Radiation therapy for rectal carcinoma.

Rectal adenocarcinoma is a radiosensitive tumor. Radiation therapy can be safely given with acceptable tolerance during treatment. In clinically operable patients, this pretreatment appears to increase long-term survival by 43% or better. In symptomatic patients with primary inoperable recurrent disease, control of complants is possible in more than 80% of the patients, and colostomy is avoided in many. Finally, selected patients with inoperable cancer because of limited spread or nonresectable cancer, can be rendered operable by aggressive but tolerable pretreatment with supervoltage radiation. The possibility of long-term survival of such "bad" cases could possibly be enhanced.