Evaluating the Neutrophil-Lymphocyte Ratio as a Predictor of Long-Term Oncological and Survival Outcomes in Patients Treated Surgically for Breast Cancer

Background: Neutrophil-lymphocyte ratio (NLR) is an emerging prognostic biomarker with potential utility in solid malignancies. Routine draw of full blood count in preoperative workup positions NLR as a cost-effective adjunct in risk stratification. This project explores associations between preoperative NLR and breast cancer outcomes. Methods: This retrospective cohort study reviewed an institutional database of breast cancer patients undergoing primary curative surgery at University Hospital Limerick from January 1, 2010 to June 1, 2017. Primary endpoints included recurrence at 5 years, disease free survival (DFS) and OS (OS). Regression modelling examined associations between preoperative NLR ≥2.5 and endpoints, controlling for confounders. Results: Median preoperative NLR was 2.63 (SD 1.42). The cohort comprised 579 patients, with a recurrence rate of 15.7% (6% local recurrence and 9.7% distant metastasis). 106 (18.3%) patients were deceased at the administrative censoring time. Patients with NLR ≥ 2.5 had a 2-fold increase in rate of distant metastasis at 5 years (OR 2.00, 95% CI, 1.05-3.81, P = .036) and experienced worse OS (HR 1.84, 95% CI, 1.20-2.84, P = .006). Outcomes between NLR ≥2.5 and local recurrence at 5 years, as well as NLR ≥2.5 and DFS were equivocal. Conclusions: Preoperative NLR ≥2.5 was found to be an independent predictor of distant metastasis at 5 years and an independent predictor of OS, following adjustment of confounders. This finding is consistent with published literature and may help risk stratify patients at higher risk of breast cancer recurrence.