2）pSM癌の治療方針（大腸癌治療ガイドライン2005/2009）

Pathologic Diagnosis of Endoscopically Resected pSM Colorectal Carcinomas for their Clinical Management, in Therapeutic Guideline for the Colorectal Carcinoma 2005/2009

要旨　内視鏡的摘除pSM癌の治療方針決定には，摘除標本の病理診断が重要な役割を担っている．「大腸癌治療ガイドライン（2005年版）」では，内視鏡的治療で根治が期待されるSM浸潤量が1,000μm未満までに拡大された．同ガイドライン2009年版では新たな病理診断項目として，“粘液癌”と“簇出”が追加された．同ガイドライン2009年版では，以下の治療方針が推奨されている．「追加腸切除」 : 垂直切除断端陽性．「追加腸切除を考慮」 : 垂直切除断端陰性でも，（1）低分化腺癌・印環細胞癌・粘液癌，（2）SM浸潤度1,000μm以上，（3）脈管侵襲陽性，（4）簇出Grade 2，3のいずれかが認められた場合．「経過観察」（内視鏡的治療で根治が期待される）: 垂直切除断端陰性で，（1）乳頭腺癌・管状腺癌，（2）SM浸潤度1,000μm未満，（3）脈管侵襲陰性，（4）簇出Grade 1，の4項目すべてが満たされた場合．

　各病理診断項目の評価法と問題点および今後の課題について述べた．

　Pathologic diagnosis plays an important role in the clinical management of endoscopically resected pSM colorectal carcinomas. The Therapeutic Guideline for colorectal carcinoma published in 2005 stated that the depth of SM invasion which can be expected to be cured by endoscopic treatment alone was indicated as up to 1,000μm. The guideline revised in 2009 added “mucinous carcinoma” and “tumor budding” to the list requiring pathologic diagnosis. The guideline of 2009 indicated the following clinical implications for endoscopically resected pSM colorectal carcinomas. Additional radical surgery is required if the submucosal margin is cancer-positive. Follow up（expected to be cured by endoscopic treatment alone）is required if the following four pathologic conditions are present, 1）papillary or tubular adenocarcinoma, 2）SM depth of less than 1,000μm, 3）negative vascular invasion, 4）tumor budding Grade 1. Additional radical surgery is to be considered if any of the following four pathologic conditions are observed, 1）poorly differentiated adenocarcinoma, signet ring cell carcinoma, mucinous carcinoma, 2）SM depth of 1,000μm or more, 3）positive vascular invasion, 4）tumor budding Grade 2 or 3. Evaluation of each the pathologic factors, their problems and future perspectives are described.