Colorectal cancer rate and villous adenomas: a fifteen years experience.

Objectives: The purpose of this report is to describe our experience with 586 polipectomies performed on 320 patients. The procedure, the complications, the lesions hystology, and the cancer rate are as well described. Methods: Of 320 patients, only 25 (7.8%) underwent a major surgical resection, 6 following diagnostic colonscopy, 17 after polyp hystology revealed a malignancy and 2 as a complication of polipectomy. The remaining 295 received an endoscopic polipectomy. Results: No mortality was recorded after endscopic resections. Two patients (0.6%) required major surgery due to early bleeding. Of 586 polyps, 8 (1.36%) revealed to be cancer with polyp features, 486 (82.9%) were adenomas and 92 (15.6%) were mixed forms. By considering only adenomas 21 cancers on 486 (4.3%) were found. Five cancers were found on 378 tubular adenomas (1.3%), 8 on 82 tubular-villous adenomas (9.7%) and 8 cancers were found on 26 villous adenomas (30.7%). No cancer was found in non adenomatous forms. The risk of developing colorectal cancer was signi®cantly higher in villous adenomas than other adenomas (p<0.001 Chi2 test). Sex, age and adenomas localization did not affect cancer incidence. Conclusions: Our experience confirm previous reports. Villous adenomas appear to be a major risk factor of developing colorectal cancer when compared to other adenomas. Non adenomatous polyps present a negligible risk of malignancy. Nevertheless colorectal cancer may rarely arise with polyp features in absence of adenomatous tissue.