Neutrophil to Lymphocyte Ratio in Castration-Resistant Prostate Cancer Patients Treated With Daily Oral Corticosteroids.

Abstract

The neutrophil to lymphocyte ratio (NLR) has been shown to be highly prognostic across many tumor types, and predictive of treatment outcome in advanced prostate cancer, and has been postulated to be an indirect measure of tumor inflammation. We evaluated the effect of low-dose steroids on NLR in men suffering from castration-resistant prostate cancer (CRPC). The NLR was evaluated in a prospective randomized phase II trial that compared prednisolone 5 mg twice daily and dexamethasone 0.5 mg daily administered to 75 chemotherapy and abiraterone/enzalutamide-naive CRPC patients. NLR was examined at baseline (BL), after 6 and 12 weeks of corticosteroid treatment; associations with >50% prostate-specific antigen (PSA) response, duration of response (PSA progression-free interval), and overall survival (OS) were tested using logistic regression and Cox regression analysis. The median NLR for all evaluable patients was 2.6 at BL; 2.9 at 6 weeks; and 4.0 at 12 weeks. After low-dose corticosteroid initiation, 46 patients had a decline in PSA with 24 confirmed responders. BL NLR (log10) associated with a PSA response (odds ratio, .029, 95% confidence interval [CI], .002-.493; P= .014), and with the extent of the PSA decline (P= .009). A favorable BL NLR (less than median) associated with a 5.5-fold higher odds of a PSA >50% response (95% CI, 1.3-23.9; P= .02). Higher BL NLR (log10) associated with a shorter time to PSA progression (hazard ratio [HR], 9.5; 95% CI, 2.3-39.9; P= .002). In multivariate analysis BL NLR as a discrete variable was independently associated with PSA progression (HR, 3.5; 95% CI, 1.5-8.1; P= .003). NLR at 6 weeks was also associated with duration of benefit; in the favorable NLR category time to PSA progression was 10.8 months, for those who converted to an unfavorable (greater than median) category 4.5 months, and for those remaining in a unfavorable category only 1.5 months (95% CI, 0.5-2.5; P= .003). OS was 33.1 months (95% CI, 24.2-42.0) and 21.9 months (95% CI, 19.3-24.4) for those with an favorable and unfavorable BL NLR, respectively. Treatment-naive CRPC patients with a high BL or during-treatment NLR appear not to benefit from low-dose corticosteroids. The immunological implications of an unfavorable NLR, and whether corticosteroids might drive prostate cancer progression in patients harboring a high NLR, warrant further study.