A Clinical Study of Laparoscopic Proximal Gastrectomy Based on PTST(Parachute-tunnel- Style Technique) Esophagogastric Anastomose.

A Single-center, Prospective, Single-arm Clinical Study of Laparoscopic Proximal Gastrectomy Based on an Original Esophagogastric Anastomose (PTST,Parachute- Tunnel- Style Technique)

1. To evaluate the safety, simplicity and effectiveness of the gastric function (anti-reflux) preservation of the innovative "parachute-tunnel-style technique" (PTST) in laparoscopic proximal gastrectomy.
2. To investigate the correlation between anastomotic stenosis and blood supply of serosa-muscle flap,suture after esophagogastric anastomosis.(obtain objective indexes such as blood supply, healing pattern and length change of serosa-muscle flap through animal experiments)

Inclusion Criteria:

• Gastric cancer was confirmed histopathologically;
• Patients who may undergo proximal gastrectomy according to guidelines;
• Early upper gastric cancer, more than 1/2 of the distal gastric remnant remained after resection;
• Esophagogastric junction carcinoma with maximum diameter ≤4 cm;
• Patients with advanced upper gastric cancer (MSI-H) achieved cCR by neoadjuvant immunochemotherapy.

Exclusion Criteria:

• Patients with systemic conditions that cannot tolerate laparoscopic surgery;
• Distal gastric remnant was less than 1/2 after proximal gastrectomy.