Neutrophil-lymphocyte ratio as prognostic factor in metastatic breast cancer.

Objective: The aim of the study was to analyze the role of the neutrophil to lymphocyte ratio (NLR) as a prognostic factor in metastatic breast cancer (MBC). Methods: A retrospective cohort study including 359 recurrent MBC patients was performed. Clinical and pathological attributes were retrieved from patients' medical files and their importance in the overall survival were evaluated using the Cox univariate and multivariate proportional hazard models. A confidence interval of 95% was used to select significant variables and the Wald test was used to infer the best NLR cutoff value to discriminate into low and high categories. Results: In univariate analyses, the variables estrogen receptor (ER) and progesterone receptor (PR) expressions, previous treatment with adjuvant chemo, NLR, PLR (platelet-lymphocyte ratio), age at diagnosis and the main metastatic site (bone/lymph node, visceral or central nervous system) variables were significant to determine the hazards. After filtering the collinear variables, the final model was tested with 6 variables based on 339 patients and the NLR at the time of the recurrence diagnosis (NLR_rec), the hormone receptor (ER or PR) status and the age at diagnosis were considered significant. The best NLR_rec value to discriminate against patients was 4.43 (Wald test= 51.7) and there were 239 patients categorized as low and 111 as high NLR category. The median overall survival time was 18 and 4 months in NLR-low and NLR-high groups, respectively (p< 0.001). Conclusion: NLR is an independent prognostic factor in recurrent MBC patients.