Endoscopic Mucosal Resection Versus Endoscopic Submucosal Dissection for Colorectal Laterally Spreading Lesions.

EMR and ESD are both effective and safe and are associated with a very low risk of procedure related mortality when performed for colorectal laterally spreading lesions (LSL). Some kind of LSLs have a low risk of submucosal invasive carcinoma (SMIC) or these foci are found in well demarcated areas of the tumor. This is the case of the non-granular flat elevated (LSN-NG-FE) and the LSLs-G mixed subtypes. The investigators aim to assess if piecemeal EMR (the older technique) for LSLs-G mixed type > 30 mm and LSLs-NG FE type > 20 mm is not inferior to ESD (the new treatment) for the need of additional surgery in the mid-term.