Abstract
OBJECTIVE: This systematic review and meta-analysis aimed to assess the prognostic value of pre-treatment hematological parameters, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and mean platelet volume (MPV), in patients with oral squamous cell carcinoma (OSCC). METHODS: A systematic search of PubMed, Embase, Scopus, Web of Science, ScienceDirect, and Google Scholar was conducted until April 2025. We included English-language observational studies reporting associations between NLR, PLR, MPV, and survival or clinicopathological outcomes in OSCC. Data extraction and risk of bias assessment using the Newcastle-Ottawa Scale were performed independently by two reviewers. Hazard ratios (HRs) and odds ratios (ORs) were pooled using a random-effects model. The certainty of evidence was evaluated using the GRADE. RESULTS: Thirty-five studies (approximately 7940 patients) were included. A high NLR was associated with worse overall survival (pooled HR 1.59, 95% CI 1.32-1.92) and disease-free survival (HR 1.66, 95% CI 1.31-2.10). PLR showed similar associations with overall survival (HR 1.58, 95% CI 1.29-1.94) and disease-free survival (HR 1.50, 95% CI 1.18-1.90). Between-study heterogeneity was moderate to high in this study. MPV findings were inconsistent and not pooled. CONCLUSIONS: Elevated NLR and PLR correlate with poorer outcomes in OSCC, with effect sizes varying by study design and cut-off selection. These blood-based indices may aid in risk stratification; however, prospective validation with standardized thresholds is required.