Prognostic significance of platelet-to-lymphocyte ratio in non-small-cell lung cancer: a meta-analysis

BACKGROUND: The platelet-to-lymphocyte ratio (PLR) is a useful predictive factor in several cancers. However, the prognostic value of PLR in patients with non-small-cell lung cancer (NSCLC) is still indistinct. Therefore, it was necessary for us to perform a meta-analysis to assess the prognostic value of PLR in patients with NSCLC. METHODS: A systematic literature search was performed by using PubMed, EMBASE, and Web of Science databases for relevant studies until May 2015. Published studies investigating the association between PLR and overall survival (OS) and disease-free survival (DFS) were selected. Data from each eligible study were extracted. A meta-analysis was performed to analyze the prognostic value of PLR by using the hazard ratio (HR) and 95% confidence intervals (95% CI). RESULTS: A total of seven studies involving 1,554 patients were included in our meta-analysis. Our pooled results demonstrated that high PLR was associated with poor OS (HR: 1.60, 95% CI: 1.34–1.90, I(2)=22.3%, P(heterogeneity) = 0.259) and DFS (HR: 1.38, 95% CI: 1.11–1.73, I 2=0%, P(heterogeneity) = 0.482). Subgroup analysis between PLR and OS was performed in a further investigation. When the patients were segregated according to ethnicity, sample size, cutoff value, stage, and treatment modality, high PLR was also significantly correlated with OS. There was no significant heterogeneity among included studies. CONCLUSION: High PLR is associated with poor prognosis in patients with NSCLC. PLR may be a significant predictive biomarker in patients with NSCLC.