Surveillance colonoscopy after resection for colon carcinoma.

Periodic surveillance colonoscopy was used to assess 207 asymptomatic patients with a previous history of colorectal carcinoma for 2 to 8 years. Thirty-five percent of the patients had a neoplastic lesion greater than or equal to 5 mm in diameter on initial colonoscopy. Synchronous or metachronous carcinomas were found in 11 patients; and of these second carcinomas, 82% were localized. The risk of a second carcinoma developing did not correlate with a finding of neoplastic polyps on the initial colonoscopy. Six recurrent carcinomas at the anastomosis were demonstrated. The stage of the recurrence correlated well with the stage of the primary carcinoma. Two negative colonoscopies at 1-year intervals were necessary to ensure that the colon had been cleared of neoplastic lesions. This study shows that surveillance colonoscopy in patients with a history of colorectal carcinoma has a high yield and is capable of detecting localized, asymptomatic carcinoma. After two annual colonoscopies fail to show neoplasms, surveillance colonoscopy may be scheduled at 3- to 5-year intervals.