Future directions of duodenal endoscopic submucosal dissection.

Endoscopic therapies for lesions of the duodenum are technically more difficult than those for lesions of the other parts of the gastrointestinal tract due to the anatomical features of the duodenum, and the incidence rate of complications such as perforation and bleeding is also higher. These aforementioned trends were especially noticeable for the case of duodenal endoscopic submucosal dissection (ESD). The indication for ESD of duodenal tumors should be determined by assessment of the histopathology, macroscopic morphology, and diameter of the tumors. The three types of candidate lesions for endoscopic therapy are adenoma, carcinoma, and neuroendocrine tumors. For applying endoscopic therapies to duodenal lesions, accurate preoperative histopathological diagnosis is necessary. The most important technical issue in duodenal ESD is the submucosal dissection process. In duodenal ESD, a short needle-type knife is suitable for the mucosal incision and submucosal dissection processes, and the Small-caliber-tip Transparent hood is an important tool. After endoscopic therapies, the wound should be closed by clipping in order to prevent complications such as secondary hemorrhage and delayed perforation. At present, the criteria for selection between ESD and EMR vary among institutions. The indications for ESD should be carefully considered. Duodenal ESD should have limitations, such as the need for its being performed by experts with abundant experience in performing the procedure.