Endoscopic resection for laterally spreading tumor (LST) -(endoscopic submucosal dissecion (ESD) vs. endoscopic mucosal resection)-

Interventions: Group A. ESD group 1. The solution of a mixture of Glyceol and 1% 1900-KDa hyaluronic acid preparation is injected into the submucosal layer. 2. Mucosal incision is started with the knife for ESD. 3. The lesion is resected with submucosal dissection.
Group B. EMR group 1. The solution of normal saline is injected into the submucosal layer. 2. The lesion is resected with an electrosurgical snare.
Primary outcome(s): the incidence of local recurrence after endoscopic resection
Study Design: Parallel Randomized