High Platelet-to-Lymphocyte Ratio Predicts Poor Prognosis and Clinicopathological Characteristics in Patients with Breast Cancer: A Meta-Analysis

Background. We aimed to evaluate the correlation of platelet-to-lymphocyte ratio (PLR) with prognosis and clinicopathological characteristics of breast cancer. Methods. The PubMed and Embase databases were searched. Hazard ratio (HR) with 95% confidence interval (CI) was used to summarize disease-free survival (DFS) and overall survival (OS). Odds ratio (OR) was used to summarize tumor clinicopathological characteristics. Results. High PLR was associated with poor DFS and OS (DFS: HR = 1.47, 95% CI = 1.16-1.85, and Tau(2) = 0.070; OS: HR = 1.88, 95% CI = 1.27-2.80, and Tau(2) = 0.192). A Galbraith plot indicated that the studies by Allan et al. and Cihan et al. contributed the heterogeneity of DFS and OS, respectively. There were significant differences in the incidence of high PLR between stage II-IV and stage I groups (OR = 1.86, 95% CI = 1.20-2.90, and Tau(2) < 0.001), between lymph node-positive and lymph node-negative groups (OR = 1.52, 95% CI = 1.22-1.91, and Tau(2) = 0.014), and between metastasis-positive and metastasis-negative groups (OR = 4.24, 95% CI = 2.73-6.59, and Tau(2) < 0.001). Conclusions. Our results indicated that PLR was associated with poor prognosis of breast cancer and adequately predicted clinicopathological characteristics.