Abstract
It is the purpose of this presentation reporting the efficacy and safety of Nd: YAG laser (Olympus Co.) treatment of mucosal tumors of the stomach. Before applying to clinical trials, series of animal experiments were carried out. Firstly, the results indicated that the laser probe with a low beam divergent angle (5°) was applicable to endoscopical use because the working distance was not critically important in determining the depth of tissue damage. Secondly, a multiple pulse with 1 to 2 sec. with 5-sec. cooling interval was less injurious if the same total incident laser energy was applied on any one spot. In final series of experiments, a multiple pulse with 40w of power was applied to an area of canine stomach supposing the irradiation to tumor, and histological consequence was observed. Laser-induced ulcers were usually reepithelized after 2 to 3 weeks and no perforation was complicated. On the basis of these results, endoscopic laser treatment was attemped in 8 cases of borderline lesion and 10 cases of early gastric carsinoma (Type I 1 case, IIa 4 cases, IIc 5 cases) under certain conditions, resulting in complete eradication of the lesion. The effect of laser treatment was confirmed histologically in 4 cases, in which partial irradiation was performed before surgery. The clinical course of the remaining cases was uneventful and no evidence of tumor recurrence has been observed. Endoscopic laser treatment is an available method for patients with broad-based protruded lisions in which snare ectomy might be hazardous, and localized early gastric carcinomas whose surgical risk might be critical, as being weighed against the risk of regional lymphnode metastasis.
