大腸SM癌内視鏡切除標本のSM浸潤度判定の実際と問題点―大腸癌研究会プロジェクト研究から

Diagnosis of the Grade of Submucosal Invasion of Endoscopically Resected Colorectal Submucosal Carcinoma―Practice and Problems

要旨　大腸癌研究会プロジェクト研究の一環として，大腸SM癌内視鏡切除標本のSM浸潤距離および浸潤度判定（浸潤距離1,000μm未満か以上か）の，病理医によるばらつきの現状とその要因を検討した．非有茎性SM癌のSM浸潤距離は，診断者により400μm前後の差異があった．SM浸潤度判定では，"粘膜筋板の変形・走行の乱れ・断片化"例または"筋板消失"例での一致率が低かった（77.8％と85.4％）．有茎性SM癌では，"粘膜筋板錯綜例と非錯綜例"の取り扱いで，病理医により大きな乖離があった．今後，大腸癌治療ガイドラインに示されたSM浸潤度判定法の病理による解釈および実際の運用面での幅を狭めて行く必要がある．

　As a part of a research project by the Japanese Soceity for Cancer of the Colon and Rectum, an investigation was made to elucidate the variation in diagnosis of submucosal invasion distance and its grading (less than 1,000μm or more) by pathologists. In regard to non-pedunculated lesions, the interobserver variation of the diagnosis of invasion distance was around 400μm, and the concordance was low muscularis mucosae in cases of "submucosal carcinoma with deformed musculsaris mucosae" and "submucosal carcinoma with disappearance of muscularis mucosae" (77.8％and 85.4％, respectively). In regard to pedunculated lesions, differentiation of ones with and without complex muscularis mucosae was not consistent among the pathologists. It is thought that variation in the interpretation of the guideline and the standardization of the diagnosis of submucosal invasion distance and its grading is required.