Histopathological Evaluation of Systemic Immune-Inflammation Index (SII) in Oral Squamous Cell Carcinoma

Abstract

Introduction: Oral squamous cell carcinoma (OSCC) shows considerable biological heterogeneity in clinical behaviour and prognosis. Conventional histopathological grading remains important but may not fully reflect tumour aggressiveness or the systemic immune-inflammatory status of the host. The systemic immune-inflammation index (SII), derived from peripheral blood neutrophil, lymphocyte and platelet counts, may provide an adjunctive indicator of host inflammatory and immune response in OSCC. Aim: This study evaluated SII in patients with OSCC and correlated SII values with histopathological grades. Materials and Method: A total of 60 subjects were included, comprising 20 healthy controls and 40 histopathologically confirmed OSCC cases. Before treatment, 2 mL of venous blood was collected under aseptic conditions, and complete blood count analysis was performed using an automated haematology analyser. SII was calculated using the formula: platelet count × neutrophil count / lymphocyte count. Descriptive statistics were expressed as mean ± standard deviation. The independent Student’s t-test was used to compare SII values between healthy controls and OSCC patients, and one-way ANOVA with post hoc analysis was used to assess differences across histopathological grades. A p-value < 0.05 was considered statistically significant. Results: The mean SII was significantly higher in OSCC patients (2195.98 ± 1165.98) than in healthy controls (429.87 ± 50.20) (p < 0.001). SII values increased progressively from well-differentiated to poorly differentiated OSCC, and this association was statistically significant (p < 0.05). Conclusion: The findings suggest that SII is elevated in OSCC and shows a positive association with poorer histopathological differentiation. SII may serve as a simple, cost-effective adjunctive inflammatory biomarker for supporting histopathological assessment in OSCC.