Current status of colonic endoscopic mucosal resection in the west and the interface with endoscopic submucosal dissection.

Endoscopic Mucosal Resection (EMR) is now widely practised by western endoscopists to treat large sessile colonic polyps or laterally spreading tumours. Despite its widespread application, the technique of colonic EMR is not standardised. A lesion specific endoscopic treatment approach is also lacking. For lesions larger than 25mm, EMR is limited by its inability to achieve en-bloc resection. En-bloc resection has many theoretical advantages including more accurate histological assessment, reduced recurrence and potentially curative treatment for low risk submucosal invasive neoplasia particularly in patients with significant co-morbidity. Hence, Japanese endoscopists, having pioneered endoscopic submucosal dissection (ESD) in the upper gastrointestinal tract for the en-bloc resection of superficial neoplasia, now advocate the use of ESD for laterally spreading tumours of the colon greater than 25-30mm. This treatment strategy is not widely accepted or practised in the west and has its own inherent problems. The absence of suitable gastric lesions on which to develop ESD skills is also another significant barrier to the development of colonic ESD. It is also possible that modification and refinement in EMR technique may increase the size limit for colonic EMR.