Prognostic Role of Neutrophil to Lymphocyte Ratio in Ovarian Cancer: A Meta-Analysis

OBJECTIVE: The aim of the study was to investigate the prognostic role of neutrophil to lymphocyte ratio in ovarian cancer. Growing number of articles reported the relationship between neutrophil to lymphocyte ratio and prognosis in ovarian cancer, but the results remains inconclusive. The meta-analysis was conducted to analyze the association of pretreatment neutrophil to lymphocyte ratio with overall survival and progression-free survival. METHODS: We performed a systematic literature research of PubMed, EMBASE, Medline, and Cochrane library for relevant studies up to October 8, 2017. The quality of included studies was assessed by the Newcastle-Ottawa Quality Assessment Scale. The hazard ratio and corresponding 95% confidence intervals were calculated. We checked the heterogeneity by the Q test and Higgins I-squared statistic. Begg funnel plot and Egger linear regression test were also applied for ascertain publication bias. All of the statistical analyses were performed using STATA version 12.0. RESULTS: A total of 12 studies with 4046 patients were included in our study. The results indicated that depressed neutrophil to lymphocyte ratio was significantly correlated with higher overall survival (hazard ratio = 1.409, 95% confidence intervals = 1.112-1.786, P = .005) and progression-free survival (hazard ratio = 1.523, 95% confidence intervals = 1.187-1.955, P = .001) in ovarian cancer. Subgroup analysis by ethnicity of overall survival and progression-free survival showed that the prognostic effect of neutrophil to lymphocyte ratio was found both in Asians and Caucasians. CONCLUSION: Patients with depressed neutrophil to lymphocyte ratio had a higher overall survival and progression-free survival in ovarian cancer. This meta-analysis provided neutrophil to lymphocyte ratio as an available predictor of overall survival and progression-free survival for patients with ovarian cancer.