Blood-based biomarkers in gastric cancer peritoneal metastases: current evidence and potential clinical applications

Gastric cancer remains among the most common malignancies. Peritoneal metastases account for a significant share of mortality in gastric cancer; however, early detection is constrained by the limited sensitivity of current diagnostic approaches. Computed tomography represents the primary imaging modality for initial assessment, whereas staging laparoscopy, combined with peritoneal cytology and/or biopsy, plays a crucial role in detecting occult peritoneal metastases and confirming the diagnosis. The extent of peritoneal disease, the feasibility of complete cytoreduction, and the postoperative quality of life remain the primary requirements for deciding surgical intervention. As clinical staging and management remain challenging, non-invasive diagnostic and prognostic biomarkers are needed to improve risk stratification and optimize therapeutic strategies. This review summarizes the blood biomarkers reported during the last 5 years and their potential role in predicting peritoneal metastases. A literature search was conducted in PubMed on 12 March 2026, covering publications from March 2021 to March 2026. Ten eligible original studies were included. Although blood-based biomarkers show promise for improving the detection and management of peritoneal metastases in gastric cancer, the available evidence remains limited and heterogeneous. Further prospective, multicenter studies with external validation are required to establish their clinical utility before their integration into routine practice.