Follow-up after colorectal polypectomy. II. Repeated examinations of the colon every 6 months after removal of sessile adenomas and adenomas with the highest degrees of dysplasia.

Fifty-five patients with colorectal sessile adenomas and adenomas with the severest dysplasia were followed up every 6 months with colonoscopy and/or double-contrast enema during 4 years, after a clean colon had been obtained, by repeated colonoscopy within 3 months after piecemeal polypectomy. The repetition at 3 months resulted in detection of two cancers. An overlooked cancer was detected at 1 year, and another cancer was diagnosed between examinations. Risk of new adenomas (19 patients) was related to original size, number, and glandular structure of the polyps. Twelve of the 19 patients had new polyps above the rectum. The 336 colonoscopies were complicated by 3 laparotomies, made necessary by perforation and bleeding. The results suggest that intervals between examinations of patients with the present type of adenomas may be prolonged, and patients are now allocated at random to colorectal follow-up examination every 6 and 12 months.