Exploring neutrophil-lymphocyte ratio as a predictor of postoperative breast cancer overall survival

Abstract Introduction Neutrophil-lymphocyte ratio (NLR) is an established strong predictor of mortality in colorectal, hepatocellular, gastric, pancreatic and lung cancers, however there is limited evidence regarding breast cancer. The relationship of the host immune system and tumour biology plays a known integral role in oncological outcomes. The NLR provides an approximate quantification of host inflammatory response in advancing or more aggressive tumours. Routine inclusion of the full blood count in preoperative workup thereby offers a possible cost-effective prognostic biomarker. This project explores the association between preoperative NLR and breast cancer overall survival. 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. The primary endpoint studied was overall survival. Log-rank testing examined overall survival between groups of patients with NLR <2.5 and NLR ≥2.5. Results In the included cohort of 579 cases, the mortality rate was 18% (n=105). The cohort had a median preoperative NLR of 2.63 (SD 1.42). Patients with NLR ≥ 2.5 were significantly associated with poorer overall survival (HR 1.71, 95% CI 1.12 to 2.60, p=0.011). Median survival time is not available for this dataset at this time and will be reported upon longer follow up. Conclusion Preoperative NLR ≥2.5 was found to be an independent predictor of breast cancer overall survival. Analysis of this data is ongoing to adjust for confounders, as well as evaluate recurrence free survival.