Validation of the pre-treatment neutrophil lymphocyte ratio as a prognostic factor in a large European cohort of renal cell carcinoma patients

Background: The neutrophil lymphocyte ratio (NLR) has been proposed as an indicator of systemic inflammatory response. Several studies suggest a negative impact of increased NLR for patient's survival in different types of cancer. However, previous findings from small-scale studies revealed conflicting results about its prognostic significance with regard to different clinical end points in non-metastatic renal cell carcinoma (RCC) patients. Therefore, the aim of our study was the validation of the prognostic significance of NLR in a large cohort of RCC patients. Methods: Data from 678 consecutive non-metastatic clear cell RCC patients, operated between 2000 and 2010 at a single centre, were evaluated retrospectively. Cancer-specific, metastasis-free, as well as overall survival (OS) were assessed using the Kaplan Meier method. To evaluate the independent prognostic significance of NLR, multivariate Cox regression models were applied for all three different end points. Influence of the NLR on the predictive accuracy of the Leibovich prognosis score was determined by Harrell's concordance index. Results: Multivariate analysis identified increased NLR as an independent prognostic factor for overall (hazard ratio (HR) = 1.59, 95% confidence interval (CI)= 1.10-2.31, P=0.014), but not for cancer-specific (HR= 1.59, 95% Cl =0.84-2.99, P=0.148), nor for metastasis-free survival (HR =1.39, 95% CI = 0.85-2.28, P=0.184). The estimated concordance index was 0.79 using the Leibovich risk score and 0.81 when NLR was added. Conclusion: Regarding patients' OS, an increased NLR represented an independent risk factor, which might reflect a higher risk for severe cardiovascular and other comorbidities. Adding the NLR to well-established prognostic models such as the Leibovich prognosis score might improve their predictive ability.