病理学的見地からみた大腸sm癌に対する治療方針―内視鏡治療の危険性

A Policy of Treatment for Colorectal Carcinoma with Submucosal Invasion from a Pathologic Point of View

要旨　sm癌のリンパ節転移の危険因子としては，深い深達度（sm₂以上），低い分化度（簇出を含む），リンパ管侵襲の3因子が重要であると考えられる．リンパ節に転移したsm癌の組織像は，①中～低分化腺癌でly（＋），②中分化腺癌でv（＋），③高分化腺癌でly（－），v（－）の3型に大別された．原発巣からだけではリンパ節転移の有無を予測することは完全にはできないので，sm癌であればすべてリンパ節郭清を含めた外科的手術施行が原則であるとわれわれは考える．

　The risk factors of lymph node metastases of colorectal carcinomas with submucosal invasion are considered to be depth of invasion (more than sm₂), poorly differentiated components, and lymphatic permeation. Histologically, the carcinomas with submucosal invasion and lymph node metastases were classified into three types : 1) Moderately to poorly differentiated adenocarcinoma with lymphatic permeation, 2) Moderately differentiated adenocarcinoma with vascular invasion, 3) Well differentiated adenocarcinoma with neither lymphatic permeation nor vascular invasion. It is impossible to predict which carcinoma will metastasize to the lymph nodes. Therefore, all the colorectal carcinomas with submucosal invasion should be treated by surgical resection with lymph node dissection.