潰瘍性大腸炎関連腫瘍に対する内視鏡治療の適応とピットフォール

Indication and Pitfalls of Endoscopic Resection for Ulcerative Colitis-associated Neoplasia

要旨●潰瘍性大腸炎関連腫瘍，特にhigh grade dysplasiaやcolorectal cancerに対する標準的な治療は全大腸切除術である．近年，有効な抗炎症薬物治療の増加とともに，サーベイランス内視鏡検査の普及によりdysplasiaや粘膜内癌を内視鏡的に診断することが可能となってきた．当科で“治癒切除”を目的とし，内視鏡的粘膜下層剝離術を施行した潰瘍性大腸炎関連腫瘍の特徴を検討した．水平断端陰性率が低く境界診断が難しいこと，同時多発率が高く見落としやすいことがピットフォールと言える．したがって，周囲生検を行うなど十分に境界診断を検討したhigh grade dysplasiaおよび粘膜内癌で，治療後は4〜6か月ごとの内視鏡検査を行うことが可能な症例が，内視鏡治療の適応と考えた．

　The standard therapy for ulcerative colitis-associated neoplasia, particularly high-grade dysplasia and colorectal cancer, is total colectomy. Because of recent increasing effectiveness of anti-inflammatory drug treatment and surveillance endoscopy, dysplasia and intramucosal cancer can be diagnosed endoscopically. We investigated the characteristics of ulcerative colitis-associated neoplasia that had undergone endoscopic submucosal dissection for the purpose of curative resection. We considered that pitfalls in endoscopic resection for ulcerative colitis-associated neoplasia included difficulty in identifying the demarcation line because of the low horizontal margin-negative rate and the high rate of synchronous tumors. Therefore, the indication for endoscopic resection in high-grade dysplasia and intramucosal cancer is a tumor in which a demarcation line is identified with surrounding biopsy area. Following resection, it was thought that endoscopy every 4-6 months was necessary.