Carcinoma in the retained rectum after colectomy for ulcerative colitis.

A carcinoma arising in an excluded rectal stump 18 years after ileostomy and 14 years after subtotal colectomy has been described. Extent of involvement of the colon, age of the patient at onset of colitis, and duration of symptomatology are factors whcih have been shown to influence the incidence of carcinoma complicating ulcerative colitis. Fifty-eight similar cases of carcinoma developing in a retained rectum were collected from the literature. The incidence of this complication is approximately 3 per cent. Rectum-sparing operations do not appear to decrease the incidence of malignant transformation in ulcerative colitis. A decision to retain the rectum after colonic resection for ulcerative colitis must take into account both the significant incidence of malignant transformation associated with all rectum-sparing procedures and also the significant incidence of recurrent symptoms following this procedure.