The third space robotic and endoscopic cooperative surgery (TS-RECS) combines the endoscopic techniques and the merits of Da Vinci surgical robot, such as flexible and precise instruments, tremors filtering system and a 3-D surgical view. TS-RECS takes full advantage of the methodology of the third space, making it possible to dissect gastric GISTs (gastrointestinal stromal tumors) entirely without the damage of mucosal layer. Here, this study preliminarily assessed the feasibility, safety and effectivity of the novel hybrid operation.

Inclusion Criteria:

• Patients with gastric GISTs originating from muscularis propria diagnosed by EUS (endoscopic ultrasound)；
• The maximal cross-sectional diameter of tumor ranging from 2cm to 5cm, or the maximal cross-sectional diameter of tumor <2cm but with malignant potential ( irregular shape, cystic space, heterogeneity and rapid growth during follow-ups ) ；
• No evidence of tumor metastasis on all per-operative evaluations；

Exclusion Criteria:

• 1. Patients with serious systemic comorbidities, such as severe heart failure, respiratory failure, uncontrolled hypertension;
• 2. Patients with advanced malignant tumor;
• 3. Patients were required the emergency operation by complete intestinal obstruction, perforation and hemorrhage caused by the tumor;
• 4.Patients with ulcer penetration into tumors;
• 5. Patients with the contraindications for general anesthesia;
• 6. Patients were pregnant or younger than 18 years old；