Endoscopice Evaluation of Rediation Effect for Preoperative Irradiation Therapy in Rectal Cancer-Comparison of Histologic and Endoscopic Findings of Radiation Effect-

Thirty four patients with advanced rectal cancer treated by preoperative irradiation were examined endoscopically and histologically. On the bases of the histologic findings all the cases were classified into noneffective group (16 cases) and effective group (18 cases). We tried to establish criteria for endoscopic evaluation of radiation effect composed of the following 5 items; 1) flattening of the marginal wall, 2) smoothing of the crater, 3) removal of the dirty coat of the ulcer bottom, 4) improvement in ease of bleeding, 5) improvement of stenosis. According to each criterion, the radiation effect was evaluated as marked (2 points), moderate (1 point), and little (0 point) change. The total score of each point was defined as endoscopic evaluation. Endoscopic evaluation was 5.4 ± 1.8 in non-effective group and 8.1 ± 1.6 in effective group (p<0.01). So the endoscopic evaluation was found to be correlated with the histologic evaluation. It was thought that the endoscopically revealed changes in the tumor shape could make us assume the histological radiation effect.