Short-term safety and feasibility of laparoscopic-endoscopic cooperative surgery for gastric subepithelial tumors: a retrospective observational study of the first single-center experience in Mongolia.

Purpose: Laparoscopic-endoscopic cooperative surgery (LECS) is a minimally invasive, organ-preserving approach for gastric subepithelial tumors (SETs). Although well established in high-volume East Asian centers, its use in Mongolia has not been reported. We report on our first experience and assess short-term safety and feasibility. Methods: We retrospectively reviewed consecutive patients who underwent LECS for gastric SETs at the National Cancer Center of Mongolia (November 2022-May 2025). Clinicopathologic characteristics, operative outcomes, and postoperative events were analyzed; complications were graded by the Clavien-Dindo classification. Results: Thirty-five patients underwent LECS during the study period. The mean age was 55 ± 12 years, and 60% were female. The mean tumor size was 27 ± 11 mm, and most tumors originated from the fourth endoscopic ultrasonography layer (muscularis propria). Histopathological analysis revealed that gastrointestinal stromal tumors accounted for 65.7% of all resected lesions. The mean operative time was 118 ± 57 minutes, and the mean blood loss was 44 ± 20 mL. All procedures were completed laparoscopically with R0 resection and no conversion to open surgery. No postoperative complications of Clavien-Dindo grade ≥II occurred. The mean postoperative hospital stay was 5.9 ± 0.9 days, and no reoperation, readmission, or recurrence was observed during a mean follow-up of 17.8 ± 7.2 months. Conclusion: LECS was safely introduced in Mongolia, achieving excellent perioperative outcomes and complete resection. These findings support LECS as a feasible, function-preserving option for appropriately selected gastric SETs.