Colorectal Cancer Screening: Colonoscopy, Potential and Pitfalls. Disclosures: None. CRC: still a major public health problem

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1 Colorectal Cancer Screening: Colonoscopy, Potential and Pitfalls Disclosures: None Jonathan P. Terdiman, M.D. Professor of Clinical Medicine University of California, San Francisco CRC: still a major public health problem Cumulative Mortality from Colorectal Cancer in the General Population, as Compared with the Adenoma and Nonadenoma Cohorts. 1 million cases per year worldwide and ½ million deaths USA 4 th most common cancer ~ 150, 000 cases per year 2 nd most common cause of cancer death ~ 50, 000/yr Lifetime risk is 3-6% Zauber AG et al. N Engl J Med 2012;366:

2 Screening Options FOBT q year Flexible sigmoidoscopy q 5 yrs FOBT and Flexible sigmoidoscopy Colonoscopy q 10 years CT colonography q 5 years Screening Colonoscopy Compelling indirect evidence that this is the best test FOBT studies Flex Sig Studies Polypectomy Studies Cohort studies Screening Colonoscopy: VA Cooperative Study (Lieberman et al. NEJM, 2000) Advanced adenoma in 7.9% Cancer in 1.0% 73% with Stage I or II disease 20% with Stage III and 6% with Stage IV 44% of patients with advanced neoplasia would have been missed by flex sig first screen 30% missed by sig + FOBT Colonoscopy in the real world: The Polyp Prevention Trials 9 studies with > 20, 000 years of patient follow-up Incidence of CRC = /1, 000 person-years Incidence is equivalent to general population and 4 x that in National Polyp Study!!! Gastroenterology 2005;129:34-41 Gastrointest Endosc 2005;61:385-91

3 Impact of colonoscopy on CRC death Baxter NN. Ann Int Med, , 292 CRC deaths and 51, 940 controls among 1.2 million Canadians, OR for death with colonoscopy = 0.69 Left sided cancers, OR = 0.33 Right sided cancer, OR = 0.99 Incomplete Exam Gastro, 2007 Pop-based study in Canada > 300, 000 exams, 13% incomplete Risk Factors Older age Women Prior operation Test in MD office Missed Cancers Gastro, 2007 AN: Left vs. Right Polyps Gupta S, et al. Clinical Gastroenterology and Hepatology 2012; 10: Cancers diagnosed within 3 yrs of colonoscopy Risk Factors Older age Diverticular disease Right sided cancer Internist/Family MD doing the test Test in a MD office

4 Flat & Depressed Polyps Soetikno R, Jama exams, use of dye spray to confirm Prevalence = 9.4% (95% CI, ) OR for cancer = 9.8 Incomplete Polyp Resection Pohl H, Gastroenterology 2012 Prospective study of 1427 patients who underwent colonoscopy 10% inadequately resected Wide range by MD (6.5-23%) Risk Factors Large size: 17% for > 10 mm Serrated polyps: 31% Less than 20 polypectomies/year Advanced Polypectomy Holt BA, Clin Gastro Hepatol, 2012 Biological Variability 51 interval cancers within 5 years of colonoscopy MSI in 30.4% of interval cancers versus 10.3% of others (p = 0.003) Interval cancers 3.7 x more likely to be MSI 27% of interval cancers at previous polypectomy segment Interval cancers 3 times more likely to be R sided Farrar WD Gastro, 2006 Sawhney MS Clin Gastro Hepatol, 2006

5 Doing colonoscopy well Barclay RL NEJM, 2007 Mean adenoma detection rate according to colonoscopic withdrawal times 12 endoscopists doing over 2000 screening exams Range of adenoma detection 9.4% to 32.7% Range of scope withdrawal times 3.1 to 16.8 minutes Detection rate < versus > 6 minutes 11.8% versus 28.3% for any adenoma (p < 0.001) 2.6% versus 6.4% for advanced adenoma (p = 0.005) Cumulative Hazard Rates for Interval Colorectal Cancer, According to the Endoscopist's Adenoma Detection Rate (ADR). Kaminski MF et al. N Engl J Med 2010;362: Benchmarks for GOOD Colonoscopy Adenoma Detection Rate > 25% men, 15% women PLCO data: 2.4 fold risk of interval cancer in those with lowest quartile of ADR vs. highest Documentation of Prep 100% Cecal Intubation >/= 95% Recent population-based study in Canada rate was only 87% Withdrawal Times >/= 6 minutes?

6 Colonoscopy done well Brenner, Ann Int Med, 2011 Population-based case-control study in Germany 1688 CRC cases and 1932 controls Colonoscopy within 10 years 77% risk reduction for CRC 84% for left-sided cancer 66% for right-sided