内視鏡的粘膜切除術を施行した胃sm癌の臨床経過―経過観察例の検討

Clinical Courses of Gastric Submucosal Carcinomas Treated by Endoscopic Mucosal Rresection Alone

要旨　内視鏡的粘膜切除術(EMR)後，追加手術を施行せずに経過観察した胃sm癌9例について検討した．切除標本の病理組織学的所見は，組織型は9例中5例がtub1，2例がtub2，papとpor1が各1例で，粘膜内と粘膜下層に存在する癌組織の異型度が明らかに異なる症例がみられた．sm浸潤度は8例がsm1，残りの1例はsm₃で，脈管侵襲は3例に認められた．臨床経過は1例で局所再発，他の1例で異時性多発を認め，いずれも再度EMRを行った．3例が他因病死したが，経過観察中(7～68か月，平均32.3か月)リンパ節再発や遠隔転移を来した症例はなかった．切除標本でsm浸潤を認めた場合には原則的に追加手術を考慮すべきであるが，①sm浸潤の程度が軽度(sm₁)，②sm浸潤部の組織型が高分化型腺癌，③脈管侵襲陰性，の3つの条件を満たす場合には，経過観察が可能と考えられる．

　Nine cases of gastric submucosal carcinomas which were treated by endoscopic mucosal resection (EMR) alone for some reasons were studied. Histopathological classification of the lesions was as follows: five cases of well differentiated adenocarcinoma, two cases of moderately differentiated adenocarcinoma, one case of papillary adenocarcinoma, and one case of poorly differentiated adenocarcinoma (solid type). For the viewpoints of depth of the invasion, eight cases had minute invasion (sm₁) and one case had massive invasion (sm₃). Lymphatic or vascular invasion was seen in three cases. Local residue of cancer cells was detected in one case and new small cancer was found at the different region 18 months after the first EMR, and these two cases were retreated by EMR. Three cases were died of reasons other than cancer (senility: two cases, pneumonia: one case). However, there were no cases that died of recurrence of cancer and had metastasis to lymph nodes or other organs during the follow-up period (7 to 68 months, average 32.3 months). In general, surgical gastrectomy should be recommended for gastric Submucosal carcinoma after EMR, but the possibility of lymph node metastasis can be very low if histopathological findings satisfy following three criteria (1) The grade of submucosal invasion is mild (sm₁), (2) The histological type is well differentiated adenocarcinoma, especially in the submucosa, (3) There is no lymphatic or vascular invasion.