Radiation therapy alone or in combination with chemotherapy in the treatment of residual or inoperable carcinoma of the rectum and rectosigmoid or pelvic recurrence following colorectal surgery. Radiation Therapy Oncology Group study (76-16).

Between 1976 and 1981, 147 patients with residual, inoperable, or locally recurrent carcinoma of the rectum were randomized to receive either radiation (XRT) alone or XRT plus chemotherapy (concomitant 5-FU during XRT and maintenance 5-FU + MeCCNU). An initial field received 4,500-5,100 rad in 5-6 weeks, with a boost field dose to a maximum of 7000 rad/8 weeks (maximum 6,000 rad/7 weeks with chemotherapy), dependent on findings of special small bowel films. One hundred twenty-nine patients were evaluable (65 XRT, 64 XRT + chemo). There were no statistically significant differences between treatments with respect to overall survival, complete remission rate, time to disease progression, local failure rate, or radiation dose distribution. Median survival was 17 months for XRT, 18 months for XRT + chemo; the 2-year survival probability was 36% for XRT, 44% for XRT + chemo. Initial performance status was a significant prognostic factor for both survival and time to disease progression. A trend was observed favoring the combination treatment for patients with residual disease. Treatment complications were greater for the combined modality arm than for radiation alone. Twenty-seven patients (22%) were alive at last data analysis, with no evidence of disease (NED) from 2-51 months (30 months median). Patients with resection of gross disease before or after irradiation had a much better result than those with gross residual or without any resection, but the relative influence of patient selection versus impact of surgery remains unclear.