Clinicopathological and prognostic significance of platelet count in patients with ovarian cancer

Aim: Increasing evidence indicates that platelet count is a useful biomarker of long-term outcomes in patients with ovarian cancer. However, the prognostic value of platelet count in patients with ovarian cancer remains controversial. We therefore conducted a meta-analysis aimed to investigate the prognostic role of the platelet count in patients with ovarian cancer. Method: A comprehensive search was performed from the databases of PubMed, Embase and the Cochrane Library until June 20, 2017. A total of 18 studies with 6754 patients were included. Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) and odds ratios and 95% CIs from each study were pooled. Results: The results demonstrated that elevated pretreatment platelet count was significantly related to poor survival from ovarian cancer; the pooled HRs for overall, progression-free and disease-free survival were 1.81 (95% CI 1.52-2.15), 1.48 (95% CI 1.24-1.75) and 1.39 (95% CI 1.19-1.61), respectively. Subgroup analyses were divided by ethnicity, sample size, FIGO stage, cut-off value of the platelet count, analysis method and Newcastle Ottawa Scale score, but the results did not show any significant change in the main results. Increased platelet count was also significantly associated with the FIGO stage, tumor differentiation, ascites, residual tumor mass, CA125 level, recurrence and metastasis. Conclusion: This meta-analysis revealed that an elevated platelet count pretreatment denotes a predictive factor of poor prognosis and unfavorable clinicopathological parameters for ovarian cancer patients.