Systematic Review of Neutrophil-to-Lymphocyte Ratio as a Prognostic Marker in Oral Cancer

Abstract

Background: Oral squamous cell carcinoma (OSCC) remains a major global health concern with suboptimal survival outcomes despite advancements in treatment modalities. Recently, systemic inflammatory biomarkers such as the neutrophil-to-lymphocyte ratio (NLR) have gained attention for their prognostic significance. Objective: This systematic review aims to evaluate the prognostic value of NLR in oral cancer, particularly OSCC, and to synthesize evidence regarding its association with survival outcomes and clinicopathological features. Methods: A systematic literature search was conducted in PubMed, Scopus, and Web of Science databases for studies published between 2010 and 2025. Studies evaluating NLR in OSCC patients with reported survival outcomes were included. Data were analyzed qualitatively. Results: A total of 35 studies involving approximately 7,500–8,000 patients were included. Elevated pre-treatment NLR was consistently associated with poor overall survival (OS), disease-free survival (DFS), advanced tumor stage, and lymph node metastasis. Meta-analytic evidence demonstrated a significant increase in mortality risk (HR ≈ 1.5– 1.8) in patients with high NLR. Conclusion: NLR is a reliable, cost-effective, and noninvasive prognostic biomarker in oral cancer. Standardization of cutoff values and integration with other biomarkers may enhance its clinical applicability.