Staging Laparoscopy in High-Risk Gastric Cancer: A Decade of Real-World Evidence and Therapeutic Impact from a Tertiary Referral Center

Background and Aims: Gastric cancer (GC) remains a leading cause of cancer-related mortality, frequently diagnosed at advanced stages. High-risk features-tumor size >= 40 mm, cT3/cT4, nodal involvement, diffuse histology, and Borrmann type III/IV-are associated with peritoneal metastasis (PM). Staging laparoscopy with peritoneal washing (PW) is superior to conventional preoperative imaging modalities, including contrast-enhanced CT, MRI, PET/CT and endoscopic ultrasound, in detecting occult peritoneal disease. In this era of personalized medicine and expanding loco-regional strategies such as cytoreductive surgery (CRS)/Hyperthermic IntraPEritoneal Chemotherapy (HIPEC) and Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC), accurate staging is crucial. This study assessed the impact of SL and PW in high-risk GC. Methods: We retrospectively analyzed 113 consecutive high-risk GC patients who underwent SL and PW between 2014 and 2024 at our institution. The primary endpoint was detection of PM or positive cytology (CY+). Secondary endpoints were treatment modification, eligibility for loco-regional therapy, and safety. Results: SL/PW identified PM or CY+ in 26 patients (23%), including 16 with CY+ only. None had radiologic signs of peritoneal disease. SL findings altered treatment in all cases: 21 patients (81%) with Peritoneal Cancer Index (PCI) < 6 underwent induction chemotherapy followed by CRS + HIPEC; 5 patients (PCI > 6) were spared non-therapeutic laparotomy and treated with bidirectional systemic chemotherapy and PIPAC. In 10 patients, systemic therapy was shifted from FLOT (fluorouracil, leucovorin, oxaliplatin, and docetaxel) to FOLFOX (fluorouracil, leucovorin, and oxaliplatin) +/- nivolumab. No perioperative complications occurred; all patients were discharged within 24 h without delay in systemic treatment. Conclusions: SL with PW is safe and significantly improves staging accuracy in high-risk GC, enabling personalized therapeutic planning. Routine integration of SL should be considered essential in treatment algorithms to guide systemic and loco-regional strategies.