Gastric cancer ranks as the fifth most common malignancy worldwide and the fourth leading cause of cancer-related deaths. In China, its incidence and mortality rank third among all cancers. While the global incidence of gastric cancer is declining, proximal gastric cancer and adenocarcinoma of the esophagogastric junction (AEG) are on the rise. Due to the unique characteristics of AEG, there is no standardized treatment consensus, making the selection of an optimal surgical approach and reconstruction method crucial for improving patient outcomes.

For early-stage proximal gastric cancer and AEG, total gastrectomy (TG) and proximal gastrectomy (PG) are common surgical options. PG, increasingly favored for its function-preserving benefits, has been shown to be a safe and effective alternative to TG. While TG effectively removes lymph nodes and reduces reflux risk, it leads to permanent loss of gastric function and nutritional deficiencies. PG better preserves gastrointestinal function but is limited by the risk of reflux esophagitis, highlighting the need for improved reconstruction techniques.

Several reconstruction methods exist after PG, including esophagogastric anastomosis, jejunal interposition, double-tract reconstruction (DTR), double-flap technique (DFT), and tubular gastric anastomosis, each with varying efficacy in preventing reflux. Studies suggest that DTR reduces reflux and improves quality of life compared to esophagogastric anastomosis, while DFT, first introduced in 1998, has gained popularity for its advantages in maintaining nutrition and minimizing reflux. Additionally, tubular gastric anastomosis, which constructs a narrow gastric tube to facilitate tension-free anastomosis, has shown potential benefits for AEG patients.

Most existing studies on laparoscopic or robot-assisted reconstruction techniques for proximal gastric cancer are retrospective, lacking high-quality prospective evidence. Furthermore, comparative data on their anti-reflux efficacy and postoperative quality of life remains l

Gastric cancer is the fifth most common malignant tumor worldwide and ranks fourth in cancer-related mortality. In China, the incidence and mortality rate of gastric cancer rank third among all malignancies. While the global incidence of gastric cancer has been steadily declining, the incidence of proximal gastric cancer has been rising. Additionally, the incidence of adenocarcinoma of the esophagogastric junction (AEG) has been increasing annually, showing an upward trend worldwide. Due to its unique anatomical location and significant tumor biological heterogeneity, there is no standardized consensus on the optimal treatment for AEG. Therefore, selecting an appropriate surgical resection and reconstruction approach remains crucial for improving the prognosis of patients with proximal gastric cancer and AEG.

For early-stage proximal gastric cancer and AEG, either total gastrectomy (TG) or proximal gastrectomy (PG) can be performed. With the advancement of function-preserving surgical concepts, PG has been increasingly recognized as a viable option. The Japanese Clinical Oncology Group (JCOG1401) trial demonstrated that laparoscopic proximal gastrectomy (LPG) is a safe and effective treatment for early-stage proximal gastric cancer compared to laparoscopic total gastrectomy (LTG). However, patients undergoing TG often experience long-term postoperative quality-of-life concerns. Although TG can effectively remove lymph nodes and reduce the risk of gastroesophageal reflux, it results in the permanent loss of gastric storage, mechanical grinding, and secretory functions, as well as reduced feasibility of postoperative endoscopic examination. TG patients may also suffer from nutritional deficiencies, including vitamin B12 deficiency, iron deficiency, weight loss, anemia, diarrhea, and dumping syndrome. In contrast, PG offers advantages in preserving gastrointestinal function and nutritional status. However, its widespread adoption is limited by the risk of reflux esophagitis. Thus, selecting an optimal reconstruct

Inclusion Criteria:

• Age from over 18 to under 75 years.
• Preoperative gastroscopic pathological biopsy was performed, and histologically confirmed as carcinoma (papillary adenocarcinoma, tubular adenocarcinoma, mucinous adenocarcinoma, signet ring cell carcinoma, poorly differentiated adenocarcinoma, mixed adenocarcinoma, etc.) or adenoma.
• Diagnosed with upper gastric cancer (T1N0M0, T1N1M0, or T2N0M0) or esophagogastric junction cancer with a diameter ≤4 cm based on the 8th edition of the AJCC staging system, as confirmed by CT, MRI, endoscopic ultrasound, and pathology.
• Undergoing proximal gastrectomy with D2 lymphadenectomy is expected to achieve curative resection, with the remaining gastric volume required to be at least half of the pre-resection volume.
• Performance status of 0 or 1 on ECOG (Eastern Cooperative Oncology Group) scale.
• ASA (American Society of Anesthesiology) class I to III.
• The patient has adequate organ function and is capable of tolerating surgery.
• Written informed consent.

Exclusion Criteria:

• Patients who have received preoperative radiotherapy, chemotherapy, targeted therapy, or immunotherapy.
• Presence of multiple malignant tumors in the stomach.
• History of upper abdominal surgery, except for laparoscopic cholecystectomy.
• History of gastric surgery, except for endoscopic submucosal dissection (ESD) or endoscopic mucosal resection (EMR) for gastric cancer.
• Evidence of distant metastasis diagnosed by thoracoabdominal CT/MRI or PET-CT.
• Pregnant or lactating women.
• History of uncontrolled epilepsy, central nervous system disorders, or psychiatric illness.
• Patients with limb disabilities or motor function impairment.
• History of other malignant diseases within the past five years, except for cured skin cancer and cervical carcinoma in situ.
• Clinically severe (i.e., active) heart disease, such as symptomatic coronary artery disease, New York Heart Association (NYHA) class II or higher congestive heart failure, severe arrhythmia requiring medical intervention, or myocardial infarction within the past six months.
• History of stroke or cerebral hemorrhage within the past six months.
• Severe, uncontrolled recurrent infections or other serious uncontrolled comorbidities.
• Pulmonary function test showing FEV1 < 50% of the predicted value.
• Patients requiring emergency surgery due to tumor-related complications (e.g., bleeding, perforation, or obstruction).

Patients with upper gastric cancer (T1N0M0, T1N1M0, or T2N0M0 according to the AJCC 8th edition) and esophageal junction cancer (≤4cm in diameter).