ENDOSCOPIC Nd: YAG LASER TREATMENT FOR DEPRESSED GASTRIC EARLY CARCINOMA

-A PREOPERATIVE STUDY-

Abstract

Endoscopic Nd: YAG laser irradiation was applied preoperatively to eight endoscopically diagnosed depressed early carcinomata of the stomach in eight patients, and the effect of Nd: YAG laser irradiation was investigated in the resected specimens . Four lesions which were diagnosed as mucosal carcinoma were irradiated almost completely. Surgery revealed no metastasis in these four patients . Histopathologic study of the resected specimen in one minute carcinoma revealed no malignat cells, which suggests that Nd: YAG laser irradiation for such carcinoma has become the treatment of choice, instead of surgical resection. Histopathologic study of the other three resected specimens disclosed minimal mucosal carcinomatous residues in one part of the circumference of the laser-induced ulcer, which demonstrated the difficulty of accurately aiming the laser at the entire area of the depressed early carcinoma . Radical cure for such lesions, however, may be achieved by additional laser irradiation. Four lesions chould only be partially irradiated with Nd : YAG laser . Three out of them were considered to have submucosal invasion and the remaining case was diagnosed as a large mucosal carcinoma, exceeding 3 cm in diameter. All these four cases showed no evidence of any metastasis upon operation. Histopathologic study of the former three lesions showed carcinomatous residues at the deep submucosal layer of the laser-induced ulcers, and the latter showed a large mucosal carcinoma at the circumference of the laser-induced ulcer. These results demonstrated that endoscopic Nd: YAG laser irradiation as a curative method of early carcinoma is not available for either a carcinoma invading the deep submucosal layer or a large mucosal carcinoma exceeding 3 cm in diameter. Hematemesis and melena as a complication of Nd: YAG laser irradiation was encountered in one patient three days after the procedure, but it was not serious and blood transfusions were not required. Although no free perforation was encountered in these eight patients, partial disruption of the proper muscle as an effect of Nd: YAG laserirradiation was recongnized in one resected specimen . Therfore, excessive laser irradiation onto the depressed type of early carcinoma should be avoided and the power of the Nd : YAG laser should be limeted to under 50W with the pulse setting at 0.51.0s.