Clinical Significance of Neutrophil-to-Lymphocyte Ratio and Lymphocyte-to-Monocyte Ratio in Oral Squamous Cell Carcinoma

Background/Objectives: Oral squamous cell carcinoma (OSCC) remains a significant global health concern, characterized by high morbidity and mortality, particularly in advanced stages. Increasing evidence suggests that systemic inflammation plays a critical role in tumor progression and patient outcomes. This retrospective cohort study aimed to evaluate the prognostic value of systemic inflammatory markers—specifically the neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR)—in correlation with histopathological parameters in patients with OSCC. Methods: A total of 157 patients diagnosed with histopathologically confirmed OSCC between January 2019 and December 2024 were included. Clinical, laboratory, and histopathological data were analyzed, including lymphovascular and neural invasion and worst pattern of invasion (WPOI). Statistical analyses, including ROC curve analysis, Kaplan–Meier survival analysis, and Cox regression, were performed to determine the prognostic significance of NLR and LMR. Results: The cohort demonstrated a predominance of male patients (81.5%), with the highest incidence observed in the 61–70 age group. WPOI showed a statistically significant association with survival outcomes (p = 0.003), with type 5 invasion correlating with increased mortality. ROC analysis identified optimal cutoff values of 2.88 for NLR and 1.87 for LMR. Elevated NLR and decreased LMR were significantly associated with poorer survival (p = 0.0001). Kaplan–Meier analysis confirmed reduced overall survival in patients with NLR ≥ 2.88 and improved survival in those with LMR ≥ 1.87. Cox regression analysis identified NLR as an independent predictor of mortality (HR = 2.05, p = 0.025), while LMR demonstrated a non-significant protective trend. Conclusions: These findings support the prognostic relevance of systemic inflammatory markers in OSCC. Unlike many previous studies evaluating inflammatory biomarkers alone, the present study additionally explored the relationship between NLR/LMR and histopathological invasion patterns, particularly WPOI, highlighting the potential interaction between systemic inflammation and tumor aggressiveness in OSCC. Further prospective, multicenter studies are required to validate these results and establish standardized clinical thresholds.