Screening Colonoscopy: Is it on the Brink of Extinction ?

1. Screening Colonoscopy: Is it on the Brink of Extinction ? Patrick R. Pfau, M.D. Associate Professor Chief of Clinical Gastroenterology University of Wisconsin School of Medicine and Public Health

2. Learning Objectives • To determine the present state of colorectal cancer screening with colonoscopy • To identify the “threats” to screening colonoscopy • To determine what will keep colonoscopy an important colon cancer screening modality

3. 305,866,7775

4. Is screening colonoscopy going extinct ? • Number of colonoscopies has risen steadily in U.S. while Flex-Sig and Barium Enemas has dropped significantly • Harewood G, Clin Gastroenterol Hepatol 2004 • Colonoscopy most common endoscopic procedure performed in U.S. • Sonnenberg A, GIE 2008 • Screening colonoscopy has increased greatly in Medicare population • Fenton JJ, Am J Prev Med 2008 • Increased CRC screening rates primarily result of screening colonoscopy • Phillips K, Med Care 2007

5. Why screening colonoscopy is the king ? • Two large cohort studies (Winawer, NEJM 1993 and Citarda Gut 2001) have demonstrated significant reductions in colon cancer incidence if colonoscopy with polypectomy are performed • FOBT and sigmoidoscopy that lead to colonoscopy with polypectomy have been shown to significantly reduce colorectal cancer mortality • Colon cancer incidence decreased 2.6 %/year since 1998 with sharp decrease since 2002 (Cancer 2007)

7. What are the “threats” to screening colonoscopy ? • iFOBT • Fecal DNA • CT Colonography • Ourselves – how we perform screening colonoscopy

8. Quantitative immunochemical FOBT – Threat #1 • Improved detection of hemoglobin as compared to guaic based FOBT tests • Immunochemical FOBT testing uses antibodies to human globin expressed in colorectal bleeding.

9. Colon Cancer Screening with iFOBT • 94 % sensitivity for cancers and 67 % for advanced adenomas with approximate 90% sensitivity in high risk individuals (Levi Z, Ann Int Med 2007) • 25 – 27 % sensitivity for advanced adenomas but different iFOBT tests vary (Hundt ,Ann Int Med, 2009) • 90 % - 256 % more sensitive than guaic based FOBT for advanced neoplasia ( Guittet L, Gut 2007) • 7 % sensitivity for adenomas < 10 mm (Morikawa T Am J Gastro 2007) • iFOBT should replace gFOBT in screening for patients who will not or cannot have total colon screening – only helps screening colonoscopy

10. Fecal DNA Analysis - Threat #2 • Adenoma and carcinoma cells contain altered DNA that are shed continuously • Multitarget DNA stool assay • Requires entire stool specimen (must be mailed)

11. Fecal DNA and colon cancer screening • Ahlquist D, Gastroenterology 2000 studied patients with colon cancers, large adenomas, and normal colons • Sensitivity of 91% for colon cancer, 82% for large adenomas and a specificity of 93% Imperiale T, NEJM 2004 studied patients in a screening population • Poor sensitivity for invasive cancers (52%) and advanced polyps (15%) • Ahlquist D, Ann Int Med, 2009, Zou H, Gastroenterology 2009 • Latest assays approximately 2-3 times more sensitive than earlier assays – detected 46 % - 59% advanced adenomas • Fecal DNA analysis will only lead to more colonoscopies and more positive/therapeutic colonoscopies

12. CT Colonography (CTC) – Threat # 3 • Joint guideline from the ACS, US Multi-Society Task Force on CRC, and the ACR (Levin B, Gastro 2008) • CTC is comparable to colonoscopy for detection of polyps of a significant size • Panel concludes that there are sufficient data to include CTC as an acceptable option for CRC screening • ACRIN study (Johnson C, NEJM, 2008) • CTC should have role in CRC screening for average risk patients

13. Does CTC screening affect screening with colonoscopy ?(Are our jobs in jeopardy ?) • Van Dam J, Gastro 2004 • CTC would likely have a “significant” impact on the practice of gastroenterology in America • Hur C, Clin Gastroenterol Hepatol 2004 -Mathematical Model • 9-22 % reduction in colonoscopies • Reduction based on referral rate from CTC

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19. Impact of CTC on Colonoscopy • Schwartz D, AJG 2007 • A fully operational third party insurer covered CTC program had no effect on colonoscopies performed, screening colonoscopies performed, colonoscopies with polypectomy performed, nor requests for screening colonoscopy after greater than 3 years

21. Bucky and Colon Cancer Screening

22. CRC screening at UW five years after initiation of CTC program (2008)

23. Why has CTC not affected screening colonoscopy ? • CTC does not replace colonoscopy but simply adds an additional test (there are a lot of colons out there) • CTC has distinct disadvantages compared to colonoscopy • If CTC employs “selective polypectomy” it will not lead to an additional # of therapeutic colonoscopies

25. Extinction of Screening Colonoscopy – Ourselves to Blame ? Threat # 4 • Complication (Perforation) rate • .016 % (1 in 6000) Rathgaber S, GIE 2006 • .2 % (1 in 500) Kim D, NEJM 2007 • .85 per 1000 Rabeneck L, Gastro 2008

26. How good are we at detecting adenomas ? • Adenoma detection rate (ADR) • Barclay R, NEJM 2006 – ADR ranged from .1 to 1.05 at institution • Chen AJG 2007 – patients detected with adenomas ranged from 16-41 % between 9 academic gastroenterologists with ADR varying from .21 - .86

27. Benson, M Dig Dis Sci, 2009

28. How can screening colonoscopy be saved ? • Do a better colonoscopy • Training • Time • Technology • Use competing technologies to benefit screening colonoscopy • Work to get more patients screened no matter the method – everything feeds into colonoscopy eventually • Do not become addicted to screening colonoscopy

29. Doing a Better Screening Colonoscopy • Training • ASGE and ACGME – 140 colonoscopies during GI fellowship • Chak A GIE 1996 – Trainees do not achieve competence at 100 colonoscopies • Lee S GIE 2008 – competence in screening colonoscopy requires more than 150 cases • Spier B GIE/DDW 2009 • No trainee reached independence (>90% cecal intubation) after 140 cases • First fellow to achieve > 90% cecal intubation took over 300 cases • Not until 500 colonoscopies were performed that all fellows achieved > 90 % cecal intubation rate

30. Doing a Better Screening Colonoscopy • Time • Sanchez W, AJG – Colonoscopy procedure time correlates with 3 – fold difference in polyp detection • Barclay R NEJM 2006 – Colonoscopists who had withdrawal times > 6 min. found more patients with adenomas (23.8 % vs. 11.8 %) and advanced adenomas (6.4 % vs. 2.6 %) • Simmons D Aliment Pharmacol Ther 2006 – Longer withdrawal time correlated with more polyps being found – suggested 7 minute withdrawal • Barclay R Clin Gastroenterol Hepatol – Implementation of 8 minute withdrawal time increased number of adenomas detected (34.7 % vs. 23.5 %) • Sawhney M, Gastro 2008 – increasing withdrawal times to 7 minutes did not increase adenoma detection rate

31. Benson, M Dig Dis Sci, 2009

32. Doing a Better Screening Colonoscopy • Technology • Colonoscopes • Self-propelling scopes • Retro scopes • Capsule colonoscopy • Wide - angle • Auxillary Devices • Hoods and caps • Chromoendoscopy • Imaging • Narrow Band Imaging • Magnifying • Autofluorescence • Optical Coherence Tomography • Confocal Microscopy • Added last night – better sedation with propofol

36. Screening Colonoscopy – Is it Dying ? • External Threats – No real threats at present • No test matches colonoscopy for CRC screening • External threats actually benefit colonoscopy • Internal Threats – Do a better colonoscopy • Know and improve your own personal complication and adenoma detection rates – each gastroenterologist has to meet a minimum of standards