Screening for colorectal cancers Whats new Colorectal Cancer

Screening for colorectal cancers What’s new?

Colorectal Cancer n n n Suitable for screening High incidence among both male and female 2 nd most commonly diagnosed cancer and 2 nd most common cause for cancer death in Hong Kong* Benign adenomatous polyps as premalignant stage Removal of polyps can prevent development into invasive cancer Treatment for invasive cancer well established *HK cancer registry 2006

What’s new? When not to screen? n New screening tools n New guidelines n

Who to screen? n Asymptomatic people > 50 years n Start screening earlier for known high risk groups n Personal history of CRC n Family history of CRC n Known inheritance of genetic cancer syndromes n Inflammatory bowel disease

When not to screen? n n n When harm of screening rises significantly to outweigh the potential benefits First seen in recommendations in year 2008 Consider screening for age 76 -85 years for special cases only n n Cat C recommendation* Do not consider in any case > 85 years n Cat D recommendation* * Screening for colorectal cancer: US precventive services task force recommendation statement

Which screening test to use? USPSTF recommedations 08 n Screening tests recommended (Cat A) n n n Colonoscopy every 10 years Annual sensitive FOBT/ FIT Flexible sigmoidoscopy every 5 years with a mid-interval sensitive FOBT/ FIT Consider stop screening by 75 years old (Cat C/D) Evidence inadequate to assess benefits and harms of CT colonography and fecal DNA testing Ann G. Zauber, Iris Lansdorp-Vogelaar, Amy B. Knudsen, Janneke Wilschut, Marjolein van Ballegooijen, and Karen M. Kuntz Evaluating Test Strategies for Colorectal Cancer Screening: A Decision Analysis for the U. S. Preventive Services Task Force Ann Intern Med. 2008; 149: 659 -669.

Which screening test to use? ACS-MSTF recommendations 08 n For detecting polyps + cancer n n n Colonoscopy 10 yearly Flexible sigmoidoscopy 5 yearly DCBE 5 yearly CT colonography For primarily detecting cancer n n Annual high sensitivity g. FOBT/ FIT Stool DNA test ? Interval n (any positive test would warrant a colonoscopy) * Screening and Surveillance for the Early Detection of Colorectal Cancer and Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Radiology CA Cancer J Clin 2008

Which screening test to use? Asia Pacific consensus 2008 Screening should start at 50 years n Male sex, smoking, obesity and family history are risks factors n Recommended tests n n FOBT (g. FOBT or FIT) n Flexible sigmoidoscopy n Colonoscopy n DCBE and CT colonography not preferred * Asia Pacific Consensus Recommendations for Colorectal cancer screening Gut 2008; 57: 1166 -76

What new tools in the current update? n Immunochemical FOBT (FIT) n Fecal DNA testing n CT colonography

Immunochemical FOBT (FIT) n Proposed advantage n n Detect human globin not subject to false –ve with high dose Vit C Globin digested in upper GI tract, more specific for lower GI tract bleeding Compare with high senstivity g. FOBT n Similar in sensitivity and specificity *Allison JE, et al. Screening for colorectal neoplasms with new fecal occult blood tests: update on performance characteristics. J Natl Cancer Inst 2007; 99: 1462– 1470 *Gopalswamy N et al. A comparative study of eight fecal occult blood tests and Hemo. Quant In patients in whom colonoscopy is indicated. Arch Fam Med 1994; 3: 1043– 1048 *Greenberg PD, et al. A prospective multicenter evaluation of new fecal occult blood tests in patients undergoing colonoscopy. Am J Gastroenterol 2000; 95: 1331– 1338 *Wong BC, et al. A sensitive guaiac faecal occult blood test is less useful than an immunochemical test for colorectal cancer screening in a Chinese population. Aliment Pharmacol Ther 2003; 18: 941– 946 *Smith A, et al. Comparison of a brush-sampling fecal immunochemical test for hemoglobin with a sensitive guaiac-based fecal occult blood test in detection of colorectal neoplasia. Cancer 2006; 107: 2152– 2159 *Levi Z, et al. A quantitative immunochemical fecal occult blood test for colorectal neoplasia. Ann Intern Med 2007; 146: 244– 255

Fecal DNA testing n Variable reported performance n sensitivity 52 -91% , specificity 93 -97% n Better than traditional g. FOBT No conclusive difference with high sensitivity g. FOBT/ FIT Issue of positive f. DNA but –ve Ix n Newer version now available in market n n not widely tested ? any improvement of performance Best test interval remained unknown n Recommeded by manufacturer to be 5 yearly *Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Fecal DNA versus fecal occult blood for colorectal-cancer screening in an average-risk population. N Engl J Med 2004; 351: 2704– 2714

CT colonography Radiological method to examine the colon n Multidetector CT scanners with 2 D and 3 D reconstruction n Bowel preparation as for colonoscopy n Stool and Fluid tagging to reduce false positive rates n Colonic distension during scan n Need training for radiologist for interpretation n

CT Colonography n Preferred over barium enema n Colon proximal to an obstructing lesion n incomplete colonoscopy n Accuracy n Similar to colonoscopy for lesions >10 mm n (sensitivity n Inferior 94% specificity 96% for >10 mm)* for smaller polyps and flat polyps n (sensitivity 89% specificity 90% for <6 mm)* Pickhardt PJ, Choi JR, Hwang I, et al. Computed tomographic virtual colonoscopy to screen for colorectal neoplasia in asymptomatic adults. N Engl J Med 2003; 349: 2191 -200

CT Colonography n Outstanding issues n reporting of polyps 5 mm or smaller n threshold polyp size for colonoscopy referral n intervals for repeated examinations n radiation exposure n extra-colonic findings and implications n Reported 7 -15% of CT colonographies - ASGE Techology Committee Update on CT colonography Gastrointestinal endoscopy 2009 Vol 69 No 3 - USPSTF recommendation statement 2008

Recommendations Tests ACSMSTF USPSTF modeling Other modeling Asia Pacific Consensus Traditional g. FOBT N Y suboptimal mixed Y Sensitive g. FOBT/FIT Y Y Y f. DNA 5 yearly Y insufficient evidence not evaluated suboptimal not evaluated FS 5 yearly Y Y suboptimal Y CTC 5 yearly Y insufficient evidence not evaluated Y not preferred C’scope 10 yearly Y Y Y

Recommendations Tests ACSMSTF USPSTF modeling Other modeling Asia Pacific Consensus Traditional g. FOBT N Y suboptimal mixed Y Sensitive g. FOBT/FIT Y Y Y f. DNA 5 yearly Y insufficient evidence not evaluated suboptimal not evaluated FS 5 yearly Y Y suboptimal Y CTC 5 yearly Y insufficient evidence not evaluated Y not preferred C’scope 10 yearly Y Y Y

Recommendations Tests ACSMSTF USPSTF modeling Other modeling Asia Pacific Consensus Traditional g. FOBT N Y suboptimal mixed Y Sensitive g. FOBT/FIT Y Y Y f. DNA 5 yearly Y insufficient evidence not evaluated suboptimal not evaluated FS 5 yearly Y Y suboptimal Y CTC 5 yearly Y insufficient evidence not evaluated Y not preferred C’scope 10 yearly Y Y Y

Recommendations Tests ACSMSTF USPSTF modeling Other modeling Asia Pacific Consensus Traditional g. FOBT N Y suboptimal mixed Y Sensitive g. FOBT/FIT Y Y Y f. DNA 5 yearly Y insufficient evidence not evaluated suboptimal not evaluated FS 5 yearly Y Y suboptimal Y CTC 5 yearly Y insufficient evidence not evaluated Y not preferred C’scope 10 yearly Y Y Y

Recommendations Tests ACSMSTF USPSTF modeling Other modeling Asia Pacific Consensus Traditional g. FOBT N Y suboptimal mixed Y Sensitive g. FOBT/FIT Y Y Y f. DNA 5 yearly Y insufficient evidence not evaluated suboptimal not evaluated FS 5 yearly Y Y suboptimal Y CTC 5 yearly Y insufficient evidence not evaluated Y not preferred C’scope 10 yearly Y Y Y

Take Home Message Different recommendations for colorectal screening n Most consistently recommended for screening of colorectal cancer n n Colonoscopy 10 yearly n High sensitivity g. FOBT/ FIT yearly n New technology coming up n Stool DNA n CT colonography