Establishing the prognostic value of platelet-to-lymphocyte ratio in cervical cancer: a systematic review and meta-analysis.

OBJECTIVE

The aim of this study was to conduct a meta-analysis to establish the prognostic value of platelet-to-lymphocyte ratio in cervical cancer.

METHODS

We conducted a search in Medline and Embase datasets for articles published until May 1, 2018 to perform a meta-analysis to establish the prognostic value of platelet-to-lymphocyte ratio in cervical cancer. The primary survival outcomes were overall survival and progression-free survival. The pooled hazard ratios (HRs) and 95% confidence intervals (95% CIs) were combined to calculate overall effects. Cochran's Q test and Higgins' I statistics were employed to estimate the heterogeneity. In addition, the subgroup analysis, sensitivity analysis, and meta-regression were performed to identify the source of heterogeneity. Egger's linear regression test and Begg's funnel plot and the trim and fill methods were employed to evaluate the publication bias.

RESULTS

A total of 2616 patients from eight studies were enrolled in the meta-analysis. Significant association was observed between elevated platelet-to-lymphocyte ratio and a worse overall survival, with a combined HR of 1.49 (95% CI 1.24 to 1.79, I=32.8%). Elevated platelet-to-lymphocyte ratio was significantly associated with a worse progression-free survival, with a combined HR of 1.65 (95% CI 1.17 to 2.33, I = 49.4%). Subsequently, sensitivity analysis, subgroup analysis, and meta-regression model containing six predominant factors were applied to trace the origin of heterogeneity. However, no significant factors or studies were explored as the potential source of heterogeneity.

CONCLUSION

Elevated pre-treatment platelet-to-lymphocyte ratio may be an adverse prognostic factor for overall survival and progression-free survival in patients with cervical cancer. Further investigations are warranted to determine the exact mechanism by which platelet-to-lymphocyte ratio impacts survival outcomes in cervical cancer.