Prognostic role of pretreatment thrombocytosis on survival in patients with cervical cancer: a systematic review and meta-analysis

BACKGROUND: This meta-analysis summarized the prognostic role of an elevated platelet count before treatment on survival outcomes in patients with cervical cancer. METHODS: The PubMed, Embase, and Cochrane library electronic databases were systematically searched for studies reporting the effect estimates with 95% confidence intervals (CIs) of pretreatment thrombocytosis on survival from the database inceptions to December 2018. The pooled hazard ratios (HRs) with 95% CIs for overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were calculated using random-effects models. RESULTS: Nineteen retrospective studies that recruited 6521 patients with cervical cancer were eligible for this study. The summary results indicated that an elevated platelet count was significantly associated with a poor OS (HR 1.50; 95% CI 1.19–1.88; P = 0.001), PFS (HR 1.33; 95% CI 1.07–1.64; P = 0.010), and RFS (HR 1.66; 95% CI 1.20–2.28; P = 0.002). Sensitivity analysis indicated that the pooled PFS was variable after sequential exclusion of individual studies. The predictive value of pretreatment thrombocytosis on OS differed according to the publication year (P = 0.039), country (P = 0.013), and sample size (P = 0.029), and the role of pretreatment thrombocytosis on PFS could be affected by the study quality (P = 0.046). CONCLUSION: The findings of this study indicated that an elevated platelet count before treatment was associated with poor OS, PFS, and RFS. These results require further verification in large-scale prospective studies. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12957-019-1676-7) contains supplementary material, which is available to authorized users.