Increasing numbers of patients with mucosal polyps of the rectum and colon are being seen each year at the Lahey Clinic. This is due primarily to the increase in the number of patients being examined by sigmoidoscopy—regardless of symptoms—by us and by our consultants, as a part of every complete physical examination. Since we believe that adenomatous mucosal polyps are true tumors and may undergo malignant change, it follows that tumors of this type should be removed or destroyed when discovered. Pathologically, we classify epithelial tumors of the colon and rectum as (1) benign mucosal polyps, (2) mucosal polyps with atypical epithelial hyperplasia, (3) mucosal polyps with foci of carcinoma, and (4) carcinoma. Dr. Shields Warren,1in our earlier presentation before this Section of the American Medical Association in 1939, reported that in a series of over 800 cancers of the colon and rectum studied at that time, 12%