Exploratory Analysis of the Neutrophil-to-Lymphocyte Ratio (NLR) and Mucositis Severity in Head and Neck Cancer Patients Undergoing Radiotherapy-Based Treatment: A Retrospective Study

Background/Objectives: The neutrophil-to-lymphocyte ratio (NLR) is a simple biomarker reflecting systemic inflammatory status and has been investigated in head and neck cancer (HNC) as a potential prognostic indicator. Its role in relation to radiotherapy-related toxicity remains uncertain. The aim of this study was to provide a descriptive evaluation of NLR values in relation to oral mucositis severity and swallowing-related quality of life in patients undergoing radiotherapy-based treatment. Methods: We retrospectively evaluated 32 patients with locally advanced HNC treated with radiotherapy, with or without concomitant chemotherapy, in the definitive or adjuvant setting (March 2025–January 2026). NLR was calculated at baseline (T0), at a predefined mid-treatment timepoint (T3), and during week 6 of treatment (T6). Mucositis severity was assessed using CTCAE and the Oral Mucositis Assessment Scale (OMAS), while swallowing-related quality of life was measured using the MD Anderson Dysphagia Inventory (MDADI). Relationships between NLR values and toxicity endpoints were descriptively assessed using Spearman correlation analysis. Results: No statistically significant correlations were observed between NLR values and OM severity or swallowing-related outcomes at any evaluated timepoint. At T3, non-significant correlations were observed between NLR and CTCAE mucositis grade and between NLR and MDADI global score. No statistically significant correlations were observed between NLR values and OMAS at any evaluated timepoint. Conclusions: In this retrospective cohort, no association between NLR and radiotherapy-related mucositis severity or swallowing-related quality of life was demonstrated. These findings are descriptive and limited by the small sample size, the retrospective design, and the absence of control for potential confounding factors. No inferential or causal conclusions can be drawn. Further prospective studies with larger and more homogeneous cohorts are required to better characterize NLR behavior in this clinical setting.