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A prospective, partly randomized study of the effectiveness of repeated examination of the colon after polypectomy and radical surgery for cancer.

Results of 629 colonoscopies and 130 double-contrast examinations, performed during the first 2 years of a prospective, partly randomized cancer prophylactic programme, are reported. The patients were not more than 75 years old and had no previous diagnosis of adenoma or cancer. Repeated colonoscopy 3 months after polypectomy in 80 patients increased the chance of obtaining a complete colonoscopy from 70% to 86%, and the hepatic flexure was reached in a further 9%. Thirteen had polypectomy during the second colonoscopy. The gain in number of patients with adenomas was highest in those with sessile villous adenomas, carcinoma in situ, and mucosal carcinoma. Repeated colorectal examinations every 6 months in these resulted in recurrence rates of 13 of 33, 3 of 23, and 2 of 15 (18 months), respectively. The same figures for patients with stalked polyps, allocated to examination every 6 months, were 3 of 34, 1 of 21, and 2 of 14. Colonoscopy was also performed within 3 months of radical surgery for colorectal cancer, and 35 of 142 patients had polypectomy. Repeated examinations every 6 months resulted in recurrence rates for adenomas of 11 of 85, 3 of 46, and 1 of 34. One new cancer after 12 months could be treated radically. Five uncomplicated laparotomies were performed after the 629 colonoscopies because of perforation or bleeding.