Our goal was to assess the correlation of immune parameters with the response to induction chemotherapy (ICT) in head and neck squamous cell carcinoma (HNSCC) patients. Pretreatment biopsies from 64 patients with HNSCC that received ICT were assessed for PD-L1 protein expression and density of CD8+ and FOXP3+ tumor infiltrating lymphocytes (TIL). In addition, the neutrophil-to-lymphocyte ratio (NLR) was calculated from pretreatment whole blood counts. In total, 55% of cases exhibited PD-L1 combined proportion score (CPS) positivity (≥1% stained cells). PD-L1 CPS positivity correlated with a high density of both CD8+ (p = 0.01) and FOXP3+ (p < 0.001) TILs. There was no correlation between PD-L1 expression or TIL density and NLR values. In univariate analyses, the absence of PD-L1 CPS expression (p = 0.042) and a high NLR (p = 0.034) were significantly correlated with response to ICT. Neither CD8+ TIL (p = 0.99) nor FOXP3+ TIL densities (p = 0.71) were associated with response to ICT. In multivariate analysis, only a high NLR was associated with response to ICT (HR = 4.06, 95% CI = 1.06-15.5, p = 0.04). In addition, a high NLR was also independently associated with lower disease-specific (p = 0.03) and overall survival rates (p = 0.04), particularly in the subset of patients who received definitive surgical treatment. These results suggest that NLR could emerge as a predictive biomarker of response to ICT.
Keywords: PD-L1; chemotherapy; hypopharynx; larynx; neutrophil-to-lymphocyte ratio; squamous cell carcinoma; tumor infiltrating lymphocytes.