Endoscopic mucosal resection and endoscopic submucosal dissection for early gastric cancer: Current and original devices.

Compared with endoscopic submucosal dissection (ESD), endoscopic mucosal resection (EMR) is easier to perform and requires less time for treatment. However, EMR has been replaced by ESD, because achieving en bloc resection of specimens > 20 mm in diameter is difficult with EMR. The technique of ESD was introduced to resect large specimens of early gastric cancer in a single piece. ESD can provide precise histological diagnosis and can also reduce the rate of recurrence, but has a high level of technical difficulty, and is consequently associated with a high rate of complications, a need for advanced endoscopic techniques, and a lengthy procedure time. To overcome disadvantages in both EMR and ESD, various advances have been made in submucosal injections, knives, other accessories, and in electrocoagulation systems.