2. History of the LECS technique

Although surgical local resection with laparotomy or laparoscopic surgery is performed for gastric submucosal tumor (SMT), it is difficult when tumors are small or have an intramural growth pattern. It is difficult to determine the appropriate incision line from the abdominal cavity side, so excessive gastric resection might result in transformation or stenosis. LECS is a newly developed technique, first reported by Hiki et al. in [20] for local resection of GIST. This procedure is further categorized into CLER, which is an approach that combines ESD and laparoscopic gastric resection to determine the incision line, to resect the tumor and to close the stomach wall. As LECS can minimize the resected region and preserve the function of the stomach after surgery, the procedure was added to the national insurance list in Japan in 2014, and subsequently rapidly diffused throughout the surgical community [21–24]. Further applications of LECS then developed, so the first version is named classical LECS to distinguish it from subsequent modified LECS techniques. Classical LECS involves whole layer resection using laparoscopy and endoscopy. However, this technique may lead to contamination of and seeding of tumor cells into the peritoneal cavity, especially when the tumor is associated with an ulcer or epithelial lesion. To prevent peritoneal spread, modified LECS procedures now include inverted LECS with crown method [25], nonexposed endoscopic wall-inversion surgery (NEWS) [26] and a combination of laparoscopic endoscopic approaches to neoplasia with a nonexposure technique (CLEAN-NET) [27].
