Lenvatinib in Combination With Nivolumab Plus Chemotherapy in Metastatic Gastric Cancer Patients With Malignant Ascites

This study is testing a combination of targeted therapy (lenvatinib), immunotherapy (nivolumab), and standard chemotherapy in patients with advanced gastric (stomach) or gastroesophageal junction cancer that has spread to the lining of the abdomen (peritoneal metastasis) with fluid buildup (malignant ascites). **You may be eligible if...** - You are older than 19 years - You have been newly diagnosed with metastatic, unresectable, or recurrent gastric/GEJ adenocarcinoma - Your cancer has spread to the peritoneum (abdominal lining) with significant fluid buildup (grade 2 or higher ascites confirmed by CT scan) - Your tumor tests positive for PD-L1 (CPS ≥5), a marker that indicates immunotherapy may be effective - You are in good enough physical condition (ECOG performance status assessed by your doctor) **You may NOT be eligible if...** - Your cancer does not have peritoneal metastasis or high enough PD-L1 expression - You have significant organ dysfunction or other conditions making this combination unsafe Talk to your doctor to see if this trial is right for you.