Su1294 FEASIBILITY AND EFFICACY OF NON-EXPOSED ENDOSCOPIC WALL-INVERSION SURGERY (NEWS): A RETROSPECTIVE ANALYSIS IN 50 GASTRIC LESIONS

Abstract

In endoscopic full-thickness resection with or without laparoscopic assistance, intentional perforation of the gastric wall which is unavoidable during the procedure may cause bacterial contamination as well as tumor-cell seeding particularly in ulcerated submucosal tumors (SMTs) or cancers. To avoid these risks, we have developed a non-exposure technique of laparoscopy-assisted endoscopic full-thickness resection, called non-exposed endoscopic wall-inversion surgery (NEWS). In this study, we retrospectively investigated the feasibility and efficacy of NEWS for gastric SMTs. Indication of NEWS included intraluminal or intramural growth-type gastric SMTs that were clinically diagnosed as gastrointestinal stromal tumors ≤3 cm in size, regardless of the existence of ulcerative findings; or cT1N0 single early gastric cancers (EGCs) ≤4 cm in size, except for an absolute indication for endoscopic resection (cT1aN0 intestinal-type, ≤2 cm). NEWS was performed as follows: laparoscopic sero-muscular incision after endoscopic submucosal injection, laparoscopic sero-muscular suturing with the lesion inverted, endoscopic muco-submucosal incision, and transoral retrieval. In EGCs, sentinel node navigation surgery was combined by using RI and indocyanine green injection. If stained sentinel nodes (SNs) had no metastasis by intraoperative histological assessment, NEWS with sentinel node basin dissection was conducted. The feasibility and efficacy of this technique was investigated by assessing short and middle term outcomes. NEWS was performed in 50 cases, including 41 SMTs and 9 EGCs between August 2013 and November 2017. The mean tumor size was 23.6 mm. In all cases, the procedure was completed in a mean procedural time of 202.6 min in SMT cases and 304.0 min in EGC cases, respectively, with 1 intraoperative perforation (2.0%). Final histological diagnoses were gastrointestinal stromal tumor (23), gastric cancer (8), leiomyoma (5), ectopic pancreas (5), neurinoma (3), no residual cancer after endoscopic resection (1), and others (5). R0 resection rate in 39 tumors was 97.4%. The mean discharge duration was 7.6 days following treatment. During the mean observational period of 24.5 months, overall and disease-free survival rates were 98% and 100%, respectively. In 1 EGC case who underwent NEWS with left gastric artery basin dissection, severe stasis because of adhesion to the peritoneum occurred, which required distal gastrectomy on the postoperative day 77. NEWS for gastric SMTs and EGCs appeared to be both feasible and safe. This non-exposed full-thickness resection technique by collaborative use of endoscopy and laparoscopy may be a useful option for minimally invasive local resection even for ulcerated SMTs or cancers without risk of tumor cell seeding due to the intentional perforation of the gastric wall.