Significance of neutrophil to lymphocyte ratio as a predictor of outcome in head and neck cancer treated with definitive chemoradiation.

Background: The role of host immune system in carcinogenesis and response to treatment is increasingly studied, including predictive potential of circulating neutrophils and lymphocytes. The objective of the study was to evaluate the prognostic value of pre- and post-treatment neutrophil-to-lymphocyte (NLR) for treatment outcome in patients diagnosed with squamous cell carcinoma of head and neck (HNSCC) treated with definitive chemoradiation.

Materials and methods: Electronic medical records of patients were evaluated and NLR was calculated. Cox regression was used to assess the impact of selected variables on overall survival (OS), disease specific survival (DSS), progression free survival (PFS) and distant failure free survival (DFFS). Logistic regression was used to estimate odds ratios of complete response with NLR.

Results: 317 patients' records were included in the study. Increases in both pre-and post-NLR were associated with decreased OS in univariable analysis [hazard ratio (HR): 2.26 (1.25-4.07), p = 0.0068 and HR: 1.57 (1.03-2.37), p = 0.035 respectively). Post-NLR remained significant for OS in multivariable analysis [HR: 1.93 (1.22-3.1), p = 0.005] as well as for unfavorable DSS [HR: 2.31 (1.22-4.4), p = 0.01]. Pre-treatment NLR and nodal status correlated with shorter DFFS in multivariable analysis [HR 4.1 (1.14-14), p = 0.03 and HR 5.3: (1.62-18), p = 0.0062, respectively]. Strong correlation of increased both pre- and post-NLR with probability of clinical tumor response (CR) was found [odds ratio (OR): 0.23 (0.08-0.6), p = 0.003, and OR: 0.39 (0.2-0.8), p = 0.01 respectively].

Conclusion: NLR evaluated before and post treatment was a strong predictor of unfavorable treatment outcome and can be used for risk evaluation and clinical decision about treatment and post-treatment surveillance.