Association of neutrophil-to-lymphocyte ratio with severe radiation-induced mucositis in pharyngeal or laryngeal cancer patients: a retrospective study

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation that informs clinical decisions regarding recurrence and overall survival in most epithelial cancers. Radiotherapy for head and neck cancer leads to mucositis in almost all patients and severe radiation-mucositis affects their quality of life (QOL). However, little is known about the NLR for severe mucositis. Therefore, this study aimed to show the association between the NLR and severe radiation-induced mucositis in hypopharyngeal or laryngeal cancer patients. METHODS: In this retrospective study, we determined the incidence of grade 3 mucositis in 99 patients who were receiving definitive radiotherapy or chemoradiotherapy (CRT) for hypopharyngeal or laryngeal cancer. We performed univariate and multivariate logistic regression analyses to investigate the characteristics of grade 3 mucositis. Kaplan–Meier curves and log-rank tests were used to evaluate the occurrence of grade 3 mucositis between two groups with high (NLR > 5) or low (NLR < 5) systemic inflammation. RESULTS: The incidence of grade 3 mucositis was 39%. Univariate logistic regression analysis showed that the NLR (Odd ratio [OR] = 1.09; 95% confidence interval [CI] = 1.02–1.16; p = 0.016) and smoking (OR = 1.02; 95% CI = 1.00–1.03; p = 0.048) were significantly associated with grade 3 mucositis. Multivariate logistic regression analysis showed that the NLR was independently associated with grade 3 mucositis (OR = 1.09; 95% CI = 1.01–1.17; p = 0.021). Kaplan–Meier curves also showed that patients with higher NLR (NLR > 5) prior to radiotherapy developed grade 3 mucositis more frequently than those with lower NLR during radiotherapy (p = 0.045). CONCLUSION: This study suggests that a higher NLR is a risk factor and predictor of severe radiation-induced mucositis in hypopharyngeal or laryngeal cancer patients.