2）ESD（endoscopic submucosal dissection）

Indication and Practical Procures of Colorectal ESD

要旨　大腸ESDの適応病変は，内視鏡的一括切除の適応であるが，スネアによる一括切除が困難な病変である．具体的には，LST-NG，特にpseudo-depressed type，V_I型pit patternを呈する病変，SM軽度浸潤癌，大きな陥凹型腫瘍，癌が疑われる大きな隆起性病変〔全体が丈高の結節集簇病変（LST-G）も含む〕である．他にも，biopsyや病変の蠕動によって粘膜下層に線維化を伴う粘膜内病変，潰瘍性大腸炎などの慢性炎症を背景としたsporadicな局在腫瘍，内視鏡的切除後の局所遺残早期癌も適応となる．これらの適応判断のためには，術前の正確な内視鏡診断が必須で，特に拡大観察が有用である．大腸ESDの現状での問題点は，高度線維化例に対する手技の困難性，内視鏡の操作性不良部位の存在，そして，保険適用されていないことである．しかし，デバイスや内視鏡の改良・開発による手技の簡便化が進み，一般化（標準化）は少しずつ確実に進んでいる．

　Colorectal ESD is currently being developed remarkably with the advance of equipment and procedures. Because of the efficacy of EMR（endoscopic mucosal resection）and clinicopathological characteristics of colorectal tumor, the indication for colorectal ESD has been proposed as follows : 1）Large lesions difficult to remove en bloc with a snare EMR, such as LST-NG（particularly pseudo-depressed type）, lesions showing type V_I pit pattern, and large lesions with protruded type suspected to be carcinoma. 2）Lesions with fibrosis due to biopsy or peristalsis. 3）Sporadic localized lesions chronically inflamed such as ulcerative colitis. 4）Local residual carcinoma after EMR. At present support of health insurance for colorectal ESD is expected confidently. Also, colorectal tumor should be efficiently treated by a treatment method appropriately selected from among EMR, ESD, and surgical resection after precise preoperative diagnosis with techniques such as magnifying colonoscopy.