Prognostic roles of neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in ovarian cancer: a meta-analysis of retrospective studies.

Purpose: The systemic inflammatory response markers have been reported to be associated with the prognosis of various cancers. We conducted this meta-analysis of retrospective studies to evaluate and identify the prognostic impact of neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) on ovarian cancer.
Methods: PubMed, EMBASE, and China National Knowledge Infrastructure databases were included to search for eligible studies. The following terms were used: "neutrophil to lymphocyte ratio", "NLR", "platelet to lymphocyte ratio", "PLR", "ovarian cancer", "ovary cancer", "ovarian carcinoma", "ovary carcinoma", "ovarian neoplasm", "ovary neoplasm", "ovarian tumor", and "ovary tumor". The random-effects model was chosen to estimate the pooled HR with 95% CI. Heterogeneity between studies was assessed by Higgins I ² value. The stability and heterogeneity of studies were analyzed by sensitivity analysis. Publication bias was examined by Egger's test and Begg's test with the funnel plots.
Results: 13 studies consisting of 3467 patients were considered for meta-analysis. We found that the high NLR had a poor prognostic impact on OS and PFS in ovarian cancer, with a pooled HR 1.70, 95% CI 1.35-2.15 and HR 1.77, 95% CI 1.48-2.12, respectively. Similarly, the results showed the high PLR adversely affected OS and PFS in ovarian cancer, with a pooled HR 2.05, 95% CI 1.70-2.48 and HR 1.85, 95% CI 1.53-2.25, respectively.
Conclusion: In conclusion, we found that both NLR and PLR had an unfavorable impact on PFS and OS of patients with ovarian cancer. Our meta-analysis supported that NLR/PLR could be effective prognostic predictors of ovarian cancer.