Therapeutic Effect of Ethinylestradiol in Castration-resistant Prostate Cancer

Background/Aim: The best sequential treatment for castration-resistant prostate cancer (CRPC) remains unclear. This study evaluated the therapeutic effects of ethinylestradiol (EE) on CRPC. Patients and Methods: A total of 80 patients with CRPC, treated with 0.5-1.5 mg/day of EE, were retrospectively assessed. Results: The median duration from the initial treatment to the beginning of EE was 48.3 months. A decline in the prostate-specific antigen (PSA) from the baseline was noted in 60 patients (75%) and a >50% PSA decline in 27 patients (34%). The median time of PSA progression, overall survival, and cancer-specific survival after EE were 5.60 months, 24.00 months, and 27.93 months, respectively. Conclusion: EE administration for CRPC showed a relatively high PSA response regardless of timing of sequential treatment. The frequency of cardiovascular adverse events was not significantly high. EE administration is a potential treatment option for CRPC.