Neutrophil to Leukocyte Ratio Correlates to Patient Survival Outcomes in Colorectal Cancer

Abstract

Introduction: High neutrophil to lymphocyte ratios (NLR) are indicative of inflammation and may be associated with cancer progression. NLR greater than 4 has been shown to be inversely associated with overall survival (OS) and disease free survival (DFS) in patients with solid tumors. In our study, we tested for such an association between NLR and survival in patients with colorectal cancer (CRC). Methods: Neutrophil and lymphocyte data was obtained from the medical records of 4,080 consented CRC patients. Review of the white blood cell count and differential collected as the part of the preoperative evaluation was utilized to calculate NLR for patients with CRC. Patients were segregated into quartiles by NLR values. NLR was considered in the context of disease stage, DFS, median OS, and death. Results: Higher NLR was associated with increased risk of death among CRC patients both in univariate (p=3 x10-16) and in multivariate models adjusted for age, sex, BMI, grade, stage and smoking (p=1.58 x10-7 ). The risk of death for patients in the top three NLR quartiles was greater than the risk of death for patients with first quartile NLR values, which ranged between 0 to 2.2 and served as the reference base. The hazard ratio (HR) was 1.42 (p=0.00114) for CRC patients with NLR in the second quartile (NLR :2.2-3.1); 1.34 (p=0.00598) for those patients in the third quartile, NLR (3.1-4.61); and 1.92 (p=8.8 x10-10) for those patients in the fourth quartile (NLR > 4.61). Within disease stages I, II and III, NLR for those who died exceeded the NLR for survivors (p < 0.05). No difference in NLR was observed for stage IV CRC survivors or deceased. Time-dependent receiver operating characteristic (ROC) analysis suggests that NLR = 3.64 has positive predictive value for five year OS. Conclusion: Our observation of increased NLR corresponding to declines in DFS and OS in this cohort is consistent with reports in the literature. NLR has not been widely incorporated into prognostication models for CRC, but has the potential to enhance current prognostication.