Adenomas and hyperplastic polyps in screening studies.

A survey is given of colorectal polyps detected in a prospective randomized screening study with the fecal occult blood test. It is demonstrated that colonoscopy in persons with positive Hemoccult-II tests results in detection of and removal of a higher number of adenomas than among controls. The strategy may, therefore, possibly be followed by a reduction of the incidence of colorectal cancer. Screen-detected adenomas were most often in males and were larger than among controls; they were most often in the sigmoid colon, whereas the rectum was the most frequent location for adenomas in controls. Eight percent of persons with screen-detected adenomas had some symptoms, which could be referred to adenomas, in contrast to 50% among controls. Hyperplastic polyps served as markers for adenomas in persons with positive Hemoccult-II as well as in controls with adenomas detected by colonoscopy; however, most persons with adenomas had no hyperplastic polyps. Endoscopic polypectomy did not result in any severe complications, but surgical removal in 2 of 22 patients proved fatal. The results presented are compared with those of other prospective randomized trials. The optimistic view--that the incidence of cancer may be reduced by polypectomy in persons with positive Hemoccult-II tests--stresses the importance of securing optimal colonoscopy service.