残胃癌のESD（endoscopic submucosal dissection）

Endoscopic Submucosal Dissection (ESD) of Remnant Gastric Cancers

要旨　endoscopic submucosal dissection（ESD）を施行した残胃癌7例9病変を対象とし，同時期にESDを施行した通常胃癌345例と対比した．残胃癌の腫瘍長径中央値は16mm（5～30mm）であり，通常胃癌の長径中央値16mm（3～145mm）と同値であった．一括切除率は100％であり，通常胃癌での一括切除率97％と比較し有意差はなかった．これら9病変の残胃癌はすべて切除断端陰性であった．残胃癌は狭くスコープの操作性が悪いため通常胃に比してESDは難しかった．特に縫合線上に癌が存在した場合は粘膜下層の線維化が高度で剥離に難渋した．また，剥離中にペッツが露出した場合はペッツへの通電を避ける配慮が必要であった．しかし，直視下に粘膜下層を観察しながら慎重に剥離することで，残胃癌に対してもESDを安全に施行することができた．縫合線上の残胃癌は粘膜下層に強い線維化を伴うため，従来のEMR法では切除が困難であったが，ESDでは安全，確実な切除が可能であった．

　Nine remnant gastric cancers and 345 gastric cancers had been resected, using the endosocpic submucosal dissection method, from Jan. 2000 to Dec.2003.

　The mean tumor size of remnant gastric cancers (RGC) was 16mm (5～30) and that of normal gastric cancers (NGC) was 16mm (3～145mm). One-piece resection rate was 100％ in RGC and 97％ in NGC. Eight RGC's were limited to the mucosal layer but one RGC had invaded the submucosal layer. No local recurrence or metastasis has been detected by endoscopy and CT.

　If the cancer is located on the suture line, fibrosis of the submucosal layer makes it difficult to resect the lesion. The method of snaring with EMR might be impossible in these cases and might cause perforation with strong aspiration. It might be difficult but possible with the ESD method. The most important point when resecting these lesions is to keep a clear visual field of the submucosal layer with a transparent hood and to cut the submucosal fibers with the hook knife.

　The incidence of lymph node metastasis of submucosally invading cancer was 15％ or less. Five-year survival rate of the 80-year-old or more age group was only 61％. The QOL might fall after total gastrectomy, so the treatment method, total gastrectomy or ESD, should be considered carefully.

　1) Gastroenterology, Saku Central Hospital, Nagano, Japan