The systemic immune-inflammation index (SII) correlates with patient survival in various types of solid malignancies, including gastro-intestinal malignancies and non-small cell lung cancer (NSCLC). However, limited information is available on the prognostic implication of SII in head and neck malignancies, specifically oral cavity squamous cell carcinoma (OCSCC).
We retrospectively reviewed 222 patients with available laboratory data who underwent a resection of curative intent for patients with OCSCC. SII was calculated within 45 days prior to surgical resection as platelet count × neutrophil count/lymphocyte count. Chi-squared analysis was used to evaluate the association between an initial positive margin and clinicopathologic parameters. A Kaplan-Meier analysis was performed to estimate freedom from locoregional recurrence (FFLR), disease-free survival (DFS), overall survival (OS), and disease-specific survival (DSS) rates, with Cox regression analysis used to determine absolute hazards.
At a median follow-up of 30.6 months, 2-year FFLRR, DFS, OS, and DSS rates were 80.1%, 63.9%, 76.4%, and 81.6%, respectively. A high SII (>1047) was associated with ECOG performance status ≥2 (28.6% vs 8.7%, p<0.001), size of primary disease >20 mm (69.4% vs 45.7%, p=0.003), DOI >10 mm (59.2% vs 28.9%, p<0.001), presence of perineural invasion (PNI) (53.1% vs 27.2%, p<0.001), and presence of extracapsular extension (ECE) (32.7% vs 15.6%, p=0.008). On multivariate analysis, a low SII (<1047) at diagnosis was independently associated with an improved FFLRR (HR: 0.382, 95% CI: 0.21-0.694, p=0.002), DFS (HR: 0.440, 95% CI: 0.286-0.679, p<0.001), OS (HR: 0.516, 95% CI: 0.319-0.836, p=0.007) and DSS (HR: 0.416, 95% CI: 0.222-0.781, p=0.006) rates.
SII values at diagnosis were associated with patient performance status and disease extent at the time of diagnosis. A low SII was independently associated with improved disease control rates and patient survival. Further evaluation of SII is warranted in this population to validate these prognostic findings in large patient cohorts and to determine the ability of SII to predict for treatment outcomes.