next-Generation Multitarget Stool DNA Test for Colorectal Cancer Screening. N Engl J Med. 2024 Mar 14;390(11):984-993
13. Barnell EK, Wurtzler EM, La Rocca J, et al. Multitarget Stool RNA Test for Colorectal Cancer Screening. JAMA. 2023 Nov 14;330(18):1760-1768.
14. Church TR, Wandell M, Lofton-Day C, et al. Prospective evaluation of methylated SEPT9 in plasma for detection of asymptomatic colorectal cancer. Gut 2014; 63:317–325.
15. Chung DC, Gray DM 2nd, Singh H, et al. A Cell-free DNA Blood-Based Test for Colorectal Cancer Screening. N Engl J Med. 2024 Mar 14;390(11):973-983.
16. Shaukat A, Burke CA, Chan AT, et al. Clinical Validation of a Circulating Tumor DNA-Based Blood Test to Screen for Colorectal Cancer. JAMA. 2025 Jul 1;334(1):56-63.
17. Ladabaum U, Mannalithara A, Weng Y, et al. Comparative Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening with Blood-Based Biomarkers (Liquid Biopsy) vs Fecal Tests or Colonoscopy. Gastroenterology. 2024 Jul;167(2):378-391.
18. van den Puttelaar R, Nascimento de Lima P, Knudsen AB, et al. Effectiveness and cost-effectiveness of colorectal cancer screening with a blood test that meets the Centers for Medicare & Medicaid Services coverage decision. Gastroenterology 2024;167:368–377.
19. Shaukat A, Levin TR, Liang PS. Cost-effectiveness of Novel Noninvasive Screening Tests for Colorectal Neoplasia. Clin Gastroenterol Hepatol. 2025 Jun 23:S1542-3565(25)00525-7. doi: 10.1016/j.cgh.2025.06.006. Epub ahead of print. PMID: 40562290.
20. Ladabaum U, Mannalithara A, Schoen RE, Dominitz JA, Lieberman D. Projected Impact and Cost-Effectiveness of Novel Molecular Blood-Based or Stool-Based Screening Tests for Colorectal Cancer. Ann Intern Med. 2024 Dec;177(12):1610-1620.
20. Ciemins EL, Mohl JT, Moreno CA, Colangelo F, Smith RA, Barton M. Development of a Follow-Up Measure to Ensure Complete Screening for Colorectal Cancer. JAMA Netw Open. 2024 Mar 4;7(3):e242693. doi: 10.1001/jamanetworkopen.2024.2693.
21. Zaki TA, Zhang NJ, Forbes SP, Raymond VM, Das AK, May FP. Colonoscopic Follow-up After Abnormal Blood-Based Colorectal Cancer Screening Results. Gastroenterology. 2025 Jul 21:S0016-5085(25)05775-0. doi: 10.1053/j.gastro.2025.07.019. Epub ahead of print. PMID: 40744392.
Introduction
Colorectal cancer (CRC) screening significantly reduces CRC incidence and mortality, but only 65% of eligible individuals report being up-to-date with screening.1 Colonoscopy is the most widely used opportunistic screening method in the United States and is associated with many barriers to uptake. Providing patients a choice of colonoscopy and/or stool-based tests, improves screening adherence in randomized controlled trials.2,3 Non-invasive screening options have expanded from stool occult blood and multi-target DNA tests, to multi-target stool RNA tests, and novel blood-based tests, the latter only U.S. Food and Drug Administration (FDA) approved for patients who refuse colonoscopy and stool-based tests.
Stool Occult Blood Tests
Guaiac-based fecal occult blood testing (gFOBT) significantly reduces CRC mortality by 33%-35% when implemented on an annual or biennial basis.4,5 Fecal immunochemical testing (FIT) has supplanted gFOBT with advantages including independence from dietary restriction and medication-related interference, use of antibodies specific to human globin, and the need for only a single stool sample.
The most common threshold for a positive FIT in the U.S. is ≥ 20 micrograms (μg) of hemoglobin per gram (g) of stool. FIT is approved by the FDA as a qualitative positive or negative result based on a threshold value.6 A meta-analysis summarized test characteristics of commercially available FITs at various detection thresholds.7 The CRC sensitivity and specificity was 75% and 95% for ≥ 20 ug hemoglobin/g stool, and 91% and 90% for 10 ug hemoglobin/g stool, respectively. The sensitivity for advanced adenomas ranged from 25% at 20 μg/g to 40% at a 10 μg/g. Programmatic use of FIT in adults ages ≥ 50 years at 20 ug/g of stool, in cohort and case control studies, has been shown to significantly reduce CRC mortality by 33%-40% and advanced stage CRC by 34%.8,9
Over 57,000 average-risk individuals ages 50–69 years were randomized to biennial FIT or one-time colonoscopy and followed for 10 years.10 CRC mortality and incidence was similar between the groups: 0.22% with FIT vs. 0.24% with colonoscopy and 1.13% with FIT vs. 1.22% with colonoscopy, respectively. Thus, confirming biennial FIT screening is non-inferior to one-time colonoscopy in important CRC-related outcomes.
Multi-Target Stool Tests
Two multitarget stool DNA tests (mt-sDNA) known as Cologuard™ and Cologuard Plus™ have been approved by the FDA. Both tests include a FIT (with a positivity threshold of 20 μg hemoglobin per gram of stool) combined with DNA methylation markers. The test result is qualitative, reported as a positive or negative. Cologuard™ markers include methylated BMP3, NDRG4, and mutant KRAS while Cologuard Plus™ assesses methylated LASS4, LRRC4, and PPP2R5C. The respective mt-sDNA tests were studied in 9989 of 12,776 and 20,176 of 26,758 average-risk individuals undergoing colonoscopy and the results were compared to a commercially available FIT (with a positivity threshold of 20 μg hemoglobin/gram of stool).11,12 In both trials, the sensitivity for CRC and advanced precancerous lesions was higher with the mt-sDNA tests compared to FIT but had a significantly lower specificity for advanced precancerous lesions versus FIT (see Table 1). An age-related decline in specificity was noted in both trials with mt-sDNA, a trend not observed with FIT. This reduction may be attributed to age-related DNA methylation.
Multi-Target Stool RNA Test
A multi-target stool RNA test (mt-sRNA) commercially available as ColoSense™ is FDA-approved. It combines FIT (at a positivity threshold of 20 μg hemoglobin/gram of stool) with RNA-based stool markers. The combined results of the RNA markers, FIT, and smoking status provide a qualitative single test result. In the trial, 8,920 adults aged ≥45 underwent the mt-sRNA test and FIT followed by colonoscopy (13). The mt-sRNA showed higher sensitivity for CRC than FIT (94.4% versus 77.8%) and advanced adenomas (45.9% versus 28.9%) but lower CRC specificity (84.7% vs 94.7%) (Table 1). Unlike mt-sDNA-based tests, mt-sRNA showed consistent performance across age groups, addressing concerns about age-related declines in specificity attributed to DNA methylation.
Blood-Based Tests
In 2014, the first blood-based (BBT) CRC screening test known as Epi proColon™ was FDA but not Centers for Medicare & Medicaid Services (CMS) approved for average-risk adults ≥50 years of age who are offered and refused other U.S Preventive Services Task Force (USPSTF) endorsed CRC screening tests. It is a qualitative test for detection of circulating methylated Septin 9 (mSeptin9). The accuracy of mSeptin9 to detect CRC was assessed in a subset of 7941 asymptomatic average risk adults undergoing screening colonoscopy.14 The sensitivity and specificity for CRC were 48% and 91.5%, respectively. The sensitivity for advanced adenomas was 11.2%. An increase in sensitivity to 63.9% and reduction in specificity to 88.4% for CRC was demonstrated in a sub-analysis of available samples where an additional (third) polymerase chain replicate was performed. Epi proColon™ is not currently reimbursed by Medicare and not endorsed in the latest USPSTF guidelines.
Technologic advancements have improved the detection of circulating tumor markers in the blood. The Shield™ BBT approved by the FDA in 2024 for average risk adults ≥ 45 years integrates three types of cfDNA data (epigenetic changes resulting in the aberrant methylation or fragmentation patterns, and genomic changes resulting in somatic mutations) into a positive or negative test result. In the trial, 22,877 average-risk, asymptomatic individuals ages 45–84 were enrolled and clinical validation was performed in 7,861 of the participants.15 The sensitivity for CRC was 83.1% which decreased to 55% for stage I tumors (see Table 1). CRC specificity was 89.6% and the sensitivity for advanced adenomas and large sessile serrated lesions was 13.2%.
Another BBT SimpleScreen™, which is not yet FDA-approved, analyzed circulating, cell-free DNA methylation patterns in 27,010 evaluable average-risk, asymptomatic adults ages 45–85 years undergoing screening colonoscopy.16 The sensitivity and specificity for CRC was 79.2% and 91.5%, respectively. Similar to Shield, the sensitivity for stage I CRC was low at 57.1%. The sensitivity for advanced precancerous lesions, a secondary endpoint, was 12.5% which did not meet the prespecified study criteria.
Effectiveness and Cost Effectiveness
Modeling studies have evaluated novel noninvasive CRC screening tests compared to FIT and colonoscopy.17-20 One compared a hypothetical BBT performed every 3 years that meets the minimum CMS threshold CRC sensitivity and specificity of 74% and 90%, respectively, to other established CRC screening tests beginning at age 45.17 Every 3-year BBT reduced CRC incidence and mortality by 40% and 52%, respectively compared to no screening. However, the reductions were much lower than yearly FIT (72% and 76%, respectively), every 10 year colonoscopy (79% and 81%, respectively), and triennial mt-sDNA (68% and 73%, respectively). The BBT resulted in fewer quality-adjusted life-years per person compared to the alternatives.
Additionally, FIT, colonoscopy, and mt-sDNA were less costly and more effective. Advanced precancerous lesion detection was a key measure for a test’s effectiveness. BBT characteristics would require a CRC sensitivity and specificity of >90% and 90%, respectively, and 80% sensitivity for advanced precancerous lesions at a cost of ≤$120–$140 to be cost-effective compared to FIT at comparable participation rates.
Another analysis simulated colorectal neoplasia progression and compared clinical effectiveness and cost between annual FIT, every 3 year stool mt-sRNA, every 3 year stool mt-sDNA tests, every 3 year stool Shield™; these outcomes were compared to colonoscopy every 10 years and no screening in adults ≥ age 45 over different adherence rates.19 At real-world adherence rates of 60%, colonoscopy prevented most CRC cases and associated deaths. FIT was the most cost-effective strategy at all adherence levels. Between the multi-target stool tests and Shield™, mt-sRNA was the most cost-effective. Compared to FIT, mt-sRNA reduced CRC cases and deaths by 1% and 14%.
The third study evaluated CRC incidence and mortality, quality-adjusted life-years and costs with annual FIT, colonoscopy every 10 years, mt- sDNA tests, mt-sRNA test, and BBTs.20 The latest mt-sDNA (Colguard plus™) and mt-sRNA achieved benefits approaching FIT but the Shield™ test was substantially less effective. The authors hypothesized that if 15% of the population substituted Shield™ for current effective CRC screening strategies, an increase in CRC deaths would occur and require 9-10% of the unscreened population to uptake screening with Shield to avert the increases in CRC deaths due to the substitution effect.
Clinical Implications
The effectiveness of non-invasive screening strategies depends on their diagnostic performance, adherence, and ensuring a timely colonoscopy after a positive test. Two claims-based studies found 47.9% and 49% of patients underwent follow-up colonoscopy within 6 months of an abnormal stool or BBT CRC screening test, respectively.21-22
Conclusions
Non-invasive stool mt-sDNA and mt-sRNA have higher effectiveness than the new BBTs. BBTs can lead to increased CRC mortality if substituted for the FDA and CMS-approved, USPSTF-endorsed, CRC screening modalities. If future BBTs increase their sensitivity for CRC (including early-stage CRC) and advanced precancerous lesions and decrease their cost, they may prove to have similar cost-effectiveness to stool-based tests. Currently, BBTs are not a substitute for colonoscopy or other stool tests and should be offered to patients who refuse other CRC screening modalities. A personalized, risk-adapted approach, paired with improved adherence and follow-up are essential to optimize the population-level impact of CRC screening and ensure equitable, effective cancer prevention.
Dr. Gupta is based at the Division of Gastroenterology and Hepatology, Department of Medicine, University of Maryland School of Medicine, Baltimore. Dr. Burke and Dr. Macaron are based at the Department of Gastroenterology, Hepatology, and Nutrition, Cleveland Clinic, Cleveland, Ohio. Dr. Gupta and Dr. Macaron declared no conflicts of interest in regard to this article. Dr. Burke declared research support from Emtora Biosciences. She is a current consultant for Lumabridge, and has been a consultant for Sebela and Almirall. She also disclosed support from Myriad, Genzyme, Ferring, Merck, Sharp and Dohme, Abbvie, Salix, and Natera.
References
1. Benavidez GA, Sedani AE, Felder TM, Asare M, Rogers CR. Rural-urban disparities and trends in cancer screening: an analysis of Behavioral Risk Factor Surveillance System data (2018-2022). JNCI Cancer Spectr. 2024 Nov 1;8(6):pkae113
2. Galoosian A, Dai H, Croymans D, et al. Population Health Colorectal Cancer Screening Strategies in Adults Aged 45 to 49 Years: A Randomized Clinical Trial. JAMA. 2025 Aug 4:e2512049. doi: 10.1001/jama.2025.12049. Epub ahead of print.
3. Pilonis ND, Bugajski M, Wieszczy P, et al. Participation in Competing Strategies for Colorectal Cancer Screening: A Randomized Health Services Study (PICCOLINO Study). Gastroenterology. 2021 Mar;160(4):1097-1105.
4. Shaukat A, Mongin SJ, Geisser MS, et al. Long-term mortality after screening for colorectal cancer. N Engl J Med. 2013;369(12):1106–1114.
5. Kronborg O, Fenger C, Olsen J, Jørgensen OD, Søndergaard O. Randomised study of screening for colorectal cancer with faecal-occult-blood test. Lancet. 1996 Nov 30;348(9040):1467-71. doi: 10.1016/S0140-6736(96)03430-7. PMID: 8942774.
6. Burke CA, Lieberman D, Feuerstein JD. AGA Clinical Practice Update on Approach to the Use of Noninvasive Colorectal Cancer Screening Options: Commentary. Gastroenterology. 2022 Mar;162(3):952-956. doi: 10.1053/j.gastro.2021.09.075. Epub 2022 Jan 28. PMID: 35094786.
7. Imperiale TF, Gruber RN Stump TE, et al. Performance characteristics of fecal immunochemical tests for colorectal cancer and advanced adenomatous polyps: a systematic review and meta-analysis. Ann Intern Med 2019; 170(5):319-329
8. Doubeni CA, Corley DA, Jensen CD, et al. Fecal Immunochemical Test Screening and Risk of Colorectal Cancer Death. JAMA Netw Open. 2024 Jul 1;7(7):e2423671. doi: 10.1001/jamanetworkopen.2024.23671.
9. Chiu HM, Jen GH, Wang YW, et al. Long-term effectiveness of faecal immunochemical test screening for proximal and distal colorectal cancers. Gut. 2021 Dec;70(12):2321-2329. doi: 10.1136/gutjnl-2020-322545. Epub 2021 Jan 25.
10. Castells A, Quintero E, Bujanda L, et al; COLONPREV study investigators. Effect of invitation to colonoscopy versus fecal immunochemical test screening on colorectal cancer mortality (COLONPREV): a pragmatic, randomised, controlled, non-inferiority trial. Lancet. 2025;405(10486):1231–1239
11. Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med. 2014;370(14):1287-1297
12. Imperiale TF, Porter K, Zella J, et al. Next-Generation Multitarget Stool DNA Test for Colorectal Cancer Screening. N Engl J Med. 2024 Mar 14;390(11):984-993
13. Barnell EK, Wurtzler EM, La Rocca J, et al. Multitarget Stool RNA Test for Colorectal Cancer Screening. JAMA. 2023 Nov 14;330(18):1760-1768.
14. Church TR, Wandell M, Lofton-Day C, et al. Prospective evaluation of methylated SEPT9 in plasma for detection of asymptomatic colorectal cancer. Gut 2014; 63:317–325.
15. Chung DC, Gray DM 2nd, Singh H, et al. A Cell-free DNA Blood-Based Test for Colorectal Cancer Screening. N Engl J Med. 2024 Mar 14;390(11):973-983.
16. Shaukat A, Burke CA, Chan AT, et al. Clinical Validation of a Circulating Tumor DNA-Based Blood Test to Screen for Colorectal Cancer. JAMA. 2025 Jul 1;334(1):56-63.
17. Ladabaum U, Mannalithara A, Weng Y, et al. Comparative Effectiveness and Cost-Effectiveness of Colorectal Cancer Screening with Blood-Based Biomarkers (Liquid Biopsy) vs Fecal Tests or Colonoscopy. Gastroenterology. 2024 Jul;167(2):378-391.
18. van den Puttelaar R, Nascimento de Lima P, Knudsen AB, et al. Effectiveness and cost-effectiveness of colorectal cancer screening with a blood test that meets the Centers for Medicare & Medicaid Services coverage decision. Gastroenterology 2024;167:368–377.
19. Shaukat A, Levin TR, Liang PS. Cost-effectiveness of Novel Noninvasive Screening Tests for Colorectal Neoplasia. Clin Gastroenterol Hepatol. 2025 Jun 23:S1542-3565(25)00525-7. doi: 10.1016/j.cgh.2025.06.006. Epub ahead of print. PMID: 40562290.
20. Ladabaum U, Mannalithara A, Schoen RE, Dominitz JA, Lieberman D. Projected Impact and Cost-Effectiveness of Novel Molecular Blood-Based or Stool-Based Screening Tests for Colorectal Cancer. Ann Intern Med. 2024 Dec;177(12):1610-1620.
20. Ciemins EL, Mohl JT, Moreno CA, Colangelo F, Smith RA, Barton M. Development of a Follow-Up Measure to Ensure Complete Screening for Colorectal Cancer. JAMA Netw Open. 2024 Mar 4;7(3):e242693. doi: 10.1001/jamanetworkopen.2024.2693.
21. Zaki TA, Zhang NJ, Forbes SP, Raymond VM, Das AK, May FP. Colonoscopic Follow-up After Abnormal Blood-Based Colorectal Cancer Screening Results. Gastroenterology. 2025 Jul 21:S0016-5085(25)05775-0. doi: 10.1053/j.gastro.2025.07.019. Epub ahead of print. PMID: 40744392.
Introduction
Colorectal cancer (CRC) screening significantly reduces CRC incidence and mortality, but only 65% of eligible individuals report being up-to-date with screening.1 Colonoscopy is the most widely used opportunistic screening method in the United States and is associated with many barriers to uptake. Providing patients a choice of colonoscopy and/or stool-based tests, improves screening adherence in randomized controlled trials.2,3 Non-invasive screening options have expanded from stool occult blood and multi-target DNA tests, to multi-target stool RNA tests, and novel blood-based tests, the latter only U.S. Food and Drug Administration (FDA) approved for patients who refuse colonoscopy and stool-based tests.
Stool Occult Blood Tests
Guaiac-based fecal occult blood testing (gFOBT) significantly reduces CRC mortality by 33%-35% when implemented on an annual or biennial basis.4,5 Fecal immunochemical testing (FIT) has supplanted gFOBT with advantages including independence from dietary restriction and medication-related interference, use of antibodies specific to human globin, and the need for only a single stool sample.
The most common threshold for a positive FIT in the U.S. is ≥ 20 micrograms (μg) of hemoglobin per gram (g) of stool. FIT is approved by the FDA as a qualitative positive or negative result based on a threshold value.6 A meta-analysis summarized test characteristics of commercially available FITs at various detection thresholds.7 The CRC sensitivity and specificity was 75% and 95% for ≥ 20 ug hemoglobin/g stool, and 91% and 90% for 10 ug hemoglobin/g stool, respectively. The sensitivity for advanced adenomas ranged from 25% at 20 μg/g to 40% at a 10 μg/g. Programmatic use of FIT in adults ages ≥ 50 years at 20 ug/g of stool, in cohort and case control studies, has been shown to significantly reduce CRC mortality by 33%-40% and advanced stage CRC by 34%.8,9
Over 57,000 average-risk individuals ages 50–69 years were randomized to biennial FIT or one-time colonoscopy and followed for 10 years.10 CRC mortality and incidence was similar between the groups: 0.22% with FIT vs. 0.24% with colonoscopy and 1.13% with FIT vs. 1.22% with colonoscopy, respectively. Thus, confirming biennial FIT screening is non-inferior to one-time colonoscopy in important CRC-related outcomes.
Multi-Target Stool Tests
Two multitarget stool DNA tests (mt-sDNA) known as Cologuard™ and Cologuard Plus™ have been approved by the FDA. Both tests include a FIT (with a positivity threshold of 20 μg hemoglobin per gram of stool) combined with DNA methylation markers. The test result is qualitative, reported as a positive or negative. Cologuard™ markers include methylated BMP3, NDRG4, and mutant KRAS while Cologuard Plus™ assesses methylated LASS4, LRRC4, and PPP2R5C. The respective mt-sDNA tests were studied in 9989 of 12,776 and 20,176 of 26,758 average-risk individuals undergoing colonoscopy and the results were compared to a commercially available FIT (with a positivity threshold of 20 μg hemoglobin/gram of stool).11,12 In both trials, the sensitivity for CRC and advanced precancerous lesions was higher with the mt-sDNA tests compared to FIT but had a significantly lower specificity for advanced precancerous lesions versus FIT (see Table 1). An age-related decline in specificity was noted in both trials with mt-sDNA, a trend not observed with FIT. This reduction may be attributed to age-related DNA methylation.
Multi-Target Stool RNA Test
A multi-target stool RNA test (mt-sRNA) commercially available as ColoSense™ is FDA-approved. It combines FIT (at a positivity threshold of 20 μg hemoglobin/gram of stool) with RNA-based stool markers. The combined results of the RNA markers, FIT, and smoking status provide a qualitative single test result. In the trial, 8,920 adults aged ≥45 underwent the mt-sRNA test and FIT followed by colonoscopy (13). The mt-sRNA showed higher sensitivity for CRC than FIT (94.4% versus 77.8%) and advanced adenomas (45.9% versus 28.9%) but lower CRC specificity (84.7% vs 94.7%) (Table 1). Unlike mt-sDNA-based tests, mt-sRNA showed consistent performance across age groups, addressing concerns about age-related declines in specificity attributed to DNA methylation.
Blood-Based Tests
In 2014, the first blood-based (BBT) CRC screening test known as Epi proColon™ was FDA but not Centers for Medicare & Medicaid Services (CMS) approved for average-risk adults ≥50 years of age who are offered and refused other U.S Preventive Services Task Force (USPSTF) endorsed CRC screening tests. It is a qualitative test for detection of circulating methylated Septin 9 (mSeptin9). The accuracy of mSeptin9 to detect CRC was assessed in a subset of 7941 asymptomatic average risk adults undergoing screening colonoscopy.14 The sensitivity and specificity for CRC were 48% and 91.5%, respectively. The sensitivity for advanced adenomas was 11.2%. An increase in sensitivity to 63.9% and reduction in specificity to 88.4% for CRC was demonstrated in a sub-analysis of available samples where an additional (third) polymerase chain replicate was performed. Epi proColon™ is not currently reimbursed by Medicare and not endorsed in the latest USPSTF guidelines.
Technologic advancements have improved the detection of circulating tumor markers in the blood. The Shield™ BBT approved by the FDA in 2024 for average risk adults ≥ 45 years integrates three types of cfDNA data (epigenetic changes resulting in the aberrant methylation or fragmentation patterns, and genomic changes resulting in somatic mutations) into a positive or negative test result. In the trial, 22,877 average-risk, asymptomatic individuals ages 45–84 were enrolled and clinical validation was performed in 7,861 of the participants.15 The sensitivity for CRC was 83.1% which decreased to 55% for stage I tumors (see Table 1). CRC specificity was 89.6% and the sensitivity for advanced adenomas and large sessile serrated lesions was 13.2%.
Another BBT SimpleScreen™, which is not yet FDA-approved, analyzed circulating, cell-free DNA methylation patterns in 27,010 evaluable average-risk, asymptomatic adults ages 45–85 years undergoing screening colonoscopy.16 The sensitivity and specificity for CRC was 79.2% and 91.5%, respectively. Similar to Shield, the sensitivity for stage I CRC was low at 57.1%. The sensitivity for advanced precancerous lesions, a secondary endpoint, was 12.5% which did not meet the prespecified study criteria.
Effectiveness and Cost Effectiveness
Modeling studies have evaluated novel noninvasive CRC screening tests compared to FIT and colonoscopy.17-20 One compared a hypothetical BBT performed every 3 years that meets the minimum CMS threshold CRC sensitivity and specificity of 74% and 90%, respectively, to other established CRC screening tests beginning at age 45.17 Every 3-year BBT reduced CRC incidence and mortality by 40% and 52%, respectively compared to no screening. However, the reductions were much lower than yearly FIT (72% and 76%, respectively), every 10 year colonoscopy (79% and 81%, respectively), and triennial mt-sDNA (68% and 73%, respectively). The BBT resulted in fewer quality-adjusted life-years per person compared to the alternatives.
Additionally, FIT, colonoscopy, and mt-sDNA were less costly and more effective. Advanced precancerous lesion detection was a key measure for a test’s effectiveness. BBT characteristics would require a CRC sensitivity and specificity of >90% and 90%, respectively, and 80% sensitivity for advanced precancerous lesions at a cost of ≤$120–$140 to be cost-effective compared to FIT at comparable participation rates.
Another analysis simulated colorectal neoplasia progression and compared clinical effectiveness and cost between annual FIT, every 3 year stool mt-sRNA, every 3 year stool mt-sDNA tests, every 3 year stool Shield™; these outcomes were compared to colonoscopy every 10 years and no screening in adults ≥ age 45 over different adherence rates.19 At real-world adherence rates of 60%, colonoscopy prevented most CRC cases and associated deaths. FIT was the most cost-effective strategy at all adherence levels. Between the multi-target stool tests and Shield™, mt-sRNA was the most cost-effective. Compared to FIT, mt-sRNA reduced CRC cases and deaths by 1% and 14%.
The third study evaluated CRC incidence and mortality, quality-adjusted life-years and costs with annual FIT, colonoscopy every 10 years, mt- sDNA tests, mt-sRNA test, and BBTs.20 The latest mt-sDNA (Colguard plus™) and mt-sRNA achieved benefits approaching FIT but the Shield™ test was substantially less effective. The authors hypothesized that if 15% of the population substituted Shield™ for current effective CRC screening strategies, an increase in CRC deaths would occur and require 9-10% of the unscreened population to uptake screening with Shield to avert the increases in CRC deaths due to the substitution effect.
Clinical Implications
The effectiveness of non-invasive screening strategies depends on their diagnostic performance, adherence, and ensuring a timely colonoscopy after a positive test. Two claims-based studies found 47.9% and 49% of patients underwent follow-up colonoscopy within 6 months of an abnormal stool or BBT CRC screening test, respectively.21-22
Conclusions
Non-invasive stool mt-sDNA and mt-sRNA have higher effectiveness than the new BBTs. BBTs can lead to increased CRC mortality if substituted for the FDA and CMS-approved, USPSTF-endorsed, CRC screening modalities. If future BBTs increase their sensitivity for CRC (including early-stage CRC) and advanced precancerous lesions and decrease their cost, they may prove to have similar cost-effectiveness to stool-based tests. Currently, BBTs are not a substitute for colonoscopy or other stool tests and should be offered to patients who refuse other CRC screening modalities. A personalized, risk-adapted approach, paired with improved adherence and follow-up are essential to optimize the population-level impact of CRC screening and ensure equitable, effective cancer prevention.
Dr. Gupta is based at the Division of Gastroenterology and Hepatology, Department of Medicine, University of Maryland School of Medicine, Baltimore. Dr. Burke and Dr. Macaron are based at the Department of Gastroenterology, Hepatology, and Nutrition, Cleveland Clinic, Cleveland, Ohio. Dr. Gupta and Dr. Macaron declared no conflicts of interest in regard to this article. Dr. Burke declared research support from Emtora Biosciences. She is a current consultant for Lumabridge, and has been a consultant for Sebela and Almirall. She also disclosed support from Myriad, Genzyme, Ferring, Merck, Sharp and Dohme, Abbvie, Salix, and Natera.
References
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Recurrent abdominal pain after laparoscopic cholecystectomy
Four months after undergoing laparoscopic cholecystectomy for symptomatic gallstones, an otherwise healthy 26-year-old woman begins to have episodes of epigastric and back pain similar to what she experienced before the surgery. The surgery was without complications, and her classic biliary colic disappeared afterward. Histologic evaluation of the surgical specimen revealed chronic cholecystitis with multiple small, mixed gallstones.
Now she describes a burning pain in her epigastrium and mid to upper back, starting about 30 minutes after a meal and lasting up to 4 hours. Sometimes it awakens her at night. She avoids eating for fear of inducing the pain. She has occasional chills but no fever, nausea, vomiting, jaundice, or changes in urine or stool color.
Three years ago she was diagnosed with a gastric ulcer induced by taking a nonsteroidal anti-inflammatory drug (NSAID). The ulcer was treated with a proton pump inhibitor for 1 month. She says the ulcer pain was dull and aching, different from her current pain.
Upper endoscopy 4 months ago (ie, before her laparoscopic cholecystectomy) showed no evidence of esophagitis or peptic ulcer disease.
Apart from her gallbladder operation, she has had no other surgery. According to the surgeon’s notes, intraoperative cholangiography was not performed, and no macroscopic changes of acute cholecystitis or difficult biliary anatomy were noted.
The patient does not smoke, does not drink alcohol, is not currently taking any medications, including NSAIDs or over-the-counter medications, and has not taken any recently. Her mother also had symptomatic gallstones requiring cholecystectomy.
On physical examination, only fever
On examination, her temperature is 101.2°F (38.4°C), blood pressure 117/80 mm Hg, heart rate 82 beats per minute, and blood oxygen saturation 99% on room air. Her weight is 138 lb (62.6 kg), height 5 feet 6 inches (168 cm).
There is no jaundice or pallor. Her heart and lung examinations are normal.
No costovertebral angle or spinal tenderness can be elicited.
Her laboratory values are shown in Table 1.
POSTCHOLECYSTECTOMY SYNDROME
1. After cholecystectomy, preoperative symptoms recur in what percentage of patients?
- 10% to 40%
- 50%
- 60%
- 80%
Postcholecystectomy syndrome—the recurrence of symptoms similar to those before the procedure—occurs in 10% to 40% of patients. The time to the onset of symptoms can range from 2 days to up to 25 years.1–4 Women may be at higher risk, with symptoms recurring in 43% vs 28% in men.5
Postcholecystectomy syndrome can have a biliary or a nonbiliary cause. Biliary causes include strictures, retained calculi, dropped calculi, tumors, sphincter of Oddi dysfunction, and calculi in the cystic duct remnant. Nonbiliary causes include functional and organic disorders such as peptic ulcer disease, gastroesophageal reflux, pancreatic disease, hepatocellular disorders, coronary artery disease, irritable bowel syndrome, and intercostal neuritis.
WHAT IS THE NEXT STEP?
2. Which is the most appropriate next step in the workup of this patient?
- Ultrasonography of the right upper quadrant
- Magnetic resonance cholangiopancreatography (MRCP)
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Observation and reassurance
- Review the operative record and consult with the surgeon
Although the patient is presenting with pain and fever, two features of the classic Charcot triad (pain, fever, jaundice) seen in cholangitis (infection of a bile duct), and although cholangitis almost confirms the diagnosis of common bile duct stones in a patient with gallstones (before or after cholecystectomy), other diagnoses to consider are bile duct injury, bile leak, and biloma.
Biloma can be detected with ultrasonography. Bile duct injuries are identified intraoperatively in up to 25% of patients. For those with an unrecognized injury, the clinical presentation is variable and depends on the type of injury. If a bile leak is present, patients present early, at a median of 3 days postoperatively. However, our patient presented with symptoms 4 months after her surgery. Patients with bile duct strictures without bile leak have a longer symptom-free interval and usually present with signs of biliary obstruction. Ultrasonography can then detect biliary dilatation.6
It would be very helpful to review the operative record and to talk to the surgeon to confirm that intraoperative cholangiography had not been done and to determine the level of difficulty of the surgery. (Intraoperative cholangiography involves the introduction of contrast dye into the biliary system by cannulation of the cystic duct or by direct injection into the common bile duct. An intraoperative cholangiogram is considered normal if the entire intrahepatic and extrahepatic biliary tree is seen to be filled with contrast.) A normal cholangiogram has a negative predictive value of 99.8% for the detection of ductal stones. Thus, a normal intraoperative cholangiogram can prevent unnecessary postoperative ECRP, since it almost always indicates a clean bile duct.7
Ultrasonography of the right upper quadrant has a low sensitivity (< 50%) for detecting common bile duct stones. However, it is highly operator-dependent, and it may be twice as sensitive if done by expert radiologists than by less experienced ones. Its limitations include poor visualization of the distal portion of the duct and low sensitivity in patients in whom the common bile duct is minimally dilated and also in patients with small stones. In most studies, however, it had a very high specificity—ie, greater than 95%.8
MRCP has a sensitivity of 82.6% and a specificity of 97.5% in detecting stones in the common bile duct.9 Therefore, normal results on abdominal ultrasonography and MRCP do not completely rule out stones.
Although this patient has a high pretest probability of having common bile duct stones, ERCP should be done only after a thorough review of the previous operative procedure.
Observation and reassurance are not appropriate in a patient with cholangitis, such as this patient, because waiting increases the risk of septicemia.
The patient undergoes ERCP with stone removal
Review of the operative report and discussion with the surgeon confirm that the laparoscopic procedure was uneventful and that intraoperative cholangiography was not done.
Therefore, the patient undergoes ERCP. The major papilla is normal. Cholangiography reveals nondilated common bile and intrahepatic ducts, with faint filling defects in the mid to distal common bile duct. Endoscopic sphincterotomy is performed, and three small stones are extracted from the common bile duct. Repeat balloon-occlusion cholangiography is normal.
The patient tolerates the procedure well and resumes a normal diet and normal activities.
Her pain persists, prompting an emergency room visit
Five days after her ERCP procedure, however, the same burning epigastric pain returns. As before, the pain occurs after eating and does not occur with fasting. At this time, she has no fever or chills.
WHAT IS CAUSING HER PAIN?
3. Which is the most likely cause of her persistent pain?
- Acute pancreatitis after ERCP
- Peptic ulcer disease
- Sphincter of Oddi dysfunction
- Biliary stones
The most likely cause is persistent biliary stones. The common bile duct was recently explored and stones were removed, but she may still have stones in the intrahepatic ducts or in the cystic duct remnant, both of which were unopacified during the ERCP procedure, indicating that either the test was incomplete or a stone is obstructing the passage of contrast. Her persistent symptoms warrant repeating her liver function tests.
Acute pancreatitis is the most common and feared complication of ERCP, and it should be suspected in any patient who develops abdominal pain within 6 hours of the procedure. It is much less likely to develop after 12 hours, however. Risk factors for post-ERCP pancreatitis include patient factors (young age, female sex, history of recurrent pancreatitis), procedural factors (difficult cannulation, minor papilla sphincterotomy), and, less likely, operator-related factors.10–13 In general, the more likely a patient is to have an abnormal and irregular common bile duct or pancreatic duct, the lower the risk of post-ERCP pancreatitis. The importance of operator-dependent factors is not yet clear.10–13
Despite the postprandial pattern of our patient’s pain and her history of gastric ulcer, peptic ulcer disease is unlikely in view of a normal esophagogastroduodenoscopic examination done 4 months earlier, and since she has no recent exposure to NSAIDs.
Sphincter of Oddi dysfunction may explain her symptoms, but she recently underwent endoscopic sphincterotomy, which is regarded as the most definitive treatment.14
WHAT SHOULD BE DONE NEXT?
4. What would be the best next step in her management?
- Repeat ERCP
- MRCP
- Endoscopic ultrasonography
- Observation and reassurance
MRCP is the most appropriate next step, given her recurrent symptoms. Repeat ERCP is not appropriate, since there is no evidence of cholangitis, and since her liver function tests had completely normalized.
A recent systematic review of endoscopic ultrasonography and MRCP for diagnosing choledocholithiasis found both tests to be highly accurate, with no statistically significant differences in sensitivity or specificity between the two.15 However, MRCP has the advantage of being noninvasive and of being able to show intrahepatic stones.
Park et al,16 in a prospective study of 66 patients with primary intrahepatic stones, concluded that MRCP findings were comparable to those of percutaneous transhepatic cholangioscopy, the reference standard for locating intrahepatic stones. The sensitivity, specificity, and accuracy of MRCP for detecting and locating intrahepatic stones were high (97%, 99%, and 98%, respectively).16 However, after sphincterotomy, pneumobilia may create an appearance that can be mistaken for intraductal stones.
She undergoes MRCP
The patient continues to have pain, and she has lost 5 pounds because she is still avoiding eating. At this point, she is beginning to wonder if her symptoms are psychogenic, since all the test results have been normal.
ERCP, MRCP, ULTRASONOGRAPHY?
5. What would be the best next step?
- Reassurance
- Referral to a psychiatrist
- Referral to a pain management clinic
- Endoscopic ultrasonography
- Repeat ERCP
Endoscopic ultrasonography is needed to look for cystic duct stones. Although several tests have shown normal results, the patient’s pain continues as in the previous episodes, making stone disease the most likely cause.
Although no stones were seen on MRCP and ultrasonography, a detailed evaluation for stones in a cystic duct or retained gallbladder remnant was not done satisfactorily.
Reassurance and referral to a psychiatrist or pain management clinic are not appropriate, since an organic cause of her pain has not been completely ruled out.
Findings on endoscopic ultrasonography
Endoscopic ultrasonography is performed and reveals a large (7-mm) stone in the area of the cystic duct remnant or gallbladder remnant (Figure 3). The common bile duct is normal.
CAUSES OF RETAINED GALLBLADDER AND CYSTIC DUCT REMNANT
6. What may have predisposed this patient to a retained gallbladder or cystic duct remnant after her surgery?
- Laparoscopic cholecystectomy
- Not doing intraoperative cholangiography
- Cholecystectomy for acute cholecystitis
- All of the above
All of the above may have contributed.
Postcholecystectomy syndrome can pose a diagnostic and therapeutic challenge, as in our patient. Although it has been reported since the advent of the operation, it is more common after laparoscopic cholecystectomy than after open surgery. One possible cause is stones in a cystic duct remnant, ie, a stub longer than 1 cm.
During open cholecystectomy, the cystic duct is ligated and cut as close to the common bile duct as possible, leaving only a small remnant. In laparoscopic cholecystectomy, it is divided closer to the gallbladder to avoid iatrogenic injury to the common bile duct, leaving a longer remnant. A long cystic duct remnant can be prevented by accurately locating the junction of the gallbladder and the cystic duct during cholecystectomy and by routinely doing intraoperative cholangiography. The presence of stones in a cystic duct or retained gallbladder remnant is a rare cause of postcholecystectomy syndrome, and suspicion is required to make the diagnosis.17–19
We should note that stones may also lurk in the short cystic duct remnant left after open cholecystectomy. In fact, the first case of cystic duct remnant, the so-called reformed gallbladder containing stones, was described in 1912 by Flörcken.20
Intraoperative cholangiography was introduced in 1931 by Mirizzi,21 who recommended its routine use. Since the advent of laparoscopic cholecystectomy in 1988, the routine use of intraoperative cholangiography has been debated. Advocates point to its ability to detect unsuspected calculi and to delineate the biliary anatomy, thus reducing the risk of biliary duct injury.7,22–25 Those who argue against its routine use emphasize the low reported rates of unsuspected stones in the common bile duct (2% to 3%), a longer operative time, the additional cost, and false-positive results that may lead to unnecessary common bile duct exploration. Another argument against its routine use is that most small ductal stones pass spontaneously without significant sequelae.26–28 Surgeons who use intraoperative cholangiography only selectively use it in patients with unclear biliary anatomy and preoperative biochemical or radiologic evidence of choledocholithiasis.
Case continued: She undergoes repeat ERCP
IF STONES ARE DIFFICULT TO EXTRACT
7. If the cystic duct stone were not amenable to endoscopic extraction, what would be the best alternative?
- Extracorporeal shock-wave lithotripsy (ESWL)
- Endoscopic biliary laser lithotripsy
- Repeat laparoscopic cholecystectomy
- All of the above
All of the above are alternatives.
A symptomatic stone in a cystic duct remnant is uncommon and is mentioned in the literature only in case series and case reports.
ESWL is effective for treating bile duct calculi.29 In a cohort of 239 patients with bile duct stones treated by ESWL, Benninger et al30 concluded that endoscopy plus ESWL was a definitive treatment for all patients except one, who subsequently underwent cholecystectomy. Once fragmented, the stones are extracted endoscopically.
Another fragmentation technique that can be offered to patients with stones in the cystic duct that are difficult to extract is contact fragmentation with a holmium laser placed in a transpapillary position under visual guidance.17
Repeat cholecystectomy with removal of stones in the cystic duct remnant (and removal of retained gallbladder remnants and reduction of the cystic duct remnant) has good postoperative results.17,18,31,32
After incomplete cholecystectomy, the cystic duct remnant and the Calot (cystohepatic) triangle are surrounded by inflamed scar tissue, and this was thought to make laparoscopic reoperation difficult.33 However, with advances in surgical technique and increasing experience of surgeons, repeat cholecystectomy can be done laparoscopically. It has now been suggested that laparoscopic exploration to remove the gallbladder remnants is safe and feasible in such patients.34,35
Discharge and follow-up
The patient is discharged home after the procedure. She is still free of symptoms 31 months later.
LESSONS LEARNED
Remnant cystic duct stones are uncommon
The estimated incidence of a retained calculus within the cystic duct remnant after cholecystectomy is less than 2.5%.2,36 In a series of 322 patients who underwent repeat surgery because of postcholecystectomy syndrome, Rogy et al36 found only 8 who had a stone in the cystic duct or gallbladder remnant, and in a series of 371 patients, Zhou el al2 found 4 who had a stone in the cystic duct remnant.
Stones in the cystic duct remnant are difficult to diagnose
Diagnosing stones in surgical remnants of the cystic duct or gallbladder can be difficult. The sensitivity of abdominal ultrasonography in detecting cystic duct stones is low—only 27% in one study, with a specificity of 100% and an accuracy of 75%.37 Ultrasonography may occasionally suggest cystic duct stones by showing an acoustic shadow in the anatomic region of the cystic duct. However, the results should be interpreted with caution.
Determining the accuracy of ERCP and MRCP in detecting cystic duct remnant stones is also difficult, as few cases have been reported and data may be conflicting. In a review of seven patients confirmed to have retained stones in a surgical remnant, Walsh et al17 found that ERCP correctly diagnosed the retained stone in only four out of six patients; MRCP was done in one patient, and it was read as normal.
In three cases of stones in a postsurgical gallbladder remnant, Hassan and Vilmann38 reported that ERCP and MRCP failed to identify the gallbladder remnant in two out of three cases, likely because the remaining structures are small. The diagnosis was finally made by endoscopic ultrasonography, which the authors concluded was a valuable method to visualize a small gallbladder remnant with stones.
Greater suspicion is needed in patients with typical biliary colic after cholecystectomy
Retained gallbladder remnant is described in the literature as a latent complication. The main problem is not the remnant itself but the chance that it harbors retained stones, which can lead to dilatation and inflammation of the remnant.
The patient can develop symptoms of acute cholecystitis or even acute cholangitis if the stone migrates to the common bile duct. Symptoms can develop as early as 2 weeks or as late as 25 years after laparoscopic cholecystectomy.
Endoscopic ultrasonography may be the best way to look for these remnant stones and to evaluate the bile duct and pancreas. Therefore, it should be part of the diagnostic algorithm in the evaluation of postcholecystectomy pain.
Mixed results with ERCP for extracting cystic duct stones
In case reports of cystic duct calculi after cholecystectomy, ERCP by itself has had mixed results. This traditional means of removing stones may succeed, as in our case. However, the success rate depends largely on anatomic factors such as the position of the stone in the cystic duct, the degree of stone impaction, the diameter of the cystic duct, and the number of valves in the duct.17
Stones in the cystic duct that cannot be extracted with ERCP may benefit from fragmentation techniques in situ via holmium laser followed by endoscopic extraction.
Repeat cholecystectomy is generally advised for any residual gallbladder, and it can be done laparoscopically.
- Lehman GA, Sherman S. Sphincter of Oddi dysfunction (postcholecystectomy syndrome). In:Yamada T, editor. Textbook of Gastroenterology. 2nd ed. Philadelphia: Lippincott; 1995:2251–2262.
- Zhou PH, Liu FL, Yao LQ, Qin XY. Endoscopic diagnosis and treatment of post-cholecystectomy syndrome. Hepatobiliary Pancreat Dis Int 2003; 2:117–120.
- Mergener K, Clavien PA, Branch MS, Baillie J. A stone in a grossly dilated cystic duct stump: a rare cause of postcholecystectomy pain. Am J Gastroenterol 1999; 94:229–231.
- Goenka MK, Kochhar R, Nagi B, Bhasin DK, Chowdhury A, Singh K. Endoscopic retrograde cholangiopancreatography in postcholecystectomy syndrome. J Assoc Physicians India 1996; 44:119–122.
- Bodvall B, Overgaard B. Cystic duct remnant after cholecystectomy: incidence studied by cholegraphy in 500 cases, and significance in 103 reoperations. Ann Surg 1966; 163:382–390.
- Bergman JJ, van den Brink GR, Rauws EA, et al. Treatment of bile duct lesions after laparoscopic cholecystectomy. Gut 1996; 38:141–147.
- Nickkholgh A, Soltaniyekta S, Kalbasi H. Routine versus selective intraoperative cholangiography during laparoscopic cholecystectomy: a survey of 2,130 patients undergoing laparoscopic cholecystectomy. Surg Endosc 2006; 20:868–874.
- Gandolfi L, Torresan F, Solmi L, Puccetti A. The role of ultrasound in biliary and pancreatic diseases. Eur J Ultrasound 2003; 16:141–159.
- Al Samaraee A, Khan U, Almashta Z, Yiannakou Y. Preoperative diagnosis of choledocholithiasis: the role of MRCP. Br J Hosp Med (Lond) 2009; 70:339–343.
- Freeman ML, DiSario JA, Nelson DB, et al. Risk factors for post-ERCP pancreatitis: a prospective, multicenter study. Gastrointest Endosc 2001; 54:425–434.
- Cheng CL, Sherman S, Watkins JL, et al. Risk factors for post-ERCP pancreatitis: a prospective multicenter study. Am J Gastroenterol 2006; 101:139–147.
- Mehta SN, Pavone E, Barkun JS, Bouchard S, Barkun AN. Predictors of post-ERCP complications in patients with suspected choledocholithiasis. Endoscopy 1998; 30:457–463.
- Badalov N, Tenner S, Baillie J. The prevention, recognition and treatment of post-ERCP pancreatitis. JOP 2009; 10:88–97.
- Geenen JE, Hogan WJ, Dodds WJ, Toouli J, Venu RP. The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction. N Engl J Med 1989; 320:82–87.
- Verma D, Kapadia A, Eisen GM, Adler DG. EUS vs MRCP for detection of choledocholithiasis. Gastrointest Endosc 2006; 64:248–254.
- Park DH, Kim MH, Lee SS, et al. Accuracy of magnetic resonance cholangiopancreatography for locating hepatolithiasis and detecting accompanying biliary strictures. Endoscopy 2004; 36:987–992.
- Walsh RM, Ponsky JL, Dumot J. Retained gallbladder/cystic duct remnant calculi as a cause of postcholecystectomy pain. Surg Endosc 2002; 16:981–984.
- Tantia O, Jain M, Khanna S, Sen B. Post cholecystectomy syndrome: role of cystic duct stump and re-intervention by laparoscopic surgery. J Minim Access Surg 2008; 4:71–75.
- Palanivelu C, Rangarajan M, Jategaonkar PA, Madankumar MV, Anand NV. Laparoscopic management of remnant cystic duct calculi: a retrospective study. Ann R Coll Surg Engl 2009; 91:25–29.
- Flörcken H. Gallenblasenregeneration mit Steinrecidiv nach Cholecystectomie. Deutsch Z Chir 1912; 113:604.
- Mirizzi PL. La colangiografía durante las operaciones de las vias biliares. Bol Soc Cirug Buenos Aires 1932; 16:1113.
- Soper NJ, Brunt LM. The case for routine operative cholangiography during laparoscopic cholecystectomy. Surg Clin North Am 1994; 74:953–959.
- Cuschieri A, Shimi S, Banting S, Nathanson LK, Pietrabissa A. Intraoperative cholangiography during laparoscopic cholecystectomy. Routine vs selective policy. Surg Endosc 1994; 8:302–305.
- Woods MS, Traverso LW, Kozarek RA, et al. Biliary tract complications of laparoscopic cholecystectomy are detected more frequently with routine intraoperative cholangiography. Surg Endosc 1995; 9:1076–1080.
- Vezakis A, Davides D, Ammori BJ, Martin IG, Larvin M, McMahon MJ. Intraoperative cholangiography during laparoscopic cholecystectomy. Surg Endosc 2000; 14:1118–1122.
- Ladocsi LT, Benitez LD, Filippone DR, Nance FC. Intraoperative cholangiography in laparoscopic cholecystectomy: a review of 734 consecutive cases. Am Surg 1997; 63:150–156.
- Clair DG, Brooks DC. Laparoscopic cholangiography. The case for a selective approach. Surg Clin North Am 1994; 74:961–966.
- Collins C, Maguire D, Ireland A, Fitzgerald E, O’Sullivan GC. A prospective study of common bile duct calculi in patients undergoing laparoscopic cholecystectomy: natural history of choledocholithiasis revisited. Ann Surg 2004; 239:28–33.
- Ponsky LE, Geisinger MA, Ponsky JL, Streem SB. Contemporary ‘urologic’ intervention in the pancreaticobiliary tree. Urology 2001; 57:21–25.
- Benninger J, Rabenstein T, Farnbacher M, Keppler J, Hahn EG, Schneider HT. Extracorporeal shockwave lithotripsy of gallstones in cystic duct remnants and Mirizzi syndrome. Gastrointest Endosc 2004; 60:454–459.
- Demetriades H, Pramateftakis MG, Kanellos I, Angelopoulos S, Mantzoros I, Betsis D. Retained gallbladder remnant after laparoscopic cholecystectomy. J Laparoendosc Adv Surg Tech A 2008; 18:276–279.
- Shaw C, O’Hanlon DM, Fenlon HM, McEntee GP. Cystic duct remnant and the ‘post-cholecystectomy syndrome. ’ Hepatogastroenterology 2004; 51:36–38.
- Rozsos I, Magyaródi Z, Orbán P. Cystic duct syndrome and minimally invasive surgery. [Hungarian] Orv Hetil 1997; 138:2397–2401.
- Chowbey PK, Bandyopadhyay SK, Sharma A, Khullar R, Soni V, Baijal M. Laparoscopic reintervention for residual gallstone disease. Surg Laparosc Endosc Percutan Tech 2003; 13:31–35.
- Clemente G, Giuliante F, Cadeddu F, Nuzzo G. Laparoscopic removal of gallbladder remnant and long cystic stump. Endoscopy 2001; 33:814–815.
- Rogy MA, Függer R, Herbst F, Schulz F. Reoperation after cholecystectomy. The role of the cystic duct stump. HPB Surg 1991; 4:129–134.
- Laing FC, Jeffrey RB. Choledocholithiasis and cystic duct obstruction: difficult ultrasonographic diagnosis. Radiology 1983; 146:475–479.
- Hassan H, Vilmann P. Insufficient cholecystectomy diagnosed by endoscopic ultrasonography. Endoscopy 2004; 36:236–238.
Four months after undergoing laparoscopic cholecystectomy for symptomatic gallstones, an otherwise healthy 26-year-old woman begins to have episodes of epigastric and back pain similar to what she experienced before the surgery. The surgery was without complications, and her classic biliary colic disappeared afterward. Histologic evaluation of the surgical specimen revealed chronic cholecystitis with multiple small, mixed gallstones.
Now she describes a burning pain in her epigastrium and mid to upper back, starting about 30 minutes after a meal and lasting up to 4 hours. Sometimes it awakens her at night. She avoids eating for fear of inducing the pain. She has occasional chills but no fever, nausea, vomiting, jaundice, or changes in urine or stool color.
Three years ago she was diagnosed with a gastric ulcer induced by taking a nonsteroidal anti-inflammatory drug (NSAID). The ulcer was treated with a proton pump inhibitor for 1 month. She says the ulcer pain was dull and aching, different from her current pain.
Upper endoscopy 4 months ago (ie, before her laparoscopic cholecystectomy) showed no evidence of esophagitis or peptic ulcer disease.
Apart from her gallbladder operation, she has had no other surgery. According to the surgeon’s notes, intraoperative cholangiography was not performed, and no macroscopic changes of acute cholecystitis or difficult biliary anatomy were noted.
The patient does not smoke, does not drink alcohol, is not currently taking any medications, including NSAIDs or over-the-counter medications, and has not taken any recently. Her mother also had symptomatic gallstones requiring cholecystectomy.
On physical examination, only fever
On examination, her temperature is 101.2°F (38.4°C), blood pressure 117/80 mm Hg, heart rate 82 beats per minute, and blood oxygen saturation 99% on room air. Her weight is 138 lb (62.6 kg), height 5 feet 6 inches (168 cm).
There is no jaundice or pallor. Her heart and lung examinations are normal.
No costovertebral angle or spinal tenderness can be elicited.
Her laboratory values are shown in Table 1.
POSTCHOLECYSTECTOMY SYNDROME
1. After cholecystectomy, preoperative symptoms recur in what percentage of patients?
- 10% to 40%
- 50%
- 60%
- 80%
Postcholecystectomy syndrome—the recurrence of symptoms similar to those before the procedure—occurs in 10% to 40% of patients. The time to the onset of symptoms can range from 2 days to up to 25 years.1–4 Women may be at higher risk, with symptoms recurring in 43% vs 28% in men.5
Postcholecystectomy syndrome can have a biliary or a nonbiliary cause. Biliary causes include strictures, retained calculi, dropped calculi, tumors, sphincter of Oddi dysfunction, and calculi in the cystic duct remnant. Nonbiliary causes include functional and organic disorders such as peptic ulcer disease, gastroesophageal reflux, pancreatic disease, hepatocellular disorders, coronary artery disease, irritable bowel syndrome, and intercostal neuritis.
WHAT IS THE NEXT STEP?
2. Which is the most appropriate next step in the workup of this patient?
- Ultrasonography of the right upper quadrant
- Magnetic resonance cholangiopancreatography (MRCP)
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Observation and reassurance
- Review the operative record and consult with the surgeon
Although the patient is presenting with pain and fever, two features of the classic Charcot triad (pain, fever, jaundice) seen in cholangitis (infection of a bile duct), and although cholangitis almost confirms the diagnosis of common bile duct stones in a patient with gallstones (before or after cholecystectomy), other diagnoses to consider are bile duct injury, bile leak, and biloma.
Biloma can be detected with ultrasonography. Bile duct injuries are identified intraoperatively in up to 25% of patients. For those with an unrecognized injury, the clinical presentation is variable and depends on the type of injury. If a bile leak is present, patients present early, at a median of 3 days postoperatively. However, our patient presented with symptoms 4 months after her surgery. Patients with bile duct strictures without bile leak have a longer symptom-free interval and usually present with signs of biliary obstruction. Ultrasonography can then detect biliary dilatation.6
It would be very helpful to review the operative record and to talk to the surgeon to confirm that intraoperative cholangiography had not been done and to determine the level of difficulty of the surgery. (Intraoperative cholangiography involves the introduction of contrast dye into the biliary system by cannulation of the cystic duct or by direct injection into the common bile duct. An intraoperative cholangiogram is considered normal if the entire intrahepatic and extrahepatic biliary tree is seen to be filled with contrast.) A normal cholangiogram has a negative predictive value of 99.8% for the detection of ductal stones. Thus, a normal intraoperative cholangiogram can prevent unnecessary postoperative ECRP, since it almost always indicates a clean bile duct.7
Ultrasonography of the right upper quadrant has a low sensitivity (< 50%) for detecting common bile duct stones. However, it is highly operator-dependent, and it may be twice as sensitive if done by expert radiologists than by less experienced ones. Its limitations include poor visualization of the distal portion of the duct and low sensitivity in patients in whom the common bile duct is minimally dilated and also in patients with small stones. In most studies, however, it had a very high specificity—ie, greater than 95%.8
MRCP has a sensitivity of 82.6% and a specificity of 97.5% in detecting stones in the common bile duct.9 Therefore, normal results on abdominal ultrasonography and MRCP do not completely rule out stones.
Although this patient has a high pretest probability of having common bile duct stones, ERCP should be done only after a thorough review of the previous operative procedure.
Observation and reassurance are not appropriate in a patient with cholangitis, such as this patient, because waiting increases the risk of septicemia.
The patient undergoes ERCP with stone removal
Review of the operative report and discussion with the surgeon confirm that the laparoscopic procedure was uneventful and that intraoperative cholangiography was not done.
Therefore, the patient undergoes ERCP. The major papilla is normal. Cholangiography reveals nondilated common bile and intrahepatic ducts, with faint filling defects in the mid to distal common bile duct. Endoscopic sphincterotomy is performed, and three small stones are extracted from the common bile duct. Repeat balloon-occlusion cholangiography is normal.
The patient tolerates the procedure well and resumes a normal diet and normal activities.
Her pain persists, prompting an emergency room visit
Five days after her ERCP procedure, however, the same burning epigastric pain returns. As before, the pain occurs after eating and does not occur with fasting. At this time, she has no fever or chills.
WHAT IS CAUSING HER PAIN?
3. Which is the most likely cause of her persistent pain?
- Acute pancreatitis after ERCP
- Peptic ulcer disease
- Sphincter of Oddi dysfunction
- Biliary stones
The most likely cause is persistent biliary stones. The common bile duct was recently explored and stones were removed, but she may still have stones in the intrahepatic ducts or in the cystic duct remnant, both of which were unopacified during the ERCP procedure, indicating that either the test was incomplete or a stone is obstructing the passage of contrast. Her persistent symptoms warrant repeating her liver function tests.
Acute pancreatitis is the most common and feared complication of ERCP, and it should be suspected in any patient who develops abdominal pain within 6 hours of the procedure. It is much less likely to develop after 12 hours, however. Risk factors for post-ERCP pancreatitis include patient factors (young age, female sex, history of recurrent pancreatitis), procedural factors (difficult cannulation, minor papilla sphincterotomy), and, less likely, operator-related factors.10–13 In general, the more likely a patient is to have an abnormal and irregular common bile duct or pancreatic duct, the lower the risk of post-ERCP pancreatitis. The importance of operator-dependent factors is not yet clear.10–13
Despite the postprandial pattern of our patient’s pain and her history of gastric ulcer, peptic ulcer disease is unlikely in view of a normal esophagogastroduodenoscopic examination done 4 months earlier, and since she has no recent exposure to NSAIDs.
Sphincter of Oddi dysfunction may explain her symptoms, but she recently underwent endoscopic sphincterotomy, which is regarded as the most definitive treatment.14
WHAT SHOULD BE DONE NEXT?
4. What would be the best next step in her management?
- Repeat ERCP
- MRCP
- Endoscopic ultrasonography
- Observation and reassurance
MRCP is the most appropriate next step, given her recurrent symptoms. Repeat ERCP is not appropriate, since there is no evidence of cholangitis, and since her liver function tests had completely normalized.
A recent systematic review of endoscopic ultrasonography and MRCP for diagnosing choledocholithiasis found both tests to be highly accurate, with no statistically significant differences in sensitivity or specificity between the two.15 However, MRCP has the advantage of being noninvasive and of being able to show intrahepatic stones.
Park et al,16 in a prospective study of 66 patients with primary intrahepatic stones, concluded that MRCP findings were comparable to those of percutaneous transhepatic cholangioscopy, the reference standard for locating intrahepatic stones. The sensitivity, specificity, and accuracy of MRCP for detecting and locating intrahepatic stones were high (97%, 99%, and 98%, respectively).16 However, after sphincterotomy, pneumobilia may create an appearance that can be mistaken for intraductal stones.
She undergoes MRCP
The patient continues to have pain, and she has lost 5 pounds because she is still avoiding eating. At this point, she is beginning to wonder if her symptoms are psychogenic, since all the test results have been normal.
ERCP, MRCP, ULTRASONOGRAPHY?
5. What would be the best next step?
- Reassurance
- Referral to a psychiatrist
- Referral to a pain management clinic
- Endoscopic ultrasonography
- Repeat ERCP
Endoscopic ultrasonography is needed to look for cystic duct stones. Although several tests have shown normal results, the patient’s pain continues as in the previous episodes, making stone disease the most likely cause.
Although no stones were seen on MRCP and ultrasonography, a detailed evaluation for stones in a cystic duct or retained gallbladder remnant was not done satisfactorily.
Reassurance and referral to a psychiatrist or pain management clinic are not appropriate, since an organic cause of her pain has not been completely ruled out.
Findings on endoscopic ultrasonography
Endoscopic ultrasonography is performed and reveals a large (7-mm) stone in the area of the cystic duct remnant or gallbladder remnant (Figure 3). The common bile duct is normal.
CAUSES OF RETAINED GALLBLADDER AND CYSTIC DUCT REMNANT
6. What may have predisposed this patient to a retained gallbladder or cystic duct remnant after her surgery?
- Laparoscopic cholecystectomy
- Not doing intraoperative cholangiography
- Cholecystectomy for acute cholecystitis
- All of the above
All of the above may have contributed.
Postcholecystectomy syndrome can pose a diagnostic and therapeutic challenge, as in our patient. Although it has been reported since the advent of the operation, it is more common after laparoscopic cholecystectomy than after open surgery. One possible cause is stones in a cystic duct remnant, ie, a stub longer than 1 cm.
During open cholecystectomy, the cystic duct is ligated and cut as close to the common bile duct as possible, leaving only a small remnant. In laparoscopic cholecystectomy, it is divided closer to the gallbladder to avoid iatrogenic injury to the common bile duct, leaving a longer remnant. A long cystic duct remnant can be prevented by accurately locating the junction of the gallbladder and the cystic duct during cholecystectomy and by routinely doing intraoperative cholangiography. The presence of stones in a cystic duct or retained gallbladder remnant is a rare cause of postcholecystectomy syndrome, and suspicion is required to make the diagnosis.17–19
We should note that stones may also lurk in the short cystic duct remnant left after open cholecystectomy. In fact, the first case of cystic duct remnant, the so-called reformed gallbladder containing stones, was described in 1912 by Flörcken.20
Intraoperative cholangiography was introduced in 1931 by Mirizzi,21 who recommended its routine use. Since the advent of laparoscopic cholecystectomy in 1988, the routine use of intraoperative cholangiography has been debated. Advocates point to its ability to detect unsuspected calculi and to delineate the biliary anatomy, thus reducing the risk of biliary duct injury.7,22–25 Those who argue against its routine use emphasize the low reported rates of unsuspected stones in the common bile duct (2% to 3%), a longer operative time, the additional cost, and false-positive results that may lead to unnecessary common bile duct exploration. Another argument against its routine use is that most small ductal stones pass spontaneously without significant sequelae.26–28 Surgeons who use intraoperative cholangiography only selectively use it in patients with unclear biliary anatomy and preoperative biochemical or radiologic evidence of choledocholithiasis.
Case continued: She undergoes repeat ERCP
IF STONES ARE DIFFICULT TO EXTRACT
7. If the cystic duct stone were not amenable to endoscopic extraction, what would be the best alternative?
- Extracorporeal shock-wave lithotripsy (ESWL)
- Endoscopic biliary laser lithotripsy
- Repeat laparoscopic cholecystectomy
- All of the above
All of the above are alternatives.
A symptomatic stone in a cystic duct remnant is uncommon and is mentioned in the literature only in case series and case reports.
ESWL is effective for treating bile duct calculi.29 In a cohort of 239 patients with bile duct stones treated by ESWL, Benninger et al30 concluded that endoscopy plus ESWL was a definitive treatment for all patients except one, who subsequently underwent cholecystectomy. Once fragmented, the stones are extracted endoscopically.
Another fragmentation technique that can be offered to patients with stones in the cystic duct that are difficult to extract is contact fragmentation with a holmium laser placed in a transpapillary position under visual guidance.17
Repeat cholecystectomy with removal of stones in the cystic duct remnant (and removal of retained gallbladder remnants and reduction of the cystic duct remnant) has good postoperative results.17,18,31,32
After incomplete cholecystectomy, the cystic duct remnant and the Calot (cystohepatic) triangle are surrounded by inflamed scar tissue, and this was thought to make laparoscopic reoperation difficult.33 However, with advances in surgical technique and increasing experience of surgeons, repeat cholecystectomy can be done laparoscopically. It has now been suggested that laparoscopic exploration to remove the gallbladder remnants is safe and feasible in such patients.34,35
Discharge and follow-up
The patient is discharged home after the procedure. She is still free of symptoms 31 months later.
LESSONS LEARNED
Remnant cystic duct stones are uncommon
The estimated incidence of a retained calculus within the cystic duct remnant after cholecystectomy is less than 2.5%.2,36 In a series of 322 patients who underwent repeat surgery because of postcholecystectomy syndrome, Rogy et al36 found only 8 who had a stone in the cystic duct or gallbladder remnant, and in a series of 371 patients, Zhou el al2 found 4 who had a stone in the cystic duct remnant.
Stones in the cystic duct remnant are difficult to diagnose
Diagnosing stones in surgical remnants of the cystic duct or gallbladder can be difficult. The sensitivity of abdominal ultrasonography in detecting cystic duct stones is low—only 27% in one study, with a specificity of 100% and an accuracy of 75%.37 Ultrasonography may occasionally suggest cystic duct stones by showing an acoustic shadow in the anatomic region of the cystic duct. However, the results should be interpreted with caution.
Determining the accuracy of ERCP and MRCP in detecting cystic duct remnant stones is also difficult, as few cases have been reported and data may be conflicting. In a review of seven patients confirmed to have retained stones in a surgical remnant, Walsh et al17 found that ERCP correctly diagnosed the retained stone in only four out of six patients; MRCP was done in one patient, and it was read as normal.
In three cases of stones in a postsurgical gallbladder remnant, Hassan and Vilmann38 reported that ERCP and MRCP failed to identify the gallbladder remnant in two out of three cases, likely because the remaining structures are small. The diagnosis was finally made by endoscopic ultrasonography, which the authors concluded was a valuable method to visualize a small gallbladder remnant with stones.
Greater suspicion is needed in patients with typical biliary colic after cholecystectomy
Retained gallbladder remnant is described in the literature as a latent complication. The main problem is not the remnant itself but the chance that it harbors retained stones, which can lead to dilatation and inflammation of the remnant.
The patient can develop symptoms of acute cholecystitis or even acute cholangitis if the stone migrates to the common bile duct. Symptoms can develop as early as 2 weeks or as late as 25 years after laparoscopic cholecystectomy.
Endoscopic ultrasonography may be the best way to look for these remnant stones and to evaluate the bile duct and pancreas. Therefore, it should be part of the diagnostic algorithm in the evaluation of postcholecystectomy pain.
Mixed results with ERCP for extracting cystic duct stones
In case reports of cystic duct calculi after cholecystectomy, ERCP by itself has had mixed results. This traditional means of removing stones may succeed, as in our case. However, the success rate depends largely on anatomic factors such as the position of the stone in the cystic duct, the degree of stone impaction, the diameter of the cystic duct, and the number of valves in the duct.17
Stones in the cystic duct that cannot be extracted with ERCP may benefit from fragmentation techniques in situ via holmium laser followed by endoscopic extraction.
Repeat cholecystectomy is generally advised for any residual gallbladder, and it can be done laparoscopically.
Four months after undergoing laparoscopic cholecystectomy for symptomatic gallstones, an otherwise healthy 26-year-old woman begins to have episodes of epigastric and back pain similar to what she experienced before the surgery. The surgery was without complications, and her classic biliary colic disappeared afterward. Histologic evaluation of the surgical specimen revealed chronic cholecystitis with multiple small, mixed gallstones.
Now she describes a burning pain in her epigastrium and mid to upper back, starting about 30 minutes after a meal and lasting up to 4 hours. Sometimes it awakens her at night. She avoids eating for fear of inducing the pain. She has occasional chills but no fever, nausea, vomiting, jaundice, or changes in urine or stool color.
Three years ago she was diagnosed with a gastric ulcer induced by taking a nonsteroidal anti-inflammatory drug (NSAID). The ulcer was treated with a proton pump inhibitor for 1 month. She says the ulcer pain was dull and aching, different from her current pain.
Upper endoscopy 4 months ago (ie, before her laparoscopic cholecystectomy) showed no evidence of esophagitis or peptic ulcer disease.
Apart from her gallbladder operation, she has had no other surgery. According to the surgeon’s notes, intraoperative cholangiography was not performed, and no macroscopic changes of acute cholecystitis or difficult biliary anatomy were noted.
The patient does not smoke, does not drink alcohol, is not currently taking any medications, including NSAIDs or over-the-counter medications, and has not taken any recently. Her mother also had symptomatic gallstones requiring cholecystectomy.
On physical examination, only fever
On examination, her temperature is 101.2°F (38.4°C), blood pressure 117/80 mm Hg, heart rate 82 beats per minute, and blood oxygen saturation 99% on room air. Her weight is 138 lb (62.6 kg), height 5 feet 6 inches (168 cm).
There is no jaundice or pallor. Her heart and lung examinations are normal.
No costovertebral angle or spinal tenderness can be elicited.
Her laboratory values are shown in Table 1.
POSTCHOLECYSTECTOMY SYNDROME
1. After cholecystectomy, preoperative symptoms recur in what percentage of patients?
- 10% to 40%
- 50%
- 60%
- 80%
Postcholecystectomy syndrome—the recurrence of symptoms similar to those before the procedure—occurs in 10% to 40% of patients. The time to the onset of symptoms can range from 2 days to up to 25 years.1–4 Women may be at higher risk, with symptoms recurring in 43% vs 28% in men.5
Postcholecystectomy syndrome can have a biliary or a nonbiliary cause. Biliary causes include strictures, retained calculi, dropped calculi, tumors, sphincter of Oddi dysfunction, and calculi in the cystic duct remnant. Nonbiliary causes include functional and organic disorders such as peptic ulcer disease, gastroesophageal reflux, pancreatic disease, hepatocellular disorders, coronary artery disease, irritable bowel syndrome, and intercostal neuritis.
WHAT IS THE NEXT STEP?
2. Which is the most appropriate next step in the workup of this patient?
- Ultrasonography of the right upper quadrant
- Magnetic resonance cholangiopancreatography (MRCP)
- Endoscopic retrograde cholangiopancreatography (ERCP)
- Observation and reassurance
- Review the operative record and consult with the surgeon
Although the patient is presenting with pain and fever, two features of the classic Charcot triad (pain, fever, jaundice) seen in cholangitis (infection of a bile duct), and although cholangitis almost confirms the diagnosis of common bile duct stones in a patient with gallstones (before or after cholecystectomy), other diagnoses to consider are bile duct injury, bile leak, and biloma.
Biloma can be detected with ultrasonography. Bile duct injuries are identified intraoperatively in up to 25% of patients. For those with an unrecognized injury, the clinical presentation is variable and depends on the type of injury. If a bile leak is present, patients present early, at a median of 3 days postoperatively. However, our patient presented with symptoms 4 months after her surgery. Patients with bile duct strictures without bile leak have a longer symptom-free interval and usually present with signs of biliary obstruction. Ultrasonography can then detect biliary dilatation.6
It would be very helpful to review the operative record and to talk to the surgeon to confirm that intraoperative cholangiography had not been done and to determine the level of difficulty of the surgery. (Intraoperative cholangiography involves the introduction of contrast dye into the biliary system by cannulation of the cystic duct or by direct injection into the common bile duct. An intraoperative cholangiogram is considered normal if the entire intrahepatic and extrahepatic biliary tree is seen to be filled with contrast.) A normal cholangiogram has a negative predictive value of 99.8% for the detection of ductal stones. Thus, a normal intraoperative cholangiogram can prevent unnecessary postoperative ECRP, since it almost always indicates a clean bile duct.7
Ultrasonography of the right upper quadrant has a low sensitivity (< 50%) for detecting common bile duct stones. However, it is highly operator-dependent, and it may be twice as sensitive if done by expert radiologists than by less experienced ones. Its limitations include poor visualization of the distal portion of the duct and low sensitivity in patients in whom the common bile duct is minimally dilated and also in patients with small stones. In most studies, however, it had a very high specificity—ie, greater than 95%.8
MRCP has a sensitivity of 82.6% and a specificity of 97.5% in detecting stones in the common bile duct.9 Therefore, normal results on abdominal ultrasonography and MRCP do not completely rule out stones.
Although this patient has a high pretest probability of having common bile duct stones, ERCP should be done only after a thorough review of the previous operative procedure.
Observation and reassurance are not appropriate in a patient with cholangitis, such as this patient, because waiting increases the risk of septicemia.
The patient undergoes ERCP with stone removal
Review of the operative report and discussion with the surgeon confirm that the laparoscopic procedure was uneventful and that intraoperative cholangiography was not done.
Therefore, the patient undergoes ERCP. The major papilla is normal. Cholangiography reveals nondilated common bile and intrahepatic ducts, with faint filling defects in the mid to distal common bile duct. Endoscopic sphincterotomy is performed, and three small stones are extracted from the common bile duct. Repeat balloon-occlusion cholangiography is normal.
The patient tolerates the procedure well and resumes a normal diet and normal activities.
Her pain persists, prompting an emergency room visit
Five days after her ERCP procedure, however, the same burning epigastric pain returns. As before, the pain occurs after eating and does not occur with fasting. At this time, she has no fever or chills.
WHAT IS CAUSING HER PAIN?
3. Which is the most likely cause of her persistent pain?
- Acute pancreatitis after ERCP
- Peptic ulcer disease
- Sphincter of Oddi dysfunction
- Biliary stones
The most likely cause is persistent biliary stones. The common bile duct was recently explored and stones were removed, but she may still have stones in the intrahepatic ducts or in the cystic duct remnant, both of which were unopacified during the ERCP procedure, indicating that either the test was incomplete or a stone is obstructing the passage of contrast. Her persistent symptoms warrant repeating her liver function tests.
Acute pancreatitis is the most common and feared complication of ERCP, and it should be suspected in any patient who develops abdominal pain within 6 hours of the procedure. It is much less likely to develop after 12 hours, however. Risk factors for post-ERCP pancreatitis include patient factors (young age, female sex, history of recurrent pancreatitis), procedural factors (difficult cannulation, minor papilla sphincterotomy), and, less likely, operator-related factors.10–13 In general, the more likely a patient is to have an abnormal and irregular common bile duct or pancreatic duct, the lower the risk of post-ERCP pancreatitis. The importance of operator-dependent factors is not yet clear.10–13
Despite the postprandial pattern of our patient’s pain and her history of gastric ulcer, peptic ulcer disease is unlikely in view of a normal esophagogastroduodenoscopic examination done 4 months earlier, and since she has no recent exposure to NSAIDs.
Sphincter of Oddi dysfunction may explain her symptoms, but she recently underwent endoscopic sphincterotomy, which is regarded as the most definitive treatment.14
WHAT SHOULD BE DONE NEXT?
4. What would be the best next step in her management?
- Repeat ERCP
- MRCP
- Endoscopic ultrasonography
- Observation and reassurance
MRCP is the most appropriate next step, given her recurrent symptoms. Repeat ERCP is not appropriate, since there is no evidence of cholangitis, and since her liver function tests had completely normalized.
A recent systematic review of endoscopic ultrasonography and MRCP for diagnosing choledocholithiasis found both tests to be highly accurate, with no statistically significant differences in sensitivity or specificity between the two.15 However, MRCP has the advantage of being noninvasive and of being able to show intrahepatic stones.
Park et al,16 in a prospective study of 66 patients with primary intrahepatic stones, concluded that MRCP findings were comparable to those of percutaneous transhepatic cholangioscopy, the reference standard for locating intrahepatic stones. The sensitivity, specificity, and accuracy of MRCP for detecting and locating intrahepatic stones were high (97%, 99%, and 98%, respectively).16 However, after sphincterotomy, pneumobilia may create an appearance that can be mistaken for intraductal stones.
She undergoes MRCP
The patient continues to have pain, and she has lost 5 pounds because she is still avoiding eating. At this point, she is beginning to wonder if her symptoms are psychogenic, since all the test results have been normal.
ERCP, MRCP, ULTRASONOGRAPHY?
5. What would be the best next step?
- Reassurance
- Referral to a psychiatrist
- Referral to a pain management clinic
- Endoscopic ultrasonography
- Repeat ERCP
Endoscopic ultrasonography is needed to look for cystic duct stones. Although several tests have shown normal results, the patient’s pain continues as in the previous episodes, making stone disease the most likely cause.
Although no stones were seen on MRCP and ultrasonography, a detailed evaluation for stones in a cystic duct or retained gallbladder remnant was not done satisfactorily.
Reassurance and referral to a psychiatrist or pain management clinic are not appropriate, since an organic cause of her pain has not been completely ruled out.
Findings on endoscopic ultrasonography
Endoscopic ultrasonography is performed and reveals a large (7-mm) stone in the area of the cystic duct remnant or gallbladder remnant (Figure 3). The common bile duct is normal.
CAUSES OF RETAINED GALLBLADDER AND CYSTIC DUCT REMNANT
6. What may have predisposed this patient to a retained gallbladder or cystic duct remnant after her surgery?
- Laparoscopic cholecystectomy
- Not doing intraoperative cholangiography
- Cholecystectomy for acute cholecystitis
- All of the above
All of the above may have contributed.
Postcholecystectomy syndrome can pose a diagnostic and therapeutic challenge, as in our patient. Although it has been reported since the advent of the operation, it is more common after laparoscopic cholecystectomy than after open surgery. One possible cause is stones in a cystic duct remnant, ie, a stub longer than 1 cm.
During open cholecystectomy, the cystic duct is ligated and cut as close to the common bile duct as possible, leaving only a small remnant. In laparoscopic cholecystectomy, it is divided closer to the gallbladder to avoid iatrogenic injury to the common bile duct, leaving a longer remnant. A long cystic duct remnant can be prevented by accurately locating the junction of the gallbladder and the cystic duct during cholecystectomy and by routinely doing intraoperative cholangiography. The presence of stones in a cystic duct or retained gallbladder remnant is a rare cause of postcholecystectomy syndrome, and suspicion is required to make the diagnosis.17–19
We should note that stones may also lurk in the short cystic duct remnant left after open cholecystectomy. In fact, the first case of cystic duct remnant, the so-called reformed gallbladder containing stones, was described in 1912 by Flörcken.20
Intraoperative cholangiography was introduced in 1931 by Mirizzi,21 who recommended its routine use. Since the advent of laparoscopic cholecystectomy in 1988, the routine use of intraoperative cholangiography has been debated. Advocates point to its ability to detect unsuspected calculi and to delineate the biliary anatomy, thus reducing the risk of biliary duct injury.7,22–25 Those who argue against its routine use emphasize the low reported rates of unsuspected stones in the common bile duct (2% to 3%), a longer operative time, the additional cost, and false-positive results that may lead to unnecessary common bile duct exploration. Another argument against its routine use is that most small ductal stones pass spontaneously without significant sequelae.26–28 Surgeons who use intraoperative cholangiography only selectively use it in patients with unclear biliary anatomy and preoperative biochemical or radiologic evidence of choledocholithiasis.
Case continued: She undergoes repeat ERCP
IF STONES ARE DIFFICULT TO EXTRACT
7. If the cystic duct stone were not amenable to endoscopic extraction, what would be the best alternative?
- Extracorporeal shock-wave lithotripsy (ESWL)
- Endoscopic biliary laser lithotripsy
- Repeat laparoscopic cholecystectomy
- All of the above
All of the above are alternatives.
A symptomatic stone in a cystic duct remnant is uncommon and is mentioned in the literature only in case series and case reports.
ESWL is effective for treating bile duct calculi.29 In a cohort of 239 patients with bile duct stones treated by ESWL, Benninger et al30 concluded that endoscopy plus ESWL was a definitive treatment for all patients except one, who subsequently underwent cholecystectomy. Once fragmented, the stones are extracted endoscopically.
Another fragmentation technique that can be offered to patients with stones in the cystic duct that are difficult to extract is contact fragmentation with a holmium laser placed in a transpapillary position under visual guidance.17
Repeat cholecystectomy with removal of stones in the cystic duct remnant (and removal of retained gallbladder remnants and reduction of the cystic duct remnant) has good postoperative results.17,18,31,32
After incomplete cholecystectomy, the cystic duct remnant and the Calot (cystohepatic) triangle are surrounded by inflamed scar tissue, and this was thought to make laparoscopic reoperation difficult.33 However, with advances in surgical technique and increasing experience of surgeons, repeat cholecystectomy can be done laparoscopically. It has now been suggested that laparoscopic exploration to remove the gallbladder remnants is safe and feasible in such patients.34,35
Discharge and follow-up
The patient is discharged home after the procedure. She is still free of symptoms 31 months later.
LESSONS LEARNED
Remnant cystic duct stones are uncommon
The estimated incidence of a retained calculus within the cystic duct remnant after cholecystectomy is less than 2.5%.2,36 In a series of 322 patients who underwent repeat surgery because of postcholecystectomy syndrome, Rogy et al36 found only 8 who had a stone in the cystic duct or gallbladder remnant, and in a series of 371 patients, Zhou el al2 found 4 who had a stone in the cystic duct remnant.
Stones in the cystic duct remnant are difficult to diagnose
Diagnosing stones in surgical remnants of the cystic duct or gallbladder can be difficult. The sensitivity of abdominal ultrasonography in detecting cystic duct stones is low—only 27% in one study, with a specificity of 100% and an accuracy of 75%.37 Ultrasonography may occasionally suggest cystic duct stones by showing an acoustic shadow in the anatomic region of the cystic duct. However, the results should be interpreted with caution.
Determining the accuracy of ERCP and MRCP in detecting cystic duct remnant stones is also difficult, as few cases have been reported and data may be conflicting. In a review of seven patients confirmed to have retained stones in a surgical remnant, Walsh et al17 found that ERCP correctly diagnosed the retained stone in only four out of six patients; MRCP was done in one patient, and it was read as normal.
In three cases of stones in a postsurgical gallbladder remnant, Hassan and Vilmann38 reported that ERCP and MRCP failed to identify the gallbladder remnant in two out of three cases, likely because the remaining structures are small. The diagnosis was finally made by endoscopic ultrasonography, which the authors concluded was a valuable method to visualize a small gallbladder remnant with stones.
Greater suspicion is needed in patients with typical biliary colic after cholecystectomy
Retained gallbladder remnant is described in the literature as a latent complication. The main problem is not the remnant itself but the chance that it harbors retained stones, which can lead to dilatation and inflammation of the remnant.
The patient can develop symptoms of acute cholecystitis or even acute cholangitis if the stone migrates to the common bile duct. Symptoms can develop as early as 2 weeks or as late as 25 years after laparoscopic cholecystectomy.
Endoscopic ultrasonography may be the best way to look for these remnant stones and to evaluate the bile duct and pancreas. Therefore, it should be part of the diagnostic algorithm in the evaluation of postcholecystectomy pain.
Mixed results with ERCP for extracting cystic duct stones
In case reports of cystic duct calculi after cholecystectomy, ERCP by itself has had mixed results. This traditional means of removing stones may succeed, as in our case. However, the success rate depends largely on anatomic factors such as the position of the stone in the cystic duct, the degree of stone impaction, the diameter of the cystic duct, and the number of valves in the duct.17
Stones in the cystic duct that cannot be extracted with ERCP may benefit from fragmentation techniques in situ via holmium laser followed by endoscopic extraction.
Repeat cholecystectomy is generally advised for any residual gallbladder, and it can be done laparoscopically.
- Lehman GA, Sherman S. Sphincter of Oddi dysfunction (postcholecystectomy syndrome). In:Yamada T, editor. Textbook of Gastroenterology. 2nd ed. Philadelphia: Lippincott; 1995:2251–2262.
- Zhou PH, Liu FL, Yao LQ, Qin XY. Endoscopic diagnosis and treatment of post-cholecystectomy syndrome. Hepatobiliary Pancreat Dis Int 2003; 2:117–120.
- Mergener K, Clavien PA, Branch MS, Baillie J. A stone in a grossly dilated cystic duct stump: a rare cause of postcholecystectomy pain. Am J Gastroenterol 1999; 94:229–231.
- Goenka MK, Kochhar R, Nagi B, Bhasin DK, Chowdhury A, Singh K. Endoscopic retrograde cholangiopancreatography in postcholecystectomy syndrome. J Assoc Physicians India 1996; 44:119–122.
- Bodvall B, Overgaard B. Cystic duct remnant after cholecystectomy: incidence studied by cholegraphy in 500 cases, and significance in 103 reoperations. Ann Surg 1966; 163:382–390.
- Bergman JJ, van den Brink GR, Rauws EA, et al. Treatment of bile duct lesions after laparoscopic cholecystectomy. Gut 1996; 38:141–147.
- Nickkholgh A, Soltaniyekta S, Kalbasi H. Routine versus selective intraoperative cholangiography during laparoscopic cholecystectomy: a survey of 2,130 patients undergoing laparoscopic cholecystectomy. Surg Endosc 2006; 20:868–874.
- Gandolfi L, Torresan F, Solmi L, Puccetti A. The role of ultrasound in biliary and pancreatic diseases. Eur J Ultrasound 2003; 16:141–159.
- Al Samaraee A, Khan U, Almashta Z, Yiannakou Y. Preoperative diagnosis of choledocholithiasis: the role of MRCP. Br J Hosp Med (Lond) 2009; 70:339–343.
- Freeman ML, DiSario JA, Nelson DB, et al. Risk factors for post-ERCP pancreatitis: a prospective, multicenter study. Gastrointest Endosc 2001; 54:425–434.
- Cheng CL, Sherman S, Watkins JL, et al. Risk factors for post-ERCP pancreatitis: a prospective multicenter study. Am J Gastroenterol 2006; 101:139–147.
- Mehta SN, Pavone E, Barkun JS, Bouchard S, Barkun AN. Predictors of post-ERCP complications in patients with suspected choledocholithiasis. Endoscopy 1998; 30:457–463.
- Badalov N, Tenner S, Baillie J. The prevention, recognition and treatment of post-ERCP pancreatitis. JOP 2009; 10:88–97.
- Geenen JE, Hogan WJ, Dodds WJ, Toouli J, Venu RP. The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction. N Engl J Med 1989; 320:82–87.
- Verma D, Kapadia A, Eisen GM, Adler DG. EUS vs MRCP for detection of choledocholithiasis. Gastrointest Endosc 2006; 64:248–254.
- Park DH, Kim MH, Lee SS, et al. Accuracy of magnetic resonance cholangiopancreatography for locating hepatolithiasis and detecting accompanying biliary strictures. Endoscopy 2004; 36:987–992.
- Walsh RM, Ponsky JL, Dumot J. Retained gallbladder/cystic duct remnant calculi as a cause of postcholecystectomy pain. Surg Endosc 2002; 16:981–984.
- Tantia O, Jain M, Khanna S, Sen B. Post cholecystectomy syndrome: role of cystic duct stump and re-intervention by laparoscopic surgery. J Minim Access Surg 2008; 4:71–75.
- Palanivelu C, Rangarajan M, Jategaonkar PA, Madankumar MV, Anand NV. Laparoscopic management of remnant cystic duct calculi: a retrospective study. Ann R Coll Surg Engl 2009; 91:25–29.
- Flörcken H. Gallenblasenregeneration mit Steinrecidiv nach Cholecystectomie. Deutsch Z Chir 1912; 113:604.
- Mirizzi PL. La colangiografía durante las operaciones de las vias biliares. Bol Soc Cirug Buenos Aires 1932; 16:1113.
- Soper NJ, Brunt LM. The case for routine operative cholangiography during laparoscopic cholecystectomy. Surg Clin North Am 1994; 74:953–959.
- Cuschieri A, Shimi S, Banting S, Nathanson LK, Pietrabissa A. Intraoperative cholangiography during laparoscopic cholecystectomy. Routine vs selective policy. Surg Endosc 1994; 8:302–305.
- Woods MS, Traverso LW, Kozarek RA, et al. Biliary tract complications of laparoscopic cholecystectomy are detected more frequently with routine intraoperative cholangiography. Surg Endosc 1995; 9:1076–1080.
- Vezakis A, Davides D, Ammori BJ, Martin IG, Larvin M, McMahon MJ. Intraoperative cholangiography during laparoscopic cholecystectomy. Surg Endosc 2000; 14:1118–1122.
- Ladocsi LT, Benitez LD, Filippone DR, Nance FC. Intraoperative cholangiography in laparoscopic cholecystectomy: a review of 734 consecutive cases. Am Surg 1997; 63:150–156.
- Clair DG, Brooks DC. Laparoscopic cholangiography. The case for a selective approach. Surg Clin North Am 1994; 74:961–966.
- Collins C, Maguire D, Ireland A, Fitzgerald E, O’Sullivan GC. A prospective study of common bile duct calculi in patients undergoing laparoscopic cholecystectomy: natural history of choledocholithiasis revisited. Ann Surg 2004; 239:28–33.
- Ponsky LE, Geisinger MA, Ponsky JL, Streem SB. Contemporary ‘urologic’ intervention in the pancreaticobiliary tree. Urology 2001; 57:21–25.
- Benninger J, Rabenstein T, Farnbacher M, Keppler J, Hahn EG, Schneider HT. Extracorporeal shockwave lithotripsy of gallstones in cystic duct remnants and Mirizzi syndrome. Gastrointest Endosc 2004; 60:454–459.
- Demetriades H, Pramateftakis MG, Kanellos I, Angelopoulos S, Mantzoros I, Betsis D. Retained gallbladder remnant after laparoscopic cholecystectomy. J Laparoendosc Adv Surg Tech A 2008; 18:276–279.
- Shaw C, O’Hanlon DM, Fenlon HM, McEntee GP. Cystic duct remnant and the ‘post-cholecystectomy syndrome. ’ Hepatogastroenterology 2004; 51:36–38.
- Rozsos I, Magyaródi Z, Orbán P. Cystic duct syndrome and minimally invasive surgery. [Hungarian] Orv Hetil 1997; 138:2397–2401.
- Chowbey PK, Bandyopadhyay SK, Sharma A, Khullar R, Soni V, Baijal M. Laparoscopic reintervention for residual gallstone disease. Surg Laparosc Endosc Percutan Tech 2003; 13:31–35.
- Clemente G, Giuliante F, Cadeddu F, Nuzzo G. Laparoscopic removal of gallbladder remnant and long cystic stump. Endoscopy 2001; 33:814–815.
- Rogy MA, Függer R, Herbst F, Schulz F. Reoperation after cholecystectomy. The role of the cystic duct stump. HPB Surg 1991; 4:129–134.
- Laing FC, Jeffrey RB. Choledocholithiasis and cystic duct obstruction: difficult ultrasonographic diagnosis. Radiology 1983; 146:475–479.
- Hassan H, Vilmann P. Insufficient cholecystectomy diagnosed by endoscopic ultrasonography. Endoscopy 2004; 36:236–238.
- Lehman GA, Sherman S. Sphincter of Oddi dysfunction (postcholecystectomy syndrome). In:Yamada T, editor. Textbook of Gastroenterology. 2nd ed. Philadelphia: Lippincott; 1995:2251–2262.
- Zhou PH, Liu FL, Yao LQ, Qin XY. Endoscopic diagnosis and treatment of post-cholecystectomy syndrome. Hepatobiliary Pancreat Dis Int 2003; 2:117–120.
- Mergener K, Clavien PA, Branch MS, Baillie J. A stone in a grossly dilated cystic duct stump: a rare cause of postcholecystectomy pain. Am J Gastroenterol 1999; 94:229–231.
- Goenka MK, Kochhar R, Nagi B, Bhasin DK, Chowdhury A, Singh K. Endoscopic retrograde cholangiopancreatography in postcholecystectomy syndrome. J Assoc Physicians India 1996; 44:119–122.
- Bodvall B, Overgaard B. Cystic duct remnant after cholecystectomy: incidence studied by cholegraphy in 500 cases, and significance in 103 reoperations. Ann Surg 1966; 163:382–390.
- Bergman JJ, van den Brink GR, Rauws EA, et al. Treatment of bile duct lesions after laparoscopic cholecystectomy. Gut 1996; 38:141–147.
- Nickkholgh A, Soltaniyekta S, Kalbasi H. Routine versus selective intraoperative cholangiography during laparoscopic cholecystectomy: a survey of 2,130 patients undergoing laparoscopic cholecystectomy. Surg Endosc 2006; 20:868–874.
- Gandolfi L, Torresan F, Solmi L, Puccetti A. The role of ultrasound in biliary and pancreatic diseases. Eur J Ultrasound 2003; 16:141–159.
- Al Samaraee A, Khan U, Almashta Z, Yiannakou Y. Preoperative diagnosis of choledocholithiasis: the role of MRCP. Br J Hosp Med (Lond) 2009; 70:339–343.
- Freeman ML, DiSario JA, Nelson DB, et al. Risk factors for post-ERCP pancreatitis: a prospective, multicenter study. Gastrointest Endosc 2001; 54:425–434.
- Cheng CL, Sherman S, Watkins JL, et al. Risk factors for post-ERCP pancreatitis: a prospective multicenter study. Am J Gastroenterol 2006; 101:139–147.
- Mehta SN, Pavone E, Barkun JS, Bouchard S, Barkun AN. Predictors of post-ERCP complications in patients with suspected choledocholithiasis. Endoscopy 1998; 30:457–463.
- Badalov N, Tenner S, Baillie J. The prevention, recognition and treatment of post-ERCP pancreatitis. JOP 2009; 10:88–97.
- Geenen JE, Hogan WJ, Dodds WJ, Toouli J, Venu RP. The efficacy of endoscopic sphincterotomy after cholecystectomy in patients with sphincter-of-Oddi dysfunction. N Engl J Med 1989; 320:82–87.
- Verma D, Kapadia A, Eisen GM, Adler DG. EUS vs MRCP for detection of choledocholithiasis. Gastrointest Endosc 2006; 64:248–254.
- Park DH, Kim MH, Lee SS, et al. Accuracy of magnetic resonance cholangiopancreatography for locating hepatolithiasis and detecting accompanying biliary strictures. Endoscopy 2004; 36:987–992.
- Walsh RM, Ponsky JL, Dumot J. Retained gallbladder/cystic duct remnant calculi as a cause of postcholecystectomy pain. Surg Endosc 2002; 16:981–984.
- Tantia O, Jain M, Khanna S, Sen B. Post cholecystectomy syndrome: role of cystic duct stump and re-intervention by laparoscopic surgery. J Minim Access Surg 2008; 4:71–75.
- Palanivelu C, Rangarajan M, Jategaonkar PA, Madankumar MV, Anand NV. Laparoscopic management of remnant cystic duct calculi: a retrospective study. Ann R Coll Surg Engl 2009; 91:25–29.
- Flörcken H. Gallenblasenregeneration mit Steinrecidiv nach Cholecystectomie. Deutsch Z Chir 1912; 113:604.
- Mirizzi PL. La colangiografía durante las operaciones de las vias biliares. Bol Soc Cirug Buenos Aires 1932; 16:1113.
- Soper NJ, Brunt LM. The case for routine operative cholangiography during laparoscopic cholecystectomy. Surg Clin North Am 1994; 74:953–959.
- Cuschieri A, Shimi S, Banting S, Nathanson LK, Pietrabissa A. Intraoperative cholangiography during laparoscopic cholecystectomy. Routine vs selective policy. Surg Endosc 1994; 8:302–305.
- Woods MS, Traverso LW, Kozarek RA, et al. Biliary tract complications of laparoscopic cholecystectomy are detected more frequently with routine intraoperative cholangiography. Surg Endosc 1995; 9:1076–1080.
- Vezakis A, Davides D, Ammori BJ, Martin IG, Larvin M, McMahon MJ. Intraoperative cholangiography during laparoscopic cholecystectomy. Surg Endosc 2000; 14:1118–1122.
- Ladocsi LT, Benitez LD, Filippone DR, Nance FC. Intraoperative cholangiography in laparoscopic cholecystectomy: a review of 734 consecutive cases. Am Surg 1997; 63:150–156.
- Clair DG, Brooks DC. Laparoscopic cholangiography. The case for a selective approach. Surg Clin North Am 1994; 74:961–966.
- Collins C, Maguire D, Ireland A, Fitzgerald E, O’Sullivan GC. A prospective study of common bile duct calculi in patients undergoing laparoscopic cholecystectomy: natural history of choledocholithiasis revisited. Ann Surg 2004; 239:28–33.
- Ponsky LE, Geisinger MA, Ponsky JL, Streem SB. Contemporary ‘urologic’ intervention in the pancreaticobiliary tree. Urology 2001; 57:21–25.
- Benninger J, Rabenstein T, Farnbacher M, Keppler J, Hahn EG, Schneider HT. Extracorporeal shockwave lithotripsy of gallstones in cystic duct remnants and Mirizzi syndrome. Gastrointest Endosc 2004; 60:454–459.
- Demetriades H, Pramateftakis MG, Kanellos I, Angelopoulos S, Mantzoros I, Betsis D. Retained gallbladder remnant after laparoscopic cholecystectomy. J Laparoendosc Adv Surg Tech A 2008; 18:276–279.
- Shaw C, O’Hanlon DM, Fenlon HM, McEntee GP. Cystic duct remnant and the ‘post-cholecystectomy syndrome. ’ Hepatogastroenterology 2004; 51:36–38.
- Rozsos I, Magyaródi Z, Orbán P. Cystic duct syndrome and minimally invasive surgery. [Hungarian] Orv Hetil 1997; 138:2397–2401.
- Chowbey PK, Bandyopadhyay SK, Sharma A, Khullar R, Soni V, Baijal M. Laparoscopic reintervention for residual gallstone disease. Surg Laparosc Endosc Percutan Tech 2003; 13:31–35.
- Clemente G, Giuliante F, Cadeddu F, Nuzzo G. Laparoscopic removal of gallbladder remnant and long cystic stump. Endoscopy 2001; 33:814–815.
- Rogy MA, Függer R, Herbst F, Schulz F. Reoperation after cholecystectomy. The role of the cystic duct stump. HPB Surg 1991; 4:129–134.
- Laing FC, Jeffrey RB. Choledocholithiasis and cystic duct obstruction: difficult ultrasonographic diagnosis. Radiology 1983; 146:475–479.
- Hassan H, Vilmann P. Insufficient cholecystectomy diagnosed by endoscopic ultrasonography. Endoscopy 2004; 36:236–238.