MP22-04 INVESTIGATING THE IMPACT OF A LOWER TESTOSTERONE THRESHOLD ON CASTRATION-RESISTANT PROGRESSION IN PATIENTS ON CONTINUOUS ANDROGEN DEPRIVATION THERAPY

You have accessJournal of UrologyProstate Cancer: Advanced (including Drug Therapy) II (MP22)1 Apr 2019MP22-04 INVESTIGATING THE IMPACT OF A LOWER TESTOSTERONE THRESHOLD ON CASTRATION-RESISTANT PROGRESSION IN PATIENTS ON CONTINUOUS ANDROGEN DEPRIVATION THERAPY Maylynn Ding*, Taehyoung Lee, Richard Di Lena, and Bobby Shayegan Maylynn Ding*Maylynn Ding* More articles by this author , Taehyoung LeeTaehyoung Lee More articles by this author , Richard Di LenaRichard Di Lena More articles by this author , and Bobby ShayeganBobby Shayegan More articles by this author View All Author Informationhttps://doi.org/10.1097/01.JU.0000555588.43900.cfAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVES: Androgen deprivation therapy (ADT) is a first-line treatment for advanced prostate cancer and an adjuvant for localized treatment of high-risk disease. There is debate regarding optimal medical castration levels. We aimed to determine if a lower testosterone level below the previously accepted castration level of <50ng/dL has an impact on time to progression to castration-resistant prostate cancer (CRPC) in patients on continuous ADT. METHODS: This is a single-center, retrospective review of prospectively collected data on 156 consecutive patients who initiated continuous ADT at a tertiary centre from 2006 to 2017. Serum prostate-specific antigen (PSA) and testosterone levels were routinely assessed every 3 months after initiation of ADT. Patients were stratified based on absolute testosterone levels measured at 6 and 9 months following ADT initiation. Progression to CRPC was assessed using the Kaplan-Meier method and compared with the log-rank analysis. RESULTS: A total of 116 patients were included in the study. There were no baseline differences in age and pre-treatment PSA levels between groups. Median follow-up was 48 months (IQR: 30.5, 62.5). 41.4% of all patients were CRPC free at the date of last follow-up. In this study cohort, 71.6% of patients achieved a one-year mean testosterone level <20ng/dL; 21.6% achieved 20-32ng/dL; 3.4% achieved 32-50 ng/dL; and 3.4% achieved ≥50ng/dL. Patients who achieved an absolute testosterone level of <20ng/dL at 6 months had a significantly increased time to CRPC (log-rank p=0.025, median CRPC-free survival of 48 months [<20ng/dL] versus 24 months [≥20 ng/dL]). Likewise, patients with a 9-month absolute testosterone level <20ng/dL had a significantly increased time to CRPC (log-rank p=0.039, median CRPC-free survival 48 months [<20ng/dL] versus 20 months [≥20ng/dL]). CONCLUSIONS: Our study results support that strict testosterone control of <20ng/dL in patients undergoing continuous ADT will lead to longer progression free survival. In this series, only a small proportion of patients had one-year mean testosterone levels of ≥32ng/dL (6.9%). A multi-centre prospective study is needed to validate these findings. Source of Funding: None Hamilton, Canada; New York, NY; Hamilton, Canada© 2019 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 201Issue Supplement 4April 2019Page: e317-e318 Advertisement Copyright & Permissions© 2019 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maylynn Ding* More articles by this author Taehyoung Lee More articles by this author Richard Di Lena More articles by this author Bobby Shayegan More articles by this author Expand All Advertisement PDF downloadLoading ...