THE TREATMENT OF LOCALLY ADVANCED COLON-CANCER

Purpose: The results of therapy for 103 patients with locally advanced colon cancer who received radiotherapy were analyzed to determine the outcome and tolerance of therapy. Methods and Materials: Between 1974 and 1994, 103 patients received radiotherapy and maximal resection of locally advanced colon cancers. Following resection, 50 patients had no residual disease, 18 patients had microscopic residual disease, and 35 patients had gross residual disease, External beam radiotherapy wa s initiated 1 to 4 months following resection except in two patients w ho received preoperative radiotherapy, Treatment was delivered to the tumor bed and adjacent lymph nodes using 4 to 18 IMV X-rays with doses ranging from 16.2 to 60 Gy, Intraoperative electron radiotherapy (IOE RT) was also administered to 11 of the patients with doses ranging fro m 10 to 20 Gy, Chemotherapy was administered to 77 patients, Follow-up in survivors ranged from 0.5 to 17 years (median: 5.8 years). Results : The 5-year actuarial local failure rate was 10% for patients with no residual disease, 54% for patients with microscopic residual disease, and 79% for patients with gross residual disease (p < 0.0001), For pa tients with residual disease, local failure occurred in 11% of patient s receiving IOERT compared with 82% of patients receiving only externa l beam therapy (p = 0.02), The 5-year actuarial survival rate was 66% for patients with no residual disease, 47% for patients with microscop ic residual disease, and 23% for patients with gross residual disease (p = 0.0009), The 5-year survival rate in patients with residual disea se was 76% for patients receiving IOERT and 26% for patients receiving external beam therapy alone (p = 0.04). Conclusions: Patients with lo cally advanced colon cancer who have had a complete resection have a h igh probability of local control after external beam irradiation +/- 5 fluorouracil (SFU)-based systemic therapy, The toxicity of therapy ca n be minimized with attention to treatment technique and dose, Local c ontrol and survival rates in patients with residual disease who receiv ed IOERT appear to be significantly greater than for those patients wh o received external beam radiotherapy therapy alone. Copyright (C) 199 7 Elsevier Science Inc.