Su1249 ENDOSCOPIC RESECTION FOR SMALL SUBMUCOSAL TUMORS ORIGINATING FROM THE MUSCULARIS PROPRIA LAYER IN THE GASTRIC FUNDUS

Gastric small submucosal tumors (SMTs), particularly gastrointestinal stromal tumors (GISTs) with malignant potential, is becoming increasingly common. Meanwhile, fundus of stomach is regarded as a difficult area for endoscopic resection (ER). In this study, we investigated the necessity and feasibility of ER for small SMTs of the gastric fundus in a large series of patients which were lacked before, and examined its safety and long-term outcomes. 537 consecutive patients with SMTs no more than 20mm of the gastric fundus originating from the muscularis propria (MP) layer and treated with endoscopic submucosal excavation (ESE) or endoscopic full-thickness resection (EFTR) were included in this retrospective study at Zhongshan Hospital of Fudan University from January 2013 to September 2016. Clinicopathological, endoscopic and follow-up data were collected and analyzed. There were 332 (61.8%) GISTs among all small SMTs. Based on statistical analysis, tumors with greater size, near cardia and treated by EFTR were the significant contributors to long operative times. Although total rate of complications was 9.3%, few serious adverse events occurred in three (0.6%) patients including major pneumoperitoneum, major hydrothorax and bleeding. Unlike lager tumor size and longer procedure time, endoscopist experience had positive impact on decreasing complications. The en bloc resection was achieved in 100% of patients and complete resection was achieved for 530(98.7%) lesions. A median follow-up of 32 months was available and all patients were free from local recurrence or distant metastasis during the study period. It is necessary to remove small gastric SMTs by ER because GISTs with malignant potential account for majority. Although technological difficulties present in fundus of stomach, ER is quite safe for resection of small gastric SMTs. Tumor size, procedure time and the experience of endoscopists will influence the development of ER-related adverse events.Tabled 1Table 1 Clinicpathological characteristics of 537 gastric fundus SMTs treated by ERPatientsAge, mean (median, range), year56.6±10.3 (58, 21-82)Sex, Male/Female170/367LesionsSize, mean (median, range), mm10.0±4.6 (10, 2-20)＜10mm252 (46.9%)10 mm-20mm285 (53.1%)Location (near cardia)Yes178 (33.1%)No359 (66.9%)Extraluminal growthNo473 (88.1%)Yes64 (11.9%)HistopathologyGIST332 (61.8%)Leiomyoma196 (36.5%)Clarifying fibrous tumors8 (1.5%)Schwannoma1 (0.2%)TechniqueSurgical approachESE322 (60.0%)EFTR215 (40.0%)Procedure time, mean (median, range), min38.3±21.8 (34, 10-210)＜45min347 (69.6%)≥45min163 (30.4%)Endoscopist experience＜25 ERs/y211 (39.3%)≥25 ERs/y326 (60.7%)En bloc resection537 (100%)Complete resection530 (98.7%)Complications50 (9.3%)Pneumoperitoneum20 (3.7%)Minor pneumoperitoneum19 (3.5%)Major pneumoperitoneum1 (0.2%)Hydrothorax13 (2.4%)Minor hydrothorax12 (2.2%)Major hydrothorax1 (0.2%)PEECS16 (3.0%)Major bleeding1 (0.2%)Recurrence0 (0%)Metastasis0 (0%) Open table in a new tab Tabled 1Table 2 Multivariate analysis of research cohortFactorsProcedure time ≥45minAdverse events of EROR95% CIP valueOR95% CIP valueAge< 60 years11≥60 years1.2260.821-1.8310.3200.6780.327-1.4080.298SexMale11Female1.3850.900-2.1330.1390.5660.279-1.1490.115Tumor size<10mm1110-20mm1.8651.249-2.7850.0022.3271.071-5.0550.033Near cardiaNo11Yes1.5511.016-2.3660.0421.6770.713-3.9440.236Extraluminal growthNo11Yes1.7260.970-3.0700.0632.0030.892-4.4970.092HistopathologyGIST11Others0.7170.445-1.1570.1731.1560.472-2.8350.751Surgical approachESE11EFTR2.8931.932-4.331<0.0011.3900.659-2.9310.387Endoscopist experience11≥25ERs/y1.3550.903-2.0340.1430.3500.157-0.7770.010Procedure time<45min1≥45min3.3751.153-4.8930.019 Open table in a new tab