Association of Absolute Neutrophil Count With Outcomes in Patients With Head and Neck Cancer Receiving Definitive Chemoradiation

PURPOSE: Systematic inflammation plays an integral role in tumor development and metastasis. High neutrophil counts, among various peripheral blood biomarkers, have been shown to be associated with worse outcomes in multiple cancer types. To evaluate the absolute neutrophil count (ANC) as a prognostic biomarker in head and neck cancer, we performed an observational cohort study of patients undergoing definitive chemoradiation. METHODS: Our institutional database was queried for patients with non-metastatic head and neck cancer who underwent definitive chemoradiation between June 2007 and April 2023. ANC was analyzed as a continuous variable. Cox multivariable analysis (MVA), Fine-Gray MVA, and propensity score matching with its median value as a cutoff were performed. Subgroup analyses were performed among p16-positive cohorts. RESULTS: A total of 668 patients who met our criteria. Median follow up was 30.3 months (interquartile range 9.9-60.7). Elevated ANC as a continuous variable was associated with worse overall survival (OS; adjusted hazards ratio [aHR] 1.02, 95% confidence interval [CI] 1.01-1.04, p = 0.003), progression free survival (PFS; aHR 1.03, 95% CI 1.01-1.04, p < 0.001), and distant failure (DF; aHR 1.03, 95% CI 1.01-1.05, p = 0.007), but not locoregional failure (LRF; aHR 1.02, 95% CI 1.00-1.05, p = 0.10). Similar findings were noted among 278 matched pairs. Among 344 patients with p16-positive tumors, high ANC was associated with worse OS (aHR 1.03, 95% CI 1.00-1.06, p = 0.046), PFS (aHR 1.05, 95% CI 1.02-1.07, p < 0.001), LRF (aHR 1.08, 95% CI 1.05-1.12, p < 0.001), and DF (aHR 1.04, 95% CI 1.01-1.08, p = 0.02). CONCLUSIONS: Our study suggested that elevated ANC was an independent, adverse prognostic factor for worse survival and distant metastasis outcomes. It was also associated with worse locoregional failure among patients with p16-positive tumors.