Rationale for standardized staging laparoscopy before neoadjuvant therapy in locally advanced gastric cancer

Peritoneal metastasis (PM) is a dominant mode of failure in gastric and gastroesophageal junction adenocarcinoma and is associated with poor survival, particularly when radiographically occult at diagnosis. Cross-sectional imaging has limited sensitivity for low-volume peritoneal disease, and a clinically relevant proportion of patients with apparently non-metastatic, locally advanced tumours on computed tomography harbor macroscopic PM or positive peritoneal cytology, both classified as stage IV disease. International guidelines therefore recommend staging laparoscopy (SL) with peritoneal washings in patients with potentially resectable, locally advanced tumours prior to neoadjuvant systemic therapy or curative-intent gastrectomy. Nevertheless, real-world implementation remains inconsistent, while contemporary series report upstaging rates of approximately 20-40% among guideline-eligible patients. This narrative review summarizes current evidence regarding the diagnostic yield and limitations of SL, clinicopathologic predictors of occult peritoneal dissemination, and the downstream consequences of omitting peritoneal staging. Failure to perform SL may result in inaccurate stage assignment, delayed initiation of stage-appropriate systemic therapy, and exposure to non-beneficial gastrectomy in patients with occult peritoneal stage IV disease. The implications for biomarker-driven treatment strategies, regional approaches targeting peritoneal disease, and clinical trial eligibility are also discussed. Finally, a pragmatic framework for integrating SL into routine multidisciplinary care pathways is proposed.