This is a prospective study using a multicenter, randomized, controlled, open label, and efficacy validated approach.At present, there is no universally recognized optimal method for gastrointestinal reconstruction after proximal gastrectomy in the surgical treatment of gastric cancer.Author's team has proposed an innovative method named Hao's Esophagogastrostomay by Fisture Technique (HEFT).By adding anti reflux structures such as "false gastric fundus" and "false cardia" to the anastomosis of the residual stomach of the esophagus, not only can the purpose of anti reflux be achieved, but also the normal physiological channel can be maintained, it can fully utilize residual stomach function and reduce the difficulty of surgery.Through retrospective research, our single center has confirmed that HEFT is safe and feasible.On this basis, this study will compare the nutritional status, short- and medium- to long-term safety after laparoscopic HEFT and double-tract reconstruction , in order to evaluate and discover more reasonable digestive tract reconstruction methods after proximal gastrectomy, and to promote the development and popularization of minimally treatment technology for gastric cancer.

This study was jointly conducted by Shanghai-level hospitals (Huashan Hospital ,Shanghai Cancer Center, and Ruijin Hospital), with Huashan Hospital as the leading unit. This study will recruit 52 patients, with 26 patients in the experimental group and 26 patients in the control group. Using a central dynamic randomization method based on minimization, patients are assigned to groups in a 1:1 ratio. Based on the different anastomotic methods used in proximal gastrectomy, patients are divided into a HEFT group (experimental group) and a double-tract reconstruction group (control group).Plan to collect cases for 2 years, and follow up for another year after the last case is enrolled.

The primary endpoint of the study was the body weight loss (BWL) rate at 1 year after surgery. Secondary endpoints: Effect evaluation indicators: hemoglobin level at 1 year after surgery; Serum albumin level at 1 year after surgery; The incidence of anastomotic stenosis 1 year after surgery; Incidence of reflux esophagitis at 1 year after surgery. Evaluation of short-term surgical safety (duration: 7 days): operation time, intraoperative bleeding, anastomotic leakage, pancreatic leakage, and incidence of abdominal infection; Evaluation of medium- and long-term safety after surgery (duration: 36 months): overall survival rate at 3 years after surgery; disease-free survival rate at 3 years after surgery.

Inclusion Criteria:

1. 18 years old ≤ 80 years old;
2. The primary tumor lesion is located in the upper part of the stomach or the esophagogastric junction (Siewert II or III), and it is expected that R0 surgical results can be obtained by performing proximal gastrectomy and D2 dissection；
3. The primary lesion was diagnosed as adenocarcinoma through endoscopic biopsy and histopathological examination;
4. If it is upper gastric adenocarcinoma, the clinical TNM staging based on imaging needs to be cT1N0M0. If it is ductal gastric junction adenocarcinoma, it needs to be cT1-3N0-1M0, and clinical imaging judgment shows no distant gastric lymph node metastasis；
5. Expected survival exceeds 6 months;
6. No history of upper abdominal surgery (excluding laparoscopic cholecystectomy);
7. No chemotherapy, radiotherapy, targeted therapy, immunotherapy, etc. were performed before surgery;
8. Preoperative ECOG (Eastern Cooperative Oncology Group) physical status score 0/1;
9. Preoperative ASA (American Society of Anesthesiologists) grading I-III ;
10. Good function of important organs;
11. Sign the patient's informed consent form

Exclusion Criteria:

1. Preoperative imaging examination suggests the fusion of enlarged lymph nodes (maximum diameter ≥ 3cm) in the area;
2. Pregnant and lactating women;
3. Suffering from other malignant tumors within 5 years;
4. Preoperative body temperature ≥ 38 ℃ or complicated with infectious diseases requiring systematic treatment;
5. Serious mental illness;
6. Severe respiratory diseases, FEV1<50% of the expected value;
7. Severe liver and kidney dysfunction;
8. History of unstable angina or heart attack within 6 months;
9. History of cerebral infarction or cerebral hemorrhage within 6 months, excluding old intracavitary infarction;
10. Apply systemic corticosteroid therapy within one month;
11. Patients with complications of gastric cancer (bleeding, perforation, obstruction) requiring emergency surgery;
12. The patient has participated or is currently participating in other clinical studies (within 6 months)