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

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 pat...