早期胃癌の外科的治療

Surgical Treatment of Early Gastric Cancers

要旨　早期胃癌の治療は，近年癌の進行度に応じた治療法が検討され，変革期を迎えている．早期胃癌の1cm前後のⅡa，Ⅱcに内視鏡的切除（ER）が行われ，他方，早期胃癌に対する各種の縮小手術の適応は，多くはERの適応に含まれるものであって，ERの適応外の2～3cmのⅡa，Ⅱcに対しては，ERの組織学的深達度診断のうえに立つ胃局所切除を提示した．早期胃癌の治療の適応を，Ⅱa（分化型腺癌）では，2cm以下はER，Ⅱcでは分化型癌，未分化型癌を問わず，1cm以下はER，2～3cmの症例では，ERの深達度がm，sm（＋）であれば，組織型を問わず局所切除の適応で，ERでsm（++）の症例では，大きさを問わず，胃切除の適応であろう．ERによる癌遺残例に対しても，ERの組織学的深達度がm，sm（＋）であれば，胃切除でなく積極的に胃局所切除を行うべきである．

　The choice of treatment of early gastri ccancer, depending on the size and the depth invasion of tumor, has changed recently. Endoscopic resection (ER) has been applied to type Ⅱa and Ⅱc early gastric cancers whose lesions are 1 cm or less in size. The indication for limited surgery for early gastric cancer includes tumors resectable by ER. Type Ⅱa and Ⅱc early gastric cancers over 2 cm or more in size are out of indicatio for ER. However, we first perform ER for diagnosis of depth invasion, then patients undergo local gastric resection. Based on our study, we propose the choice of treatment as follows: 1) ER is indicated for Ⅱa (differentiated adenocarcinoma) less than 2 cm in size and Ⅱc (differentiated and poorly differentiated adenocarcinoma) less than 1cm in size. 2) Local resection is recommended for lesions 2 to 3 cm in size with mucosal or minimal submucosal invasion. 3) When specimen from ER reveals a lesion has moderate and massive submucosal invasion, gastrectomy is recommended regardless of size of the tumor. 4) When cancer cells remain in a stomach with mucosal or minimal submucosal depth invasion after ER, local resection is the treatment of choice instead of gastrectomy.