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.

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 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.

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.