Safety of Laparoscopic Resection for Gastrointestinal Stromal Tumor on Unfavorable Anatomic Site of Stomach

Inclusion Criteria:

* Age from over 18 to under 75 years;
* Gastrointestinal stromal tumor at unfavorable anatomic sites of stomach preoperatively confirmed by endoscopy, ultrasound endoscopy, CT or MRI;
* Diameter of tumor size is ≥2cm and ≤5cm confirmed by contrast CT or MRI;
* Patients whose tumor is resectable by laparoscopic technique at preoperative assessment;
* No evidence of distant metastasis and tumor invading nearby organs at preoperative assessment;
* Performance status of 0 or 1 on ECOG (Eastern Cooperative Oncology Group) scale;
* ASA (American Society of Anesthesiology) score I, II, or III;
* Written informed consent.

Exclusion Criteria:

* Women during pregnancy or breast-feeding;
* Severe mental disorder;
* History of previous upper abdominal surgery (except laparoscopic cholecystectomy);
* History of other malignant disease within the past five years;
* History of previous neoadjuvant imatinib therapy;
* History of unstable angina or myocardial infarction within the past six months;
* History of cerebrovascular accident within the past six months;
* History of continuous systematic administration of corticosteroids within the past month;
* Requirement of simultaneous surgery for other disease;
* Emergency surgery due to complication (bleeding, obstruction or perforation) caused by gastrointestinal stromal tumor;
* FEV1\<50% of predicted value;
* Patients with GIST locates at favorable anatomic sites detected by contrast CT, MRI or ultrasound endoscopy at preoperative assessment;
* Patients with GIST diameter\<2cm or\>5cm detected by contrast CT or MRI;
* Presence of distant metastasis or tumor invading nearby organs at preoperative assessment.

Withdrawal Criteria:

* Patients postoperatively confirmed as non-GIST case by pathology (These cases are enrolled in safe group for future statistic analysis);
* GIST at unfavorable anatomic site diagnosed before operation, while GIST at favorable anatomic site determined by intraoperative exploration;
* Patients confirmed as tumor rupture , metastasis or invading nearby organs intraoperately;
* Patients requiring simultaneous surgical treatment of other diseases;
* Sudden severe complications during the perioperative period (intolerable surgery or anesthesia), which renders it unsuitable or unfeasible to implement the study treatment protocol as scheduled;
* Patients confirmed to require emergency surgery by attending physicians due to changes in the patient's condition after inclusion in this study;
* Patients who voluntarily quit or discontinue treatment for personal reasons at any stage after inclusion in this study;
* Treatment implemented is proven to violate study protocol.