Feasibility and Safety of Laparoscopic Purse-string Suture Clamp and Multi-functional Seal Cap for Totally Laparoscopic Radical Total Gastrectomy

Inclusion Criteria: * Age 18-80 years, regardless of gender; Histologically confirmed gastric or gastroesophageal junction (GEJ) adenocarcinoma. For GEJ cancer, only Siewert type III and type II (without requiring thoracotomy) are eligible (applicable to multiple primary cancers); Preoperative assessment by a gastrointestinal surgeon and imaging specialist confirming cStage I-III disease with eligibility for curative-intent R0 resection. Patient consents to surgery and is deemed surgically fit by the surgeon; Anticipated R0 resection achievable via total gastrectomy with D1+/D2 lymphadenectomy; Expected survival ≥6 months; ECOG Performance Status (PS) score (see Appendix 2) of 0 or 1; Adequate major organ function; Body weight ≥40 kg or BMI \>18.5 and \<30 kg/m²; No prior chemotherapy, radiotherapy, targeted therapy, or immunotherapy; Patient has read and fully understood the informed consent form and voluntarily signed it Exclusion Criteria: * History of other active malignancies within the past 5 years or concurrent malignancies (except cured localized tumors such as basal cell carcinoma, squamous cell carcinoma of the skin, superficial bladder cancer, carcinoma in situ of the prostate/cervix/breast, Stage I lung/colorectal cancer, etc.). Previous upper abdominal surgery (excluding laparoscopic cholecystectomy). History of gastrectomy, endoscopic mucosal resection (EMR), or endoscopic submucosal dissection (ESD). Requirement for concurrent surgery for other diseases. Emergency surgery due to gastric cancer complications (bleeding, obstruction, or perforation). Planned or prior organ/bone marrow transplantation. Blood transfusion within 2 weeks before surgery, bleeding history, or Grade ≥3 hemorrhage (CTCAE v4.0) within 4 weeks. Coagulopathy (INR \>1.5 without anticoagulants) or use of anticoagulants (warfarin/heparin). Prophylactic low-dose warfarin (≤1 mg/day) or aspirin (≤100 mg/day) is permitted if INR ≤1.5. Arterial/venous thrombosis within 6 months (e.g., stroke, DVT, pulmonary embolism), excluding catheter-related thrombosis from prior chemotherapy. Myocardial infarction within 6 months or uncontrolled arrhythmia (QTc ≥450 ms \[men\]/≥470 ms \[women\] by Fridericia's formula). NYHA Class III-IV heart failure or LVEF \<50%. Ventilatory dysfunction (FEV1 \<50% predicted). Urinary protein ≥++ or 24-hour urine protein \>1.0 g. Clinically significant pleural/peritoneal effusion requiring intervention. HIV infection. Active tuberculosis. Non-healing wounds or incomplete fracture healing. Active/suspected autoimmune disease (stable cases without immunosuppressants allowed). Severe autoimmune diseases (e.g., SLE, IBD), chronic diarrhea disorders, or active HBV/HCV (HBV DNA \<500 copies/mL permitted). Systemic corticosteroids (\>10 mg/day prednisone equivalent) within 14 days (topical/inhaled steroids or physiologic replacement doses allowed). Active infection requiring systemic antibiotics within 14 days (prophylactic antibiotics permitted). Live vaccines within 28 days (inactivated flu vaccines allowed). Concurrent participation in another surgical trial. Alcohol/drug abuse history (abstinent patients eligible). Non-compliance or incomplete data affecting safety/efficacy assessments. Pregnancy/lactation. Other conditions deemed high-risk by investigators. Investigator-determined ineligibility.