Abstract
The aim of this study is to report the efficacy and safety of endoscopic photodynamic therapy (PDT) with hematoporphyrin derivatives (HpD) and Argon dye laser for 53 lesions of 50 patients with tumors of the stomach and colon. The effect of PDT was histologically examined in a case of gastric adenoma, 8 cases of early gastric carcinoma, 2 cases of colonic adenoma and a case of colonic carcinoma. In the remaining cases, the local curability was evaluated by a follow-up biopsy. The efficacy of the initial treatment was 88% for 8 cases of gastric adenoma, 67% for 30 cases of early gastric carcinoma, and 43% for 7 therapeutic failure of Nd : YAG laser. After repeated treatment, 77% of the cases of early gastric carcinoma and 71% of the therapeutic failure of Nd : YAG laser are thought to be tumor-free at the present. The efficacy of the initial treatment was 76% for 17 cases of polypoid or protruded type of lesion, in which the depth of tumor invasion of all but one was estimated to be intramucosal, compared with 61% for 28 cases of flat or depressed type of lesion, 11 of which were thought to have submucosal invasion of the tumor. Photodynamic therapy with a power of 300 mW and the approximate total energy delivered per square centimeter of more than 90 joules seems to be effective for superficially invaded tumor, but curative effects can be hardly expected in cases of fungating tumor or tumor invaded through the muscle layer. The effect of the majority of colonic tumors was partial. The technical difficulty of administering sufficient light en-efce was an another cause of incomplete treatment. Improvement of irradiation equipment, such as the one which has a 360 degree divergent angle shown in this report, is necessary to improve the efficacy of PDT. No serious complications of PDT were encountered, but side effects of HpD such as skin rash and dermatitis to be treated were noted in 22% of the cases.
