Chromocolonoscopy for the Detection of Flat Adenomas in Routine Colorectal Cancer Screening.

The proposed research aims to determine the prevalence, size, shape and histology of flat colorectal neoplasms in a cohort of asymptomatic, average-risk individuals presenting for screening colonoscopy. Patients will be randomized to either conventional colonoscopy or chromocolonoscopy, where the entire colon will be sprayed with indigocarmine dye and examined in the usual manner. The primary outcome will be the total number of adenomas detected, with special attention to the subgroup of flat and depressed lesions. To promote the generalizability of the results, neoplasms will be described according to standard Western and Japanese classification schemes.