早期胃癌術後残胃の内視鏡サーベイランス

Prolonged Endoscopic Surveillance of Gastric Remnant Cancer after Early Cancer Surgery

要旨　早期胃癌に対して切除範囲の狭い手術を行う機会が増し，これらの患者は術後長期生存が期待できる．しかし，早期胃癌術後の残胃をどのように内視鏡サーベイランスするか明確となっていない．1985年から2001年までに1,487例の早期胃癌患者に対して胃部分切除を行い，31例の残胃癌患者が診断された．残胃癌半数の壁在は小彎であり，1例を除き胃腸吻合部から離れて存在していた．22例が早期癌，9例が進行癌であり，残胃早期癌では前回の内視鏡検査から診断時の内視鏡検査までの間隔が平均729日（2.0年）と，進行癌の2,602日（7.1年）より有意に短かった．1,487例中797例（53.6％）が3年間隔での定期的サーベイランス内視鏡検査を受けており，22例の残胃癌が診断された．Kaplan-Meier法による残胃癌累積罹患率は，術後5年では2.4％，10年では5.6％，15年では8.3％と算出された．10年以上の長期サーベイランスでも残胃癌が発見されなかった120例と比較すると，残胃癌が診断された初回病巣には分化型腺癌，同時性多発癌の割合が高かった．H. pylori感染率は残胃癌背景粘膜では初回癌手術時より減少した．早期胃癌術後の残胃癌の内視鏡的サーベイランスは手術後すぐに開始し，2～3年間隔で可能な限り長期間続けることが望ましい．検査時には吻合部から離れた小彎に注意を注ぐことが重要である．

　The aim of this article was to clarify the incidence of gastric remnant cancer after operation for early gastric cancer and to develop surveillance programs for patients partially gastrectomized in order to detect these remnant cancers at the early stage.

　A total of 31 out of 1,487 patients gastrectomized for early gastric cancer between 1985 and 2001 were diagnosed as having gastric remnant cancer. All gastric remnant cancers except one lesion were found distant from the site of the anastomosis and, in half of the patients, the cancers were located on the lesser curvature. In 22 patients the cancers were detected in the early stage and in9patients in the advanced stage. The interval from the preceding examination to diagnosis was shorter in the patients with early cancer than those with advanced cancer (p＜0.01).

　In 797 patients, the interval between endoscopic examinations was periodic. Among these patients, 22 patients were diagnosed as having gastric remnant cancer. The cumulative five-year prevalence rate was estimated as 2.4％, the ten-year prevalence rate as 5.6％ and the fifteen-year prevalence rate as 8.3％. Gastric remnant cancer was more often detected significantly in patients whose initial tumors were multiple or microscopically differentiated type. The prevalence of H. pylori infection was found to decrease in the gastric remnant after the initial surgery.

　Periodical surveillance endoscopy for gastric remnant cancer is recommended after operation for early gastric cancer, particularly in patients whose cancers are microscopically differentiated type. It may be advisable to repeat examinations at two to three year intervals and special attention should be focused on the lesser curvature distal from the anastomotic site.

　1) The Department of Surgery, Fukui Prefectural Hospital, Fukui, Japan

　2) The Department of Pathology, Fukui Prefectural Hospital, Fukui, Japan