​Hematological parameters as predictors of oral cancer prognosis: a systematic review and meta-analysis

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).

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.

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.

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.