RECTAL-CANCER FOLLOWING COLECTOMY AND ILEORECTAL ANASTOMOSIS FOR FAMILIAL ADENOMATOUS POLYPOSIS

Background: Familial adenomatous polyposis (FAP) has historically been treated by colectomy and ileorectal anastomosis (IRA). Preservation o f the rectum allows the subsequent development of cancer in the rectum . The risk of rectal cancer following ileorectal anastomosis in the Au stralian population has not been published to date. Methods: An audit of the Familial Adenomatous Polyposis Registry of Western Australia wa s undertaken to assess patients who had under gone colectomy and ileor ectal anastomosis. Fifty-five patients ranging in age from 13 to 65 ye ars were studied. Results: Seven patients (13%) developed cancer of th e rectum with a median follow-up of 10 years (range: 1-31 years). Medi an interval to diagnosis of carcinoma of the rectum following colectom y and IRA was 10 years. All patients who developed cancer in the retai ned rectum had rectal polyps. Colon cancer was present in the initial colectomy specimen in 13 patients (of these, five patients developed r ectal cancer). Flat polyps were noted in five patients. Four patients with flat polyps developed cancer of the rectum. Conclusions: Total co lectomy and IRA should be considered as part 1 of a staged procedure i n the patient with FAP. With the exception of the patient with no evid ence of rectal polyps, completion proctectomy should be undertaken wit hin 10 years of the initial colectomy.