subepithelial tumors ( sets ) in the stomach are usually found incidentally during endoscopic examinations . most gastric sets do not cause symptoms and were formerly considered to have a benign nature , such as lipomas , inflammatory fibroid polyps , or several neural origin tumors ( i.e. , schwannomas ) . however , several gastric sets have malignant potential , especially when they originate from the muscularis propria ( mp ) layer , such as gastrointestinal stromal tumors ( gists ) , neuroendocrine tumors ( nets ) , glomus tumors , and even metastastic tumors . thus , removal of gastric sets and histopathologic confirmation are required when gist or net is highly suspected . in this review , we summarize the critical points when planning endoscopic resection of gastric sets as well as the long - term clinical outcomes of endoscopic resection of gastric gist . first , diagnostic yield can be improved by obtaining whole set tissue ; thus , endoscopists can avoid frequent re - examination . second , physicians are able to confidently provide a therapeutic plan to patients according to definite diagnosis ; thus , reassuring patients and reducing their anxiety . third , insurance - related conflicts can be avoided . unfortunately , neither strict guidelines nor widespread acceptance for endoscopic resection as the treatment for gastric sets have yet been established . we cautiously suggest indications for endoscopic resection based on our clinical experiences as follows : gists less than 3.0 cm without positive endoscopic ultrasonography ( eus ) findings ( i.e. , irregular borders , cystic space , ulceration , echogenic foci , and heterogeneity ) or hypoechoic sets less than 3.0 cm . first , the tumor should be smaller than 3.0 to 4.0 cm , even though the exact cut - off limit remains controversial . if the tumor is larger than this limit , endoscopic resection might be technically unavailable or cause serious complications including macroperforation . second , the endoscopic procedure is operator - dependent , because the techniques mentioned above require highly advanced skills and sufficient clinical experience . third , only limited studies including small numbers of patients and short - term follow - up periods have been published and are thus subject to selection biases . table 1 summarizes procedure - related outcomes of endoscopic resection of sets in the upper gastrointestinal tract ( ugit ) . recent guidelines from the national comprehensive cancer network state that if gists are completely resected ( including r1 resection ) , adjuvant therapy with imatinib can be considered , especially for patients with a significant high risk of recurrence ( intermediate or high risk by recent world health organization classifications ) . however , imatinib therapy followed by endoscopic resection is neither approved nor covered by the national health insurance system in korea , and guidelines from the korean gist study group suggest that complete en bloc resection with negative margins should be performed regardless of tumor size ; therefore , even if the tumor is small , endoscopic shell - out procedure or enucleation should be avoided if gist is suspected . further discussion and opinions should be based on clinical outcomes and long - term follow - up data of endoscopic procedures . as technical skills have advanced and novel endoscopic procedures have been developed , complete en bloc endoscopic resection of gastric sets has been reported [ 6 - 17 ] . however , they included only a small number of gastric gists , and their long - term follow - up results have not yet been reported . recent studies have reported no recurrence of gastric gists resected by endoscopic procedure ; however , their follow - up periods were relatively short , ranging from 1 to 2 years . here a total of 249 patients with set in the ugit underwent endoscopic resection in our hospital ; among them , 89 cases were confirmed as gastric gist by histopathologic examination . the most common site of the gastric gists was the gastric body ( 43.3% ) , followed by the cardia ( 22.2% ) and fundus ( 21.1% ) . the mean tumor size was 2.31.2 cm , and most were considered to have originated from the mp layer ( 64.4% ) based on pre - procedural eus findings . most of the tumors were resected by endoscopic submucosal dissection ( 80.0% ) , followed by submucosal tunneling endoscopic resection ( 8.9% ) , and two cases ( 2.2% ) by endoscopic full - thickness resection . the complication rate was 14.4% , including micro- and macroperforation ( 5.6%/4.4% , respectively ) and major bleeding ( 2.2% ) . the recurrence rate was relatively low ( 2.2% ) during the long - term follow - up period ( 46.028.5 months ) despite the low r0 resection rate ( 25.0% ) and did not differ significantly from that of surgically resected gastric gist ( 5.0% ) . this comparable recurrence rate may be explained by the fact that most of the gastric gists in the endoscopic resection group had smaller sizes and low mitotic index counts ( < 5/high power field , 84.4% ) , which consequently corresponded to very low ( 50.0% ) and low ( 31.1% ) risk . indeed , if a gist is completely resected without residual tumor in an endoscopic view and is classified as lower risk by histopathological evaluation , the endoscopic procedure may be an alternative choice for optimal treatment of gist in the ugit , even with r1 resection margins . endoscopic resection of gastric gist is increasingly used for tissue diagnosis and treatment , and is expected to be a substitute for surgical resection in selected cases . endoscopic resection is a feasible and effective alternative therapeutic modality for lower risk gastric gist with acceptable long - term follow - up results .