The Prognostic Value of Pretreatment Neutrophil-to-lymphocyte Ratio in Hypopharyngeal Cancer Receiving Definitive Radiation Therapy

Abstract

Neutrophil-to-lymphocyte ratio (NLR) had been reported as an important prognostic factor in a variety of cancers. We aimed to examine the association between pretreatment NLR and treatment response and to determine the prognostic significance of pretreatment NLR in hypopharyngeal cancer treated with definitive radiation therapy. We retrospectively reviewed the medical records of patients with hypopharyngeal cancer who had undergone definitive radiation therapy at the National Cheng Kung University Hospital, Taiwan, during the period from September 2009 to March 2014. We retrieved the following prognostic factors from patients’ medical records: age, sex, body mass index (BMI), comorbidity, performance status, pretreatment hemoglobin level, TNM stage based on AJCC 7th edition, tumor differentiation, and treatment duration. Pretreatment NLR was obtained from the results of blood tests within two weeks before starting curative treatment and calculated by dividing the number of the absolute neutrophil count by the number of lymphocyte count. Treatment response to radiation therapy was assessed with RECIST version 1.0. We used the chi-square test for the evaluation of the correlation between pretreatment NLR and treatment response. Next, we calculated overall survival (OS) and progression-free survival (PFS) by the Kaplan-Meier method and utilized the Cox proportional hazards model to compare survival curves between high pretreatment NLR (NLR ≥ 4) and low NLR (NLR < 4) patients. All statistical analysis was conducted using MedCalc software (version 15.2.2, Ostend, Belgium). We included 114 patients in this study. Median follow-up time was 27.8 months. Most patients were male (n = 111, 97.4%), and their median age at diagnosis was 55 (range, 32–83) years. They had a good performance status (Eastern Cooperative Oncology Group 0–1, n = 100, 87.7%); their median BMI was 21.9 (range, 13.0–31.5). Eighty (70.2%) patients had no comorbidity or mild comorbidity, and 34 (29.8%) patients had moderate to severe comorbidity. Eight (7.0%) cases had stage I or II disease; 15 (13.2%) cases had stage III disease; 73 (64.0%) cases had stage IVA disease, and 18 (15.8%) cases had stage IVB diseases. Chi-square test results revealed that high pretreatment NLR (NLR ≥ 4) was correlated with poor treatment response (p = 0.04*). Cox proportional analysis showed that pretreatment NLR was an independent prognostic factor for OS (HR = 1.7562; 95% CI, 1.0252-3.0084; p = 0.0413*). In hypopharyngeal cancer patients treated with definitive radiation therapy, we found that pretreatment NLR was correlated with treatment response. After controlling for known prognostic factors, pretreatment NLR was still an independent factor for overall survival. Incorporating pretreatment NLR may improve the performance of prognostic models.