[Comparison of surgical therapy and combined irradiation in rectal cancer--first report, effect of irradiation on the tumor. Study Group of Surgical Therapy and Combined Irradiation in Rectal Cancer]

Abstract

In order to establish the best protocol for the treatment of rectal cancers, a cooperative study on preoperative radiation therapy was conducted by 44 institutions in eastern Japan. A total of 166 cases that did not receive preoperative chemotherapy were analyzed, and the following conclusions were obtained. A comparison between two groups of patients, one that had received preoperative irradiation and the other that had not, revealed remarkable tumor regression in the former along with reduction of in rectal stenosis, condition of the border of the lesion, bleeding, constriction and central excavation. There were no significant differences between the two groups in terms of lymph node metastasis. Histological examination based on the criteria established by Oboshi and Shimosato showed radiation effects better than grade II b in 32.1% primary tumors and in 33.3% of metastatic lymph nodes within the radiation field. No significant differences in the incidence of side effects or complications were noted between the two groups.