Prognostic value of neutrophil-to-lymphocyte ratio in breast cancer

Inflammation is an essential component of pathogenesis and progression of cancer. A high neutrophil-to-lymphocyte ratio (NLR) is considered as a prognostic indicator for breast cancer. This meta-analysis was conducted to establish the overall accuracy of the NLR test in the diagnosis of breast cancer. A comprehensive search of the literature was conducted by using PubMed, Web of Science and China National Knowledge Infrastructure (CNKI). Published studies dating up to July 2014 and 4,293 patients were enrolled in the present study. In order to evaluate the association between NLR and overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS) or cancer specific survival (CSS), the hazard ratios (HRs) and their 95% confidence intervals (CIs) were extracted. OS was the primary outcome. The results suggested that increased NLR was a strong predictor for OS with HR of 2.28 (95% CI = 1.08-4.80, Pheterogeneity < 0.001). Stratified analyses indicated that a high NLR appeared to be a negative prognostic marker in Caucasian populations (HR = 4.53, 95% CI = 3.11-6.60, Pheterogeneity  = 0.096), multivariate analysis method (HR = 2.10, 95% CI = 1.52-2.89, Pheterogeneity = 0.591), and mixed metastasis (HR = 4.53, 95% CI = 3.11-6.60, Pheterogeneity = 0.096). Elevated NLR was associated with a high risk for DFS (HR = 1.38, 95% CI = 1.09-1.74, Pheterogeneity = 0.050) and in subgroups of multivariate analysis (HR = 1.64, 95% CI = 1.25-2.14, Pheterogeneity = 0.545) and mixed metastasis (HR = 1.99, 95% CI = 1.28-3.09, Pheterogeneity = 0.992). In summary, NLR could be considered as a predictive factor for patients with breast cancer.