Abstract
Endoscopic photodynamic therapy (PDT) for 34 cases (37 lesions) of stomach and colorectal tumors was presented. The effect of PDT was histologically examined in 7 cases of early gastric carcinoma, 1 case of gastric adenoma and 2 cases of colonic tumor. Residual carcinomas were found in 2 cases of early gastric carcinoma, one in the submucosal layer at the distal part of the irradiated area, the other focally at the margin of the laser-induced ulcer. In the case of colonic carcinoma, distal part of the tumor retained. Technical difficalty in complete visualization en-face at the time of laser irradiation was thought to be a major cause of incomplete treatment.
