Radical Surgery Versus Non-Surgery in Gastric Cancer Patients With Peritoneal Metastasis After Successful Conversion Therapy

The goal of this clinical trial is to learn if radical surgery improves prognosis andquality of life compared with continued standard non‐surgical treatment in gastric cancerpatients with peritoneal metastasis who have achieved successful conversion therapy. Themain questions it aims to answer are: ‐ Does radical surgery prolong overall survival in patients who achieve successfulconversion therapy? ‐ Does radical surgery provide better or at least comparable quality of life andsafety outcomes compared with continued standard treatment? Researchers will compareradical surgery versus continued standard systemic treatment to see whether radicalsurgery provides superior clinical benefit for patients after successful conversiontherapy.Participants will: ‐ Initial laparoscopic exploration confirms CY0P1 or CY1P1, absence of distant organmetastasis, a PCI ≤ 20, and presence or absence of ascites. ‐ Receive conversion therapy (chemotherapy, targeted/immunotherapy, intraperitonealtherapy, etc.) per standard guidelines, tailored to the patient's condition andmolecular‐pathological profile ‐ If clinical conversion is confirmed, undergo a second laparoscopic exploration toverify successful conversion ‐ If successful conversion is confirmed (peritoneal lesions cleared or markedlyregressed with negative biopsy, no ascites or distant metastases, R0‐resectableprimary tumor, and improved patient condition), be randomized 1:1 to either thesurgery group or the standard treatment group ‐ In the surgery group, undergo curative gastrectomy with D2 lymphadenectomy duringthe second laparoscopy, followed by adjuvant therapy and maintenance treatment ‐ In the standard treatment group, continue systemic therapy without surgery, withmaintenance 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 medicalresource use outcomes