PREVALENCE OF PROXIMAL COLONIC POLYPS IN AVERAGE-RISK ASYMPTOMATIC PATIENTS WITH NEGATIVE FECAL OCCULT BLOOD-TESTS AND FLEXIBLE SIGMOIDOSCOPY

Background: Proximal colonic adenomas were found in 13% to 37% of pati ents without distal adenomas who underwent colonoscopy, Fiberoptic fle xible sigmoidoscopy (FFS) was not performed prior to colonoscopy in al l studies except one, The proximal colon at colonoscopy was defined as that portion of the colon proximal to either the descending-sigmoid j unction or 60 cm from the anus while withdrawing the colonoscope, Thes e estimates may not reflect exact colonic location when a 60 cm length sigmoidoscope is fully inserted, Therefore, the aim of our study was to determine the prevalence of proximal colonic neoplasms in asymptoma tic patients with average risk for colon cancer, aged 50 years and ove r, with negative fecal occult blood tests and without adenomas at FFS, Methods: Colonoscopy was performed in 80 patients without and 95 pati ents with adenomas at FFS. Polypectomy was done using hot biopsy force ps or snare cautery. Results: Twenty-four proximal colonic adenomas (1 9 <1 cm and 5 greater than or equal to 1 cm) were found in 18 of 80 pa tients (23%) with normal FFS compared with 39 proximal colonic adenoma s (32 <1 cm and 7 greater than or equal to 1 cm), in 28 of 95 patients (29%) with adenomas at FFS (p = 0.31), In patients with normal FFS, t here were 20 tubular, 2 tubulovillous, and 2 villous (1 with severe dy splasia) adenomas, In patients with adenomas at FFS, there were 31 tub ular, 5 tubulovillous, and 3 villous (1 with severe dysplasia) adenoma s, Conclusions: Proximal colonic adenomas are found in up to one fourt h of asymptomatic average-risk patients with negative fecal occult blo od test and both with and without adenomas at FFS. The adenomas in bot h groups have similar size, histology, and location. Severe dysplasia is rarely present.