Is型大腸sm癌の治療―外科の立場から

Treatment of Is Type Early Colorectal Carcinoma with sm Invasion

要旨　外科的切除を受けた大腸sm癌208例中Is型は99例（47.6％）を占め，最も多かった．初回治療時腸管切除例は83例，内視鏡的摘除後腸管追加切除例は13例で，他の肉眼型よりも内視鏡的摘除が選択されやすい傾向にあった．われわれの分類では，sm₁は脈管侵襲の有無にかかわらず全例n₀で，sm₁は内視鏡的にしろ，外科的にしろ局所切除で十分であると考えられた．腫瘍径が小さくてもsm₂，sm₃の症例は，組織型が高分化腺癌だけよりも高分化腺癌に他の組織型の混在した混在型が多く，リンパ節転移の頻度も有意に高く，術前診断でSM'₂以深が疑われる症例は，腫瘍径から安易に内視鏡的摘除をすべきでなく，初回からD₂郭清の腸管切除を施行すべきである．

　We resected 208 cases of early colorectal carcinoma with sm invasion in our hospital. Ninety-nine cases were Is type, 83 cases were surgically resected initially, and 13 cases (13.3%) were endoscopically treated, then followed by surgical resection. We classified carcinoma with sm invasion into three sub-groups by the depth of invasion: sm₁ was the group of lesions with superficial invasion of the submucosal layer, sm₃ was the group of lesions with deep invasion of the submucosal layer and sometimes invasion contacts with the proper muscle layer, and sm₂ was the intermediate invasion between sm₁ and sm₃. In the sm₁ group, we had no cases of lymph nodes metastasis, therefore local excision was enough to treat sm1 group. The incidences of lymph node metastasis in sm₂ and sm₃ group were 12.8 and 14.3% respectively. Those results suggested that colectomy with lymph node removal would be recommended for the cases of preoperative diagnosis of sm₂ or sm₃.