Background : The prognostic value of pretreatment elevated platelet count remains controversial in lung cancer patients. We performed the present meta-analysis to determine the precise role of it in these patients.Methods: We performed a multiple search strategy in PubMed database, EMBASE and Cochrane Library to identify eligible studies. Disease-free survival (DFS) /Progress-free survival (PFS)/Time to progress(TTP) and Overall survival (OS) were used as outcomes with hazard ratio (HR) and its 95% confidence intervals (CIs). Heterogeneity among studies and publication bias were also evaluated.Results : A total of 39 studies including 16696 lung cancer patients were eligible in the analysis. Overall, the pooled analysis showed that pretreatment elevated platelet count was associated with poorer OS (HR= 1.47, 95%CI: 1.31-1.66, P
