Key factors for successful en bloc endoscopic submucosal dissection of early stage gastric cancer using an insulation-tipped diathermic knife

Background/Aims: En bloc endoscopic mucosal resection (EMR) is presently considered to be the treatment of choice for endoscopically resectable early stage gastric cancer (EGC). Although a new EMR technique using an insulation-tipped diathermic knife (endoscopic submucosal dissection using an IT knife: IT knife-ESD) is reportedly suitable for en bloc resection, a failure in en bloc resection (piecemeal resection) can occur. We retrospectively analyzed factors affecting the success rate of en bloc resection by IT knife-ESD. Methodology: A total of 71 gastric lesions were treated by IT knife-ESD. En bloc/piecemeal resection rates were investigated. Twelve potential factors associated with clinicopathological characteristics or procedures were analyzed univariately and multivariately. Results: IT knife-ESD was successfully performed in all 71 lesions. En bloc resection was achieved in 63 lesions (91%), while eight lesions (9%) were removed as two or more fragments (piecemeal resection). The multivariate analysis identified only one independent factor affecting the success rate of en bloc resection: the second-half period of procedure application. The en bloc resection rate was not associated with the tumor location/site, tumor size, specimen size, and ulceration within the tumor. Conclusions: Much experience with IT knife-ESD may resolve the tumor-related technical difficulties. It is true for this advanced procedure that endoscopist experience is highly likely to be a critical factor for treatment success. We consider that IT knife-ESD for EGC is feasible and safe when performed by experienced endoscopists.