Endoscopic Submucosal Dissection (ESD) isBeing Accepted as a New Procedure of Endoscopic Treatment of Early Gastric Cancer

摘要

Endoscopic treatment of early gastrointestinal cancers has been shown to be effective in cure of mucosal malignancies without lymph node metastasis. Endoscopic mucosal resection (EMR) designed to remove mucosal lesions by section through the submucosa is the most important technique for endoscopic treatment of early gastric cancers (1, 2). According to gastric cancer treatment guidelines issued in March 2001 by the Japanese Gastric Cancer Association (JGCA), EMR should be indicated for patients with small mucosal cancer and no concomitant lymph node metastasis (3). Intestinal type (well and/or moderately differentiated adenocarcinoma and/or papillary carcinoma) mucosal cancers without evidence of ulcer or ulcer scar measuring less than 2 cm in diameter for the superficially elevated (Ila) type, or less than 1 cm in diameter for the flat (lib) and depressed (He) types are included in EMR indication. En-bloc resection is preferable because of the risk of residual cancer left behind EMR. En-bloc resectionwas achieved in 76% of EMR cases from analysis of 12 major institutions in Japan (4). Although various EMR techniques have been developed for the purpose of removing gastric lesions easier, the guideline indicates that 2cm is maximum cancer size of en-bloc resection (4-6). However, gastric mucosal cancers with a diameter of more than 2 cm with no lymph node metastasis have been detected. For example intestinal mucosal cancers without ulceration and involvement of the lymphatic or venous vessels have practically no risk of lymph node metastasis irrespective of tumor size (7). New technique has been required to expand the indications for EMR in selected situations that have no risks of lymph node metastasis. The recently developed EMR procedure, endoscopic submucosal dissection (ESD), makes en-bloc resection possible for mucosal cancers greater than 2cm in diameter (8-12).