Natural Orifice Endoscopic Surgery (NOTES) Techniques for Full Thickness R0 Endoscopic Resection of Deep Seated Subepithelial Tumors (SETs): First U.S. Cases

Abstract

Introduction: Most UGI SETs are GISTs, potentially malignant tumors. Many guidelines recommend surgery for suspected GISTs ≥2 cm and endoscopic surveillance of those <2 cm. This approach creates a large burden of surgery and endoscopy for small SETs the majority of which are low-risk. This situation motivated endoscopists, mostly from Asia, to use ESD to “enucleate” muscularis propria (MP) based SETs. However, such enucleation may leave microscopic residual tumor within the MP. Recently, pioneering Asian centers reported two endoscopic techniques that achieve R0 en bloc resection of MP-based SETs: submucosal tunnel endoscopic resection (STER)- an offshoot of peroral endoscopic myotomy utilizing the submucosal tunnel method to ensure secure closure of the full-thickness defect in the wall of the GI tract, and endoscopic full-thickness resection (EFTR)-direct full thickness resection with closure of the defect with clips or sutures. We report possibly the first series of EFTR and STER in the U.S. Methods: Procedures were performed from 4/2012-6/2014. Data were retrieved from a prospectively maintained database. 33 resections (26 EFTR, 7 STER) were performed by a gastroenterologist with extensive ESD/POEM experience. Results: Mean age 58 (18-84). ASA Class I 12%, II 70%, III 18%. Anesthesia: General 45%, propofol 55%. SET location: 6 esophagus, 22 stomach, 2 colon, 3 rectum. 17 GISTs, 8 leiomyomas, 2 pancreatic rests, 1 schwannoma, 1 leiomyosarcoma and 4 other. Mean size 22 mm (10- 55). Mean resection time 72 minutes (21-220). Closure: endoclips 30%, endoscopic suturing 49%, both 21%. Most patients admitted mainly for observation. Complete en bloc resection achieved in 91%. Piecemeal resection in 3 patients (2 pancreatic rests, 1 5cm GIST). Adverse events: 2 needle decompression of capnoperitoneum, 3 bleeding requiring prolonged endoscopic hemostasis with 2 requiring transfusion, 3 patients 12-24 hour ICU observation, 2 patients required laparoscopic “standby” for immediate assistance that was not needed, 1 patient required laparoscopic conversion due to left gastric artery abutting tumor and 1 balloon dilation of stricture at tunnel closure site. Mean LOS 1.5 days (1-3). Conclusion: Unlike traditional ESD, EFTR and STER achieve en bloc R0 resection of MP-based SETs and represent a NOTES alternative to laparoscopic wedge resection. The excellent outcomes probably reflect our extensive experience with POEM, advanced closure techniques, and ESD for SETs. Advantages include: 1. Incision-less approach 2. “Wedge” resection of SETs at locations where laparoscopic “wedge” resection is challenging or impossible such as the GE junction, esophagus and gastric cardia 3. Definitive diagnosis and complete resection obviating any further endoscopic surveillance for low risk lesions. Disclosure - Stavros Stavropoulos: Boston Scientific Consultant.