Exploratory Analysis of Neutrophil-to-Lymphocyte Ratio Dynamics and Pathologic Response to Neoadjuvant Nivolumab in Head and Neck Squamous Cell Carcinoma

Neutrophil to lymphocyte ratio (NLR) is an inflammatory index with prognostic value in a variety of solid tumors. It is easily derived from routine blood tests, and elevated ratios have shown association with poor outcomes in several settings. However, the association of NLR with response to neoadjuvant PD-1 inhibitors in head and neck squamous cell carcinoma remains unclear. We performed a hypothesis-generating receiver operating characteristic (ROC) analysis of 42 patients to explore associations between pathologic response to neoadjuvant nivolumab and: (1) baseline pre-treatment NLR, (2) on-treatment NLR, and (3) percent change in NLR between these two time points. Percent change in NLR demonstrated the highest area under the curve (AUC) for major pathologic response (0.67, 95% CI: 0.47–0.87) and partial response (0.65, 95% CI: 0.48–0.82), though these findings were not statistically significant. A >22.1% increase in NLR from baseline was associated with failure to achieve major or partial pathologic response, with specificity of 0.82 (95% CI: 0.67–0.92) and sensitivity of 0.58 (95% CI: 0.25–0.84), though again findings were not statistically significant. These exploratory results warrant validation in larger cohorts.