The prognostic and predictive role of the neutrophil-to-lymphocyte ratio and the monocyte-to-lymphocyte ratio in early breast cancer, especially in the HER2+ subtype

PURPOSE: The aim of this study was to investigate the prognostic impact of two systemic inflammatory markers, the neutrophil-to-lymphocyte ratio (NLR) and the monocyte-to-lymphocyte ratio (MLR), and their possible predictive role regarding the efficacy of adjuvant trastuzumab, in 209 early breast cancer cases, 107 of which were HER2-positive. METHODS: Baseline NLR and MLR values were divided into two groups, high and low, according to cut-off-points determined from the ROC curve (2.2 for NLR and 0.22 for MLR). Cox’s model was utilized for survival analyses. RESULTS: High NLR and MLR correlated with poor overall survival (OS) and breast cancer specific survival (BCSS) among all the patients (p ≤ 0.030). Among the HER2+ patients whose adjuvant treatment did not include trastuzumab (n = 64), the survival rates were remarkably lower in patients with a high NLR as compared to those with low; 31% vs. 71% for OS and 42% vs. 74% for BCSS (p ≤ 0.014). Similarly, high MLR correlated with poor survival among these patients (p ≤ 0.020). On the contrary, among the patients who had received adjuvant trastuzumab (n = 43), NLR or MLR did not correlate with survival. Furthermore, trastuzumab was beneficial for the HER2+ patients with high NLR/MLR, while the survival of the HER2+ patients with low NLR/MLR was good irrespective if they received adjuvant trastuzumab. CONCLUSIONS: Our results suggest that trastuzumab modulates the systemic inflammatory conditions and overcomes the poor prognostic impact of high NLR/MLR. This finding may also provide a rationale for combining trastuzumab with immuno-oncological treatments in HER2+ breast cancer. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10549-020-05925-7) contains supplementary material, which is available to authorized users.