Background: The neutrophil-to-lymphocyte ratio (NLR) is a strong predictor of mortality in patients with colorectal, gastric, hepatocellular, pancreatic, and lung cancer. To date, the utility of NLR to predict mortality in breast cancer patients has not been studied. Therefore, the aim of our study was to determine whether the NLR is predictive of short- and long-term mortality in breast cancer patients.
Methods: Our observational study used an unselected cohort of breast cancer patients treated at the Staten Island University Hospital between January 2004 and December 2006. A total of 316 patients had a differential leukocyte count recorded prior to chemotherapy. Survival status was retrieved from our cancer registry and Social Security death index. Survival analysis, stratified by NLR quartiles, was used to evaluate the predictive value of NLR.
Results: Patients in the highest NLR quartile (NLR > 3.3) had higher 1-year (16% vs 0%) and 5-year (44% vs 13%) mortality rates compared with those in the lowest quartile (NLR < 1.8) (P < .0001). Those in the highest NLR quartile were statistically significantly older and had more advanced stages of cancer. After adjusting for the factors affecting the mortality and/or NLR (using two multivariate models), NLR level > 3.3 remained an independent significant predictor of mortality in both models (hazard ratio 3.13, P = .01) (hazard ratio 4.09, P = .002).
Conclusion: NLR is an independent predictor of short- and long-term mortality in breast cancer patients with NLR > 3.3. We suggest prospective studies to evaluate the NLR as a simple prognostic test for breast cancer.