Ra-223 and Ethinylestradiol Combination Therapy in Castration-resistant Prostate Cancer

Abstract

Background/Aim: Ra-223 is a therapeutic agent for bone metastatic castration-resistant prostate cancer (mCRPC). We examined the efficacy of a treatment method using Ra-223 together with ethinylestradiol (EE). Patients and Methods: Patients who received Ra-223 three or more times were included and two groups (with or without EE) were compared retrospectively. Results: Eighteen patients were treated with Ra-223 and EE concomitantly (EstRadium therapy) and 13 patients were treated with Ra-223 alone or Ra-223 and agents other than EE (non-EstRadium therapy). The number of patients with decreased serum prostate-specific antigen level was significantly higher in the EstRadium therapy group than in the non-EstRadium therapy group (p=0.029). Conclusion: The combination of Ra-223 and EE, compared to Ra-223 alone, is an effective treatment option for bone mCRPC patients, in terms of PSA response.