早期胃癌の内視鏡的粘膜切除―一括切除の限界と分割切除の問題点

Endoscopic Mucosal Resection for Early Gastric Cancer, Limitation of Whole Block Resection and Problem of Partial Resection

要旨　内視鏡的粘膜切除（EMR）における切除標本の大きさを分析し，一括切除の成績と，適応拡大するうえで必要となる分割切除の成績とを対比させながら遺残再発を中心に述べ，それぞれの切除法の問題点について検討した．EMRの3原則に従い，EMRを施行したのは171例（一括切除：129例150病変，分割切除：42例43病変）であった．一括切除では遺残再発は12.0％に認められた．遺残再発は，癌の大きさとの関係は認められなかったが，切除断端の所見と関係があった．また，切除標本の大きさはA領域の20mmに比べ，C，M領域で15mmと小さい傾向がみられ，切除の限界があった．一方，分割切除では癌の大きさに比例して遺残再発率は高かった．また，1つの切除標本のみに癌をみた例では再発はなく，2つの切除標本に癌が認められれば13.3％に，3つ以上の切除標本に癌が認められれば25.0％に遺残再発を認め，癌の大きさに伴い多分割することと深い関係があった．分割切除では，一括切除に比較して約2倍の切除標本が得られ，部位による標本の大きさの差はなかったが，病変の再構築は不可能であった．1回目のEMRで引き起こされる胃側の変化は分割切除標本の断端に約3mmの幅で虚血性組織変化としてburnning effectが認められた．

　The cases with early gastric cancer who were treated either by the whole block resection or by the partial resection were analyzed for evaluating the recurrence rates by the size of the resected specimen and the method of EMR. One hundred and fifty lesions of early gastric cancer less than 2 cm in size were resected en block, and the recurrence rate was 12% during the post-EMR follow-up period. The recurrence rate did not correlate with the size of cancer, but was related to the location of cancer the resected specimen of the antrum was bigger than that of the gastric body or the cardia.

　On the other hand, 13.3% of 42 lesions of early gastric cancer less than 3 cm in size which were resected by the piece meal method, was recurred during the follow-up period. The recurrence was related to the size of cancer, although the resected gastric specimen which contained the carcinomatous lesion was big enough. So, we could resect the gastric mucosa widely by the partial resection of EMR, but in such cases it was impossible to confirm the width and depth of invasion pathologically. In conclusion, the partial resection by the piece meal method had better be avoided, because of high recurrence rate for gastric cancer more than 2 cm in size.

　Pathologically, burnning effect on the gastric mucosa by EMR was estimated to be 3 mm in width with ischemic change.