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.

Abstract

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). 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. 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 C-reactive 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. 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.