早期胃癌の経内視鏡的レーザー治療―病理の立場からの適応と問題点

A Clinicopathological Study on Endoscopic Treatment of Gastric Carcinoma by Laser

要旨　過去4年間，本院で早期胃癌と診断され，レーザー照射治療がなされた22例28病巣について，生検材料および切除標本を用いてレーザー治療の適応および治療成績に及ぼす因子についての検討を行った．Ⅰ型およびⅡa型早期胃癌の治療成績が極めて良好であるのに対し，陥凹型未分化型癌のそれは不良であった．レーザー照射治療を積極的に早期胃癌の治療として用いる場合の癌の状態は，最大径2cm以下の粘膜内癌で，組織学的に胃体部の未分化型癌，および生検組織が粘液結節性腺癌，髄様癌，腺扁平上皮癌であるものを除外した癌であるとみなされた．

　Recently, endoscopic treatment of gastric carcinoma by laser has been applied to patients having early carcinoma whose gastrectomy is not done by some reasons. During the past four years,28 gastric carcinomas in early phase have been endoscopically treated by laser at our hospital (Table 1).

　In this study, these 28 lesions were examined histopathologically in order to establish indicative condition of carcinoma for laser therapy as well as to find the cause of failure of laser therapy in these lesions.

　Four out of twenty eight lesions were resected after laser therapy (Nos. 25, 26, 27, 28 in Table 1), and the other twenty four have been followed up endoscopically after laser therapy. Eighteen lesions have not been observed to be recurrent after five to fifty two months (twenty five months on the average) of trace. In this investigation, the results show that macroscopic type, depth infiltration and histological type of tumor play important role on the recurrence rate of laser therapy. The recurrence rate is minimal in Types Ⅰ and Ⅱa, followed by Type Ⅱc. Recurrence rates of intramucosal carcinoma and differentiated carcinoma are quite lower than those of carcinoma infiltrating submucosa and undifferentiated carcinoma, respectively. The main causes of failure of laser therapy are thought to be due to insufficient laser effect on the deep cancerous tissue and incomplete irradiation which causes leaving cancerous tissue in the irradiation field.

　It may be concluded that the endoscopic coagulation therapy by laser is expected to have high cure rate in intramucosal carcinoma smaller than 2 cm in diameter except the undifferentiated carcinoma arising from the fundic gland mucosa where latent linitis plastica type carcinoma sometimes grows and vertical invasive rate is higher than the other parts. Furthermore, when the biopsy specimen shows muconodular, medullary or adenosquamous carcinoma pattern, laser therapy is not indicated because they strongly suggest advanced carcinoma. Otherwise, the accurate diagnosis of boundary and depth infiltration of carcinoma before irradiation and the even irradiation over all of the cancer surface without leaving cancerous tissue are the most important factors for successful treatment.