深達度からみた大腸ESDの実際と限界

Practice and principles of Colorectal ESD

要旨　ESDを安全確実に再現性をもって施行するには，粘膜下層の血管網を適切に処理し，血管網と固有筋層間の層に至ることが重要である．さらに，この剝離深度を維持することで出血・線維化などの困難例に対処することが可能になる．また，ESDにおいて最も重要なことは，根治性の判断に必要な癌の浸潤距離・様式や脈管侵襲の有無をも評価可能な質の高い切除標本を得ることである．適切な剝離深度での切除は，質の高い切除標本を得ることにもつながる．

　ESD（endoscopic submucosal dissection）has enabled en-bloc resection of early-stage gastrointestinal tumors with negligible risk of lymph node metastasis, regardless of tumor size, location and shape. However, ESD is a relatively difficult technique compared with conventional EMR（endoscopic mucosal resection）, requiring a longer time for the procedure and potentially causing more complications. For a safe and reproducible procedure for ESD, the appropriate dissection of the ramified vascular network at the level of the middle submucosal layer is required in order to reach the avascular stratum just above the muscle layer. The horizontal approach to maintain the appropriate depth for dissection beneath the vascular network enables treatment of difficult cases with large vessels and severe fibrosis. The most important aspect of ESD is the precise evaluation of the curability of the lesion for which it is used. The horizonted approach can also secure the quality of the resected specimen with sufficient depth from the submucosal layer.