A Clinical Study Evaluating the Efficacy of Systemic Chemotherapy and Immune Checkpoint Inhibitors Combined With Hyperthermic Intraperitoneal Chemotherapy in the Treatment of Gastric Cancer Patients With Peritoneal Metastasis

This study tests whether adding heated chemotherapy directly into the abdomen (called HIPEC) during surgery, combined with systemic chemotherapy and immunotherapy, improves outcomes for patients with gastric (stomach) cancer that has spread to the lining of the abdominal cavity (peritoneal metastasis). **You may be eligible if...** - You are 18–75 years old - You have been diagnosed with stomach cancer that has spread to the peritoneum (abdominal lining), confirmed by laparoscopy - The spread is limited (peritoneal cancer index of 12 or less) - You have not yet received chemotherapy, radiation, or targeted therapy - You are physically functional (ECOG 0–1) - Your blood counts and organ function are in an adequate range **You may NOT be eligible if...** - You have another active cancer from the past 5 years - You have an active autoimmune disease - You are allergic to any of the study medications - You have epilepsy or significant mental health conditions - You are pregnant or breastfeeding - You have cancer that has spread beyond the peritoneum to other distant sites Talk to your doctor to see if this trial is right for you.