大腸sm癌のsm浸潤の分析と治療方針―sm浸潤度分類について

Treatment of Colorectal sm-Carcinomas

要旨　大腸sm癌のsm浸潤について，その深達度に従い粘膜筋板位置より固有筋層までを3等分してsm₁，sm₂，sm₃とし，更に横の拡がりを加味して，sm領域の癌の横の拡がりが粘膜部の癌の面に対しごく一部のものをa，50％以上のものをc，中間型をbとして分類した．肉眼形態とsm浸潤度はかなり相関し，Ⅰpはすべてsm_1cまでにとどまり，Ⅰpsはsm₂まで，Ⅰs，Ⅱaはsm_2,3が多い傾向があり，Ⅱa＋Ⅱcはほとんどがsm₃の深層浸潤を示した．n（＋）例は18.2％に認められ，sm_1bより出現し，ly（＋）例も同様であった．深達度が浅くとも横の拡がりのあるsm_1cではly（＋）例が多く治療上注意を要すると思われた．sm_1aでは予後悪性因子はなかった．

　Sixty-one cases with colorectal submucosal (sm) carcinomas, histologically proved, were classified into sm₁, sm₂ and sm₃ according to the level of sm-invasion. The sm₁ carcinomas were further subclassified into a, b and c categories depending on the horizontal extension.

　The gross configuration and level of sm-invasion were well correlated. Ⅰp (pedunculated) type sm-carcinomas (9 cases) were located within sm_1c, Ⅰps (subpedunculated) type (12 cases), within sm₂, Ⅰs (sessile) type (15 cases) and Ⅱa (flat-elevated) type (13 cases) were various, but mainly in sm₃.

　Eleven sm-carcinomas (18.2%) with lymph node metastasis belonged to sm_1b through sm₃. Ⅱa and Ⅱa＋Ⅱc (flat-elevated with depression) type sm-carcinomas had a high rate of lymph node metastasis.

　The gross size of sm-carcinomas was not always correlated to the level of sm-invasion because of frequent involvement by non-malignant or adenomatous element.

　These data indicate that the gross configuration of sm-carcinomas is closely related to their biologic characteristics and that radical operation with lymphadenectomy is necessary for Ⅱa and Ⅱa＋Ⅱc type sm-carcinomas. The policy for treatment of Ⅰp, Ⅰps and Ⅰs type sm-carcinomas should be decided on the basis of histology after polypectomy, and sm_1a carcinoma with well-differentiated histology type and without lymphovascualr invasion may be on further follow-up observation, but most of other sm-carcinomas are considered to necessitate radical operation.