Red Cell Distribution Width Predicts Prostate-Specific Antigen Response and Survival of Patients With Castration-Resistant Prostate Cancer Treated With Androgen Receptor Axis-Targeted Agents

The predictive value of pretherapeutic red cell distribution width (RDW) was retrospectively evaluated in castration-resistant prostate cancer treated with androgen receptor axis targeted agents. High RDW was an independent predictor of lower prostate-specific antigen (PSA) response and shorter PSA progression-free and overall survival. The evaluation of RDW might be useful for risk stratification among these patients. Purpose: To identify the impact of red cell distribution width (RDW) on treatment outcomes in patients with castration-resistant prostate cancer (CRPC) treated with androgen receptor axis-targeted agents (ARATs). Patients and Methods: Baseline data were obtained from 153 patients with CRPC treated with ARATs. Patients were stratified according to the upper limit of the normal RDW range, measured within 1 month before starting treatment. Relationships between RDW levels and the best prostate-specific antigen (PSA) response, PSA progression-free survival, and overall survival were examined. Results: Forty-nine patients were treated with abiraterone acetate in combination with corticosteroid and 104 with enzalutamide. The median RDW was 13.7% (interquartile range, 13.0 - 14.9). High RDW was significantly associated with prior use of docetaxel (P < .001), presence of lymph node metastasis (P = .031), presence of visceral metastasis (P = .001), and low hemoglobin (P < .001), low albumin (P = .016), and high Creactive protein levels (P = .02). In a multiple linear regression model, there was a statistically significant negative association between RDW levels and the best PSA response (P = .046). In addition, multivariate Cox regression analyses showed that high RDW was an independent predictor of both shorter PSA progression-free survival (hazard ratio = - 1.84; 95% confidence interval, 1.04-3.27; P = .037) and overall survival (hazard ratio = 2.62; 95% confidence interval, 1.15-5.98; P = .022), showing statistical significance. Conclusion: High RDW is an independent predictor of worse treatment outcomes in patients with CRPC treated with ARATs. RDW could be a readily available and inexpensive biomarker for predicting primary resistance to ARATs. (C) 2019 Elsevier Inc. All rights reserved.