Prognostic Significance of Platelet-to-Lymphocyte Ratio in Patients With Triple-negative Breast Cancer: Systematic Review and Meta-Analysis.
BACKGROUND/AIM: The platelet-to-lymphocyte ratio (PLR), a systemic inflammatory biomarker, has been linked to treatment response in breast cancer (BC). However, its prognostic value in triple-negative breast cancer (TNBC) remains unclear. This meta-analysis evaluated the association between PLR and survival outcomes in patients with TNBC. MATERIALS AND METHODS: This study was registered on PROSPERO in January 2024 under protocol number CRD42024506786. Databases searched were PubMed, Embase and Cochrane Library in December 2024. Hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled to evaluate the association between PLR and overall (OS), progression-free (PFS), and disease-free (DFS) survival. Heterogeneity was assessed using I2 statistics. RESULTS: Six studies with 819 patients with TNBC were included. PLR cut-off values were reported in five studies, determined either from previous research or receiver operating characteristic curves. A high PLR was not significantly associated with OS (HR=1.35, 95% CI=0.99-1.84; p=0.06; I2=43%). However, after excluding a high-risk bias study, high PLR was associated with reduced OS (HR=1.55, 95% CI=1.21-2.00; p=0.006; I2=0%). PLR was not significantly associated with PFS (HR=1.73, 95% CI=0.69-4.33; p=0.24; I2=79%) but was significantly associated with lower DFS (HR=1.69, 95% CI=1.25-2.28; p=0.0006; I2=0%). CONCLUSION: While PLR was not significantly associated with OS or PFS, it correlated with DFS in TNBC: These findings suggest that PLR may have prognostic value, but further large-scale studies are needed to establish its clinical utility and optimal cut-off values.