The Pre-Treatment Neutrophil-Lymphocyte Ratio: a Useful Tool in Predicting Non-Sentinel Lymph Node Metastasis in Breast Cancer Cases.

Background: The sentinel lymph node (SLN) biopsy is a highly accurate predictor of overall axillary nodal status in early breast cancer patients. There is however, still a debate on which patients with a positive SLN can benefit from axillary lymph node dissection (ALND). Numerous studies have been designed to identify variables that are predictive of non-SLN metastasis to avoid a complete ALND. The aim of this study was to determine whether the pre-treatment neutrophil-lymphocyte ratio (NLR) can be a predictive factor of non-SLN metastasis in early breast cancer patients. Materials and Methods: The records of 214 consecutive patients with cT1-3N0 invasive breast cancer who had undergone intraoperative SLN evaluation at Songklanagarind Hospital between the 1stof March 2011 and the 30thof May 2016 were examined. Data on patient demographics, tumor variables and NLR were collected and factors for non-SLN metastasis were analyzed using multivariate logistic regression. The power of the NLR was quantified with receiver operating characteristics (ROC) curves as measured by the areas under curves (AUC). Results: Multivariate analysis established presence of lymphovascular invasion (OR 8.4, 95%CI 2.3-31.3, p=0.002), macrometastasis (OR 6.6, 95%CI 1.8-24.7, p=0.005), and NLR (OR 2.3, 95%CI 1.1-4.8, p=0.033) as predictive factors of non-SLN metastasis with statistical significance. The AUC for NLR was 0.7 (95%CI 0.6-0.8) with an optimal cut-off of 2.6 giving a sensitivity of 62%, a specificity of 83.8%, a positive predictive value of 77.3% and a negative predictive value of 70.5%. Conclusion: Pre-treatment NLR is a useful diagnostic aid for predicting additional non-SLN metastasis.