The efficacy of three different reconstruction methods after proximal gastrectomy will be investigated in this study through a prospective, multicenter, randomized controlled trial.

In the trial, 180 patients with proximal early gastric cancer will be enrolled and then randomly assigned to one of three groups: Group A (Kamikawa, n = 60), Group B (single-tract jejunal interposition, n = 60), or Group C (SOFY reconstruction, n = 60). The general information, past medical history, laboratory and imaging findings, and surgical procedures of each patient will be recorded. Patients in Group A, Group B and Group C will receive Kamikaze reconstruction, single-tract jejunal interposition reconstruction and SOFY reconstruction respectively after standard proximal gastrectomy and lymph nodes dissection. The primary endpoint will be the incidence of reflux esophagitis, while the incidence of anastomotic leakage, anastomotic stenosis, operative time, and intraoperative blood loss will be secondary endpoints to compare the efficacy of these three reconstruction methods after proximal gastrectomy.

Inclusion Criteria:

• Age between 20-75 years old, male or female;
• Pathological diagnosis of preoperative endoscopic biopsy: the tumor is located in the upper 1/3 of the stomach (including the esophagogastric junction), and the clinical staging of gastric cancer： Ia and Ib (T1N0M0, T1N1M0, and T2N0M0) (14) according to the eighth edition of the AJCC (15);
• No distant metastasis observed on preoperative chest radiograph, abdominal ultrasound or upper abdominal CT;
• ASA grade 1-3;
• Patients without contraindications to surgery;
• Patients and their families voluntarily signing the informed consent form and participating in the study;

Exclusion Criteria:

• Patients diagnosed with primary tumors or distant metastasis;
• Patients whose tumor is located in the greater curvature side of the stomach;
• Patients with coagulation dysfunction which could not be corrected;
• Patients who were diagnosed with viral hepatitis and cirrhosis;
• Patients who were diagnosed with diabetes mellitus, uncontrolled or controlled with insulin;
• Patients with organ failure such as heart, lung, liver, brain, kidney failure;
• Patients with ascites or cachexia preoperatively in poor general conditions;
• Patients diagnosed with immunodeficiency, immunosuppression or autoimmune diseases (such as allogeneic bone marrow transplant, immunosuppressive drugs, SLE, etc.).
• Patients refusing to sign the informed consent of the study;