大腸直腸癌佔全球癌症死亡的第三位。切除大腸息肉可避免其癌化，進一步降低大腸 直腸癌的發生率及死亡率。對於無莖型息肉(non-pedunculated polyp)，內視鏡粘膜切除術 (endoscopic mucosal resection，EMR) 是一項發展成熟的切除技術。傳統內視鏡粘膜切除術會 在息肉下方粘膜下注射(submucosal injection) 液體以在息肉和固有肌層(muscularis propria) 之 間產生一道緩衝，進而避免切除時的肌層損傷。然而，不完美的粘膜下注射亦可能使圈型電 刀(snare) 更難套住息肉，進而導致切除失敗。水下內視鏡粘膜切除術(underwater endoscopic mucosal resection，UEMR) 在2012 年首次被提出用於切除無莖型息肉而無需粘膜下注射。這 是一種相對簡單的方法。我們回顧了目前關於水下內視鏡粘膜切除術的文獻。水下內視鏡粘 膜切除術應用於大腸息肉切除的確是一項安全、有用、且具有發展潛力的技術。

Colorectal cancer (CRC) is the third major cause of cancer mortality worldwide. Polyp removal reduces CRC related mortality. Endoscopic mucosal resection (EMR) is a standard technique for removing non-pedunculated colorectal polyps. Conventional EMR requires a submucosal injection underneath the polyp to separate polyp and the muscularis propria. However, an imperfect submucosal injection might paradoxically make the snare-capture of a polyp more difficult. Underwater EMR (UEMR) was first described in 2012 as a relatively simple and safe method for resecting non-pedunculated colorectal lesions. The key difference is that UEMR obviates the need for submucosal injection. We have reviewed current literatures about colonic UEMR. There are around 450 UEMRs has been reported and the outcomes of UEMR were generally good. In conclusion, UEMR could be a useful and potential technique for colorectal polyp removal.