Current Status of Endoscopic Resection for Superficial Nonampullary Duodenal Epithelial Tumors

Endoscopic resection (ER) is becoming the first choice of treatment for treating superficial nonampullary duodenal epithelial tumors (SNADETs), but ER procedures for SNADETs remain challenging because of the difficulty experienced in maneuvering the endoscope toward the thin duodenal wall, which results in a high rate of adverse events. Although several ER methods were used to overcome these technical difficulties and complications, ER methods for SNADETs are not standardized. A new technique, underwater endoscopic mucosal resection (UEMR), was developed recently in a western country, and its usefulness was reported. Beginning in 2014, we were the first to use UEMR for SNADETs in Japan. Thus, in our experience, we would propose an indication of the various ER methods for SNADETs according to the lesion size.

Endoscopic mucosal resection (EMR) and UEMR were effective and safe for small lesions (≤20 mm), but for large lesions (>20 mm), piecemeal removal of lesion by EMR and UEMR had high incidence of recurrence and adverse events. Especially, piecemeal EMR could cause delayed perforation. Cold snare polypectomy was useful for small lesions (≤10 mm), but further study of its recurrence is warranted. Endoscopic submucosal dissection (ESD) achieved a high complete resection rate regardless of the lesion size, but its rate of adverse events, including morbid complications, was high. Thus, after ESD for large lesions, secure prevention method for adverse events, such as closure of the wound by laparoscopic-endoscopic cooperative surgery, should be required. Key Messages: ER methods for treating SNADETs were proposed based on the lesion size. For large lesions, prophylactic methods for adverse events should be implemented.