Low Yield of Repeat Colonoscopy at 5 Years in Average-Risk People

How often should patients undergo screening colonoscopy if their initial exams revealed no polyps or only small distal hyperplastic polyps? Current guidelines recommend a 10-year interval, even though this interval is not supported directly by any observational or clinical trial data (Gastroenterology 2003; 124:544). Instead, the recommendation is based on case-control studies showing 10- to 16-year protection after a single negative sigmoidoscopy and on observational studies showing at least 10-year protection after a negative colonoscopy in a symptomatic patient. In addition, three studies of colonoscopy performed 5 years after an initial negative examination all found the yields to be very low. Now, a fourth study (which is 6 times large…