Platelet-lymphocyte ratio acts as an indicator of poor prognosis in patients with breast cancer

Platelet-lymphocyte ratio (PLR) is a hematological parameter which is investigated as a biomarker for prognosis in patients with breast cancer. Due to the controversial results from previous studies, we performed a meta-analysis. Databases of PubMed, Embase and Web of Science were searched to identify eligible studies. STATA version 12.0 was used for statistical analysis. Seven studies with 3,741 patients were ultimately included in this meta-analysis. High PLR was associated with poor overall survival (OS) (HR = 1.55, 95% CI = 1.07–2.25, p = 0.022) and disease-free survival (DFS) (HR = 1.73, 95% CI = 1.3-2.3, p < 0.001) in breast cancer patients. Subgroup analyses disclosed that elevated PLR could predict worse OS in Asian populations and poor DFS in both Asian and non-Asian patients. In addition, PLR remains a significant prognostic marker for OS in patients receiving systemic treatment (HR = 1.78, 95% CI = 1.06–2.99, p = 0.03) and patients receiving chemotherapy (HR = 2.82, 95% CI = 1.09–7.26, p = 0.032). High PLR also indicates poor DFS in patients who receive chemotherapy (HR = 2.6, 95% CI = 1.47–4.61, p = 0.001), surgery (HR = 1.8, 95% CI = 1.12–2.89, p = 0.016) and systemic treatment (HR = 2.03, 95% CI = 1.03–4.01, p = 0.042). Moreover, PLR was also in association with HER-2 positivity (OR = 1.48, 95% CI = 1.2–1.83, p < 0.001). In conclusion, this meta-analysis revealed that PLR could serve as an indicator of poor prognosis in patients with breast cancer.