AB071. SOH24AB₁84. Evaluating preoperative neutrophil-lymphocyte ratio as a predictive biomarker in primary breast cancer

Background: Neutrophil-lymphocyte ratio (NLR) is an established strong predictor of mortality in a variety of solid organ malignancies. Nevertheless, there is limited evidence supporting such in breast cancer. The aim of this work is to evaluate the association between preoperative NLR and breast cancer oncological and survival outcomes. Methods: A retrospective cohort study was performed. Patients were identified from a prospectively maintained institutional database of breast cancer patients undergoing primary curative surgery at University Hospital Limerick from January 1, 2010 to June 1, 2017. Primary endpoints studied were disease-free survival (DFS) and overall survival (OS). Univariable and multivariable Cox regression examined survival outcomes between groups of patients with NLR <2.5 and NLR ≥2.5. Results: After applying exclusion criteria, 579 patients were included. Median preoperative NLR was 2.63 (standard deviation: 1.42), with NLR ≥2.5 in 59.7% of patients (n=346). The mortality rate was 18.1% (n=105). The recurrence rate was 15.7% (n=91), with 6% local recurrence and 9.7% distant metastasis rates respectively at five years. Patients with NLR ≥2.5 were significantly associated with poorer OS hazard ratio (HR): 1.71, 95% confidence interval (CI): 1.12–2.60, P=0.011, with equivocal outcomes observed for DFS (HR: 1.10, 95% CI: 0.91–1.34, P=0.300). Conclusions: Preoperative NLR ≥2.5 was found to be an independent predictor of breast cancer OS. Prospective validation of these provisional results is required before incorporation into clinical practice to aid patient prognostication.