[Effect of radiotherapy against advanced carcinoma of the rectum]

In treating advanced carcinoma of the rectum, we have actively used radiotherapy as an adjunct to surgery to enlarge the group of patients indicating surgery and improve the remote results. Of total 423 patients with rectal cancer treated by us in the past 16 years, 202 patients (47.8%) received radiotherapy. Preoperative radiotherapy was performed on 90 of these patients, postoperative radiotherapy on 73 patients, preoperative plus postoperative radiotherapy on 15 patients, and radiotherapy alone on 24 patients. The present study is mainly concerned with preoperative radiotherapy. The purpose of preoperative radiotherapy is to increase the number of patients suitable for surgery. We selected Dukes-C cases without distant metastasis as indications for preoperative radiotherapy, and treated them by 2-step irradiation with 3,000-6,000 rads using Linac after 2 weeks of preoperative observation. The gross and histologic evaluation of the results of irradiation permitted us to conclude that over 3,000 rads was necessary for preoperative radiotherapy. Comparison of the results between preoperative radiotherapy and control groups showed that local recurrence occurred in 6.7% of the radiotherapy group and 9.0% of the control, and 5-year-survival rate was 62.7% and 53.2% respectively, with prognosis improved in the radiotherapy group.