Evaluation of preoperative radiation therapy in operable colorectal cancer

Abstract

Materials and methods: Patients with operable colorectal cancer in the ascending colon, descending colon, and rectum were randomized to 500 cGy before definitive surgery. Patients with stage A and B1 lesions received no further treatment. All patients with stage B2, B3, C1, C2, and C3 received a minimum of 4500 cGy postoperatively.

Results: Three hundred fifty-three patients were registered for the study. Three hundred one patients were available for analyses. Follow-up was a minimum of 5 years on all study patients. The majority of patients had rectal cancer. Complications of treatment were acceptable. Two hundred thirty-one patients had stage B2, B3, C1, C2, or C3 tumors. Estimated 5-year rates for no preoperative therapy versus preoperative therapy were as follows: local recurrence 29% versus 26%; metastasis 41% versus 43%; and survival 54% versus 54%. No statistical benefit was observed for preoperative treatment.

Conclusions: In a prospective randomized trial designed to test the value of low-dose preoperative irradiation followed by surgery and postoperative irradiation, the authors were unable to observe any benefit to low-dose preoperative therapy in patients with unfavorable stages.