Prognostic value of neutrophil-to-lymphocyte ratio in castration resistant prostate cancer: Single-centre study of Nigerian men.

BACKGROUND: Elevated neutrophil-to-lymphocyte ratio (NLR) has been suggested to be a useful prognosticator of overall survival (OS) in several cancers including castration resistant prostate cancer. However, its utility in black populations known to have benign ethnic neutropenia is unknown. We evaluated the prognostic value of NLR in Nigerian men with CRPC in terms of OS. MATERIALS AND METHODS: We retrospectively analysed 58 patients with castration resistant prostate cancer who received androgen deprivation therapy (ADT) and docetaxel chemotherapy at our institution. Baseline NLR was calculated from available complete blood counts. NLR cut-off point value was determined based on receiver operator characteristic (ROC) curves for mortality. A multivariate analysis was performed to investigate the association between NLR and OS. RESULTS: Based on the ROC curves, the NLR (AUC 0.85, 95% CI 0.74-0.97, P = 0.0001) cut-off point was determined to be 1.8. This cut-off point has a sensitivity of 92% and specificity of 70%. Median OS was 20 months (95% CI 14-27 months); the median OS in patients with NLR <1.8 and those with NLR of ≥1.8 was 40 months and 12 months respectively. Kaplan-Meier plots showed that a higher NLR of ≥1.8 correlated significantly with an increased risk of mortality, Log rank P = 0.001. Multivariate Cox regression analyses confirmed NLR as an independent prognostic biomarker for OS (HR = 1.49, 95% CI: 1.18-1.87). CONCLUSIONS: This study demonstrated that NLR is a useful prognostic biomarker in Nigerian men with CRPC and that elevated baseline NLR ≥1.8 is associated with poorer OS.