The rate of adenocarcinoma in endoscopically removed colorectal polyps

The purpose of this study was to determine the rate of cancer in a modern series of colorectal polyps. All pathology reports from colon and rectal polyps from 1999 to 2002 were reviewed. Reports of bowel resections, cancer-free polyps, and polyp-free mucosal biopsies were excluded. Polyps were grouped by size, and the rate of adenocarcinoma was determined. x2 was used for analysis. A total of 4,443 polyps were found, of which 3,225 were adenomatous [2,883 (89.4%) tubular adenomas, 399 (9.3%) tubulo-villous adenomas, 32 (1.0%) villous adenomas, and 11 (0.3%) carcinomas]. The rate of adenocarcinoma by size was 0.07 per cent for polyps <1 cm, 2.41 per cent for polyps 1-2 cm, and 19.35 per cent for polyps >2 cm, representing significantly fewer cancers for each category of polyp size than the accepted standard. The rate of carcinoma in colon polyps is much lower than previously thought and currently stated in many texts. These data do not alter the recommendations for polyp removal, however, failure to retrieve a specimen in a polyp <1 cm in size is unlikely to have an adverse outcome because the chances of malignancy are very low.