A Prospective, Multicenter, Phase III Randomized Controlled Trial Evaluating the Impact of Radical Surgery Versus Non-Surgery on Prognosis and Quality of Life in Gastric Cancer Patients With Peritoneal Metastasis After Successful Conversion Therapy (ALANO Study, CGCA2603 Study)
The goal of this clinical trial is to learn if radical surgery improves prognosis and quality of life compared with continued standard non-surgical treatment in gastric cancer patients with peritoneal metastasis who have achieved successful conversion therapy. The main questions it aims to answer are: * Does radical surgery prolong overall survival in patients who achieve successful conversion therapy? * Does radical surgery provide better or at least comparable quality of life and safety outcomes compared with continued standard treatment? Researchers will compare radical surgery versus continued standard systemic treatment to see whether radical surgery provides superior clinical benefit for patients after successful conversion therapy. Participants will: * Initial laparoscopic exploration confirms CY0P1 or CY1P1, absence of distant organ metastasis, a PCI ≤ 20, and presence or absence of ascites. * Receive conversion therapy (chemotherapy, targeted/immunotherapy, intraperitoneal therapy, etc.) per standard guidelines, tailored to the patient's condition and molecular-pathological profile * If clinical conversion is confirmed, undergo a second laparoscopic exploration to verify successful conversion * If successful conversion is confirmed (peritoneal lesions cleared or markedly regressed with negative biopsy, no ascites or distant metastases, R0-resectable primary tumor, and improved patient condition), be randomized 1:1 to either the surgery group or the standard treatment group * In the surgery group, undergo curative gastrectomy with D2 lymphadenectomy during the second laparoscopy, followed by adjuvant therapy and maintenance treatment * In the standard treatment group, continue systemic therapy without surgery, with maintenance treatment and salvage surgery permitted if clinically indicated * Complete quality of life questionnaires at predefined time points * Be followed up for survival, disease progression, adverse events and medical resource use outcomes
• Patients voluntarily participate in the study, sign the informed consent form, and demonstrate good compliance.
• Age ≥ 18 years and ≤ 70 years.
• Histologically and/or cytologically confirmed gastric cancer.
• No evidence of gastric outlet obstruction or intestinal obstruction.
• No distant metastasis on imaging examination. Initial laparoscopic exploration confirms CY0P1 or CY1P1, without distant organ metastasis, with a recorded peritoneal carcinomatosis index (PCI) ≤ 20, and with either positive or negative ascites. Patients meeting these criteria are eligible for pre-enrollment. Following successful conversion therapy, a second laparoscopic exploration must confirm conversion to CY0P0, with no distant organ metastases and no regional lymph node metastases beyond the second station. Only upon meeting these criteria are patients formally enrolled in the study.
• No prior chemotherapy, targeted therapy, or immunotherapy.
• ECOG performance status score of 0-2.
• Life expectancy ≥ 12 weeks.
• Laboratory requirements: Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L, platelet count ≥ 75 × 10⁹/L, hemoglobin ≥ 8 g/dL; Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 2.5 × upper limit of normal (ULN); total bilirubin ≤ 1.5 × ULN. In the presence of liver metastases, AST and ALT ≤ 5 × ULN; Serum creatinine (Cr) ≤ 1.5 × ULN, or creatinine clearance (CCr) ≥ 60 mL/min; International normalized ratio (INR) ≤ 1.5 × ULN; prothrombin time (PT) and activated partial thromboplastin time (APTT) ≤ 1.5 × ULN.