PT  - JOURNAL ARTICLE
AU  - TAKEHISA ONISHI
AU  - TAKUJI SHIBAHARA
AU  - SATORU MASUI
AU  - YUSUKE SUGINO
AU  - SHINICHIRO HIGASHI
AU  - TAKESHI SASAKI
TI  - Efficacy of Ethinylestradiol Re-challenge for Metastatic Castration-resistant Prostate Cancer
DP  - 2016 Jun 01
TA  - Anticancer Research
PG  - 2999--3004
VI  - 36
IP  - 6
4099  - http://ar.iiarjournals.org/content/36/6/2999.short
4100  - http://ar.iiarjournals.org/content/36/6/2999.full
SO  - Anticancer Res2016 Jun 01; 36
AB  - Background: There has recently been renewed interest in the use of estrogens as a treatment strategy for castration-resistant prostate cancer (CRPC). The purpose of this study was to evaluate the feasibility and efficacy of ethinylestradiol re-challenge (re-EE) in the management of CRPC. Patients and Methods: Patients with metastatic CRPC who received re-EE after disease progression on prior EE and other therapy were retrospectively reviewed for prostate-specific antigen (PSA) response, PSA progression-free survival (P-PFS) and adverse events. Results: Thirty-six re-EE treatments were performed for 20 patients. PSA response to the initial EE treatment was observed in 14 (70%) patients. PSA response to re-EE was 33.3% in 36 re-EE treatments. The median P-PFS for patients treated with initial and re-EE was 7 months and 4 months, respectively. Interestingly, PSA response to re-EE was observed even in non-responders to initial EE, and those treated with multiple re-EE. No patients developed cardiovascular or thromboembolic events. Conclusion: Re-EE may be safely repeated several times and can lead to a prolonged disease control in selected patients. Re-challenge with EE appears to be a reasonable option worth considering for patients with metastatic CRPC.