[Colonoscopy detection of polyps in patients operated on for colorectal cancer. Prospective study]

Subjects operated upon for colorectal carcinoma seem to constitute a population at high risk of a second colorectal malignancy and/or colonic adenoma (polyp). Ninety-four such patients were examined by colonoscopy. Their distribution by age and sex and the location of cancers in the colon were comparable to those reported in the literature. Colonoscopy was performed 12 +/- 6 months after surgery in 52 patients and was complete in 90% of them. Twenty-seven patients (52%) were found to have one or several polyps distributed throughout the colonic frame and varying in size from 2 to 75 mm (75% were less than 10 mm long). The larger the polyp, the more severe the dysplasia. Three malignant polyps were discovered; they were more than 10 mm in diameter. The colonoscopic examination was repeated annually over more than 3 years in 30 patients: at first repeat examination 54% had polyps which were still present in more than 30% at subsequent examinations. It is concluded that patients operated upon for colorectal carcinoma are at high risk of polyps and/or a second colorectal carcinoma and must therefore be followed-up by repeated colonoscopy.