Adjuvant postoperative radiation therapy in the management of adenocarcinoma of the colon.

Between April 1976 and January 1981, 80 patients with completely resected adenocarcinoma of the colon who were at high risk for local tumor recurrence received adjuvant postoperative irradiation to the tumor bed. Doses of 4300 to 6300 cGy were delivered to the tumor bed, with no chronic toxicity in 70 of 80 patients. Only two patients required operative intervention for treatment complications. Treatment protocol, selection criteria, and details of irradiation are discussed. Actuarial local failure rates at 3 years were 6%, 5%, 17%, 43% for Stages B2, B3, C2, and C3, respectively, and actuarial survival rates at 3 years were 84%, 84%, 73%, and 49%, respectively. The survival figures for Stages B3, C2, and C3 appear superior to published historic controls as well as to data from the study institution, and suggest an advantage to the use of adjuvant radiation therapy in patients with moderately advanced colonic carcinomas.