Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Melanoma: A Systematic Review and Meta-Analysis

The neutrophil-to-lymphocyte ratio (NLR) has emerged as a potential prognostic biomarker in melanoma, yet its clinical validity remains incompletely characterized. This study aimed to thoroughly assess the relationship between NLR and clinical outcomes in melanoma patients. We performed a comprehensive literature search in Embase, PubMed, the Cochrane Library, and Web of Science from inception until August 14, 2024. Studies evaluating NLR's prognostic value in melanoma were eligible for inclusion. Primary endpoints were overall survival (OS) and progression-free survival (PFS). Hazard ratios (HRs) with 95% confidence intervals (CIs) were extracted from both univariate and multivariate analyses and pooled using random-effects models. Sensitivity and subgroup analyses were performed to identify potential confounders. All analyses were conducted using Review Manager 5.4.1 and Stata 15.1. Thirty-seven articles met inclusion criteria. Meta-analysis demonstrated that elevated NLR notably correlated with inferior OS (HR = 1.89, 95% CI: 1.68-2.12; p < 0.00001) and shortened PFS (HR = 1.76, 95% CI: 1.49-2.07; p < 0.00001). Subgroup analyses confirmed the consistent association between elevated NLR and adverse outcomes across different treatment modalities, sample sizes, and NLR cut-off values. This meta-analysis establishes elevated NLR as an independent predictor of poor survival outcomes in melanoma patients. These findings support the incorporation of NLR as a cost-effective prognostic biomarker in clinical practice, potentially facilitating risk stratification and treatment optimization.