Prognostic Significance of Neutrophil-to-Lymphocyte Ratio in Ovarian Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Abstract

Background and Aims: Published data on the prognostic role of neutrophil-to-lymphocyte ratio (NLR) in ovarian cancer are controversial. We conducted this meta-analysis to obtain a more accurate assessment of prognostic significance of NLR in ovarian cancer. Materials and Methods: We conducted a systematic literature search using the electronic databases PubMed, Web of Science, and Embase up to May 2016. Hazard ratio (HR) and odd ratio (OR) with 95% confidence interval (95% CI) were calculated. Subgroup analyses were carried out to explore the source of heterogeneity. Statistical analysis was performed using Stata 10.0. Results: A total of 12 studies, consisting of 3,854 patients, which met our criterion were selected in this meta-analysis. Our pooled results showed that high pre-treatment NLR level was significantly associated with poorer overall survival (OS) (HR: 1.69, 95% CI 1.29-2.22) and shorter progression free survival (PFS) (HR 1.63, 95% CI 1.27–2.09). Additionally, increased NLR was also significantly correlated with advanced FIGO stage (OR 2.32, 95% CI1.79-3.00), higher serum level of CA-125 (OR 3.33, 95% CI 2.43-4.58), more extensive ascites (OR 3.54, 95% CI 2.31-5.42) as well as less chemotheraputic response (OR 0.53, 95% CI 0.40-0.70). The findings from most of subgroup meta-analyses were consistent with those from the overall meta-analyses. Conclusions: Elevated pre-treatment NLR could served as a predicative factor of poor prognosis for ovarian cancer patients.