Key Word(s): 1. submucosal tunneling endoscopic resection; 2. submucosal tumors; 3. upper gastrointestinal tract Presenting Author: MEI DONG XU Additional Authors: JIAN WEI HU, PING HONG ZHOU, LI QING YAO Corresponding Author: HUI LIU Affiliations: Zhongshan Hospital, Zhongshan Hospital, Zhongshan Hospital Objective: To evaluate the clinical value of submucoal tunneling endoscopic resection (STER) for treating PF-02341066 cell line gastrointestinal stromal tumors (GIST)

of the stomach. Methods: The clinicopathological data of 21 cases of gastric GISTs treated with STER from September 2010 to December 2013 were analyzed retrospectively. Results: Of the 23 GISTs, 7 were located in the cardia, 2 in the cardia leaned toward the fundus, 6 in the upper gastric corpus and 8 in the gastric antrum of greater curvature. All the GISTs were diagnosed by EUS-FNA before resection or confirmed by pathology after resection. STER was performed successfully in all cases. The en bloc resection rate was 100%. The average operation time was 48 min (range 35–100 min). The average lesion size was 1.8 cm (range 1.0–3.0 cm). All resected lesions were well-encapsulated and had fewer than 5 mitoses per 50 high-power fields, suggesting a low risk of recurrence. pneumoperitoneum occurred in 6 patients were successfully treated with peritoneocentesis decompression. Pneumothorax

and subcutaneous emphysema occurred in four patients and one patient developed left subphrenic effusion suggesting secondary infection. All of them recovered uneventfully on conservative treatments. No delayed bleeding or GI tract leakage occurred. 3-deazaneplanocin A molecular weight No tumor residual or recurrence was found during follow up period (range 8–38 months). Conclusion: STER is a safe, effective and feasible new method for radical treatments of GISTs in appropriate

positions of the stomach. It can maintain the mucosal integrity of the GI tract and prevent the GI tract leakage. Further studies with more cases and long-term outcomes are awaited. Key Word(s): 1. submucosal tunneling endoscopic resection; 2. gastrointestinal stromal tumors Presenting Author: MEI DONG XU Additional Authors: JIAN WEI HU, PING HONG ZHOU, LI QING YAO Corresponding Author: HUI LIU Affiliations: Amobarbital Zhongshan Hospital, Zhongshan Hospital, Zhongshan Hospital Objective: Rectum is a difficult location for endoscopic resection submucosal tumors (SMTs) originating from the muscularis propria (MP) layer, due to the potential increased risks of perforation and retroperitoneal infection. We previously demonstrated the safety and efficacy of submucosal tunneling endoscopic resection (STER) for upper GI SMTs but the feasibility of STER for the removal of rectal SMTs requires systematic investigation. The aim of the investigation is to evaluate the clinical impact of STER on the removal of rectal SMTs.