Endoscopic submucosal dissection of gastric neoplasia involving the pyloric channel by retroflexion in the duodenum

Background: Tumors involving the pyloric channel have been considered as difficult lesions for successful endoscopic resection. We studied the feasibility of endoscopic submucosal dissection (ESD) using retroflexion in the duodenum to resect the gastric neoplasia involving the pyloric channel. Aim: To compare the treatment outcomes of a new ESD technique using retroflexion to those without retroflexion in the duodenum. Methods: Twenty-four cases of gastric neoplasia involving the pyloric channel were resected by ESD. In 14 cases, ESDs were performed from both the antrum and duodenal bulb using retroflexion (retroflexion group). In ten cases, ESDs were performed conventionally only from the side of the antrum (conventional group). We compared the outcomes between the two methods. Results: There was no complication regarding retroflexion in the duodenum. In the retroflexion group, the en bloc and complete resection rate was 100%, respectively. The rate of complete resection was significantly higher in the retroflexion group than in the conventional group (P = 0.01). In the conventional group, three patients with early gastric cancer underwent additional subtotal gastrectomy for positive lateral margin, and one patient with perforation was treated additionally by surgical repair. In the retroflexion group, microperforation and pyloric channel stenosis occurred in one patient, which resolved with conservative treatment. Conclusions: Tumors involving the pyloric channel could be successfully resected by ESD using retroflexion in the duodenum without severe complication. This technique appears to be a feasible and effective method for the treatment of tumors involving the pyloric channel.