How important is rigid proctosigmoidoscopy in localizing rectal cancer?

Background Colonoscopic localization of rectal and rectosigmoid tumors may be inaccurate. Rigid proctosigmoidoscopy has been suggested as an adjunctive technique to accurately localize rectal tumors as it may alter treatment options. Methods A retrospective review was performed of patients with rectal and rectosigmoid cancer from 2001 to 2006. Patients were stratified into 1 of 4 anatomic regions based on colonoscopic localization of the tumor. The distances of the tumor from the anal verge by colonoscopy were compared with distances obtained via rigid proctosigmoidoscopy. Results Rigid proctosigmoidoscopy localization likely changed the treatment options in 21% of lower rectal tumors, 14% of middle rectal tumors, 38% of upper rectal tumors, and 29% of rectosigmoid tumors. Overall, this modality impacted 25% of patients. Conclusions Rigid proctosigmoidoscopy localization of rectal tumors can significantly change treatment options and should be performed on all patients with colonoscopic localization of a cancer thought to be in the rectosigmoid or rectum.