MP70-17 OPTIMAL TESTOSTERONE SUPPRESSION ON MEDICAL ANDROGEN DEPRIVATION THERAPY SHOULD STRIVE TO SUPPRESS FREE TESTOSTERONE LEVELS, TO LEVELS SIMILAR TO ORCHIECTOMY--WHAT IS THAT VALUE?

Abstract

You have accessJournal of UrologyProstate Cancer: Advanced II1 Apr 2014MP70-17 OPTIMAL TESTOSTERONE SUPPRESSION ON MEDICAL ANDROGEN DEPRIVATION THERAPY SHOULD STRIVE TO SUPPRESS FREE TESTOSTERONE LEVELS, TO LEVELS SIMILAR TO ORCHIECTOMY--WHAT IS THAT VALUE? Evan Yu, Robert Getzenberg, Jordan Smith, Michael Hancock, Matthew Smith, S Bruce Malkowixz, Paul Sieber, James Dalton, and Mitchell Steiner Evan YuEvan Yu More articles by this author , Robert GetzenbergRobert Getzenberg More articles by this author , Jordan SmithJordan Smith More articles by this author , Michael HancockMichael Hancock More articles by this author , Matthew SmithMatthew Smith More articles by this author , S Bruce MalkowixzS Bruce Malkowixz More articles by this author , Paul SieberPaul Sieber More articles by this author , James DaltonJames Dalton More articles by this author , and Mitchell SteinerMitchell Steiner More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.2215AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The goal of medical androgen deprivation therapy (ADT) for advanced prostate cancer is to provide an equivalency to orchiectomy based upon older assays for serum testosterone. Literature shows that based on more modern assays, medical ADT does not always provide optimal testosterone suppression equivalent to orchiectomy. With the understanding that free, or unbound, testosterone is the biologically and clinically relevant component, the therapeutic goal of ADT should be to decrease free testosterone to levels similar to orchiectomy. Free testosterone has not been well studied in a substantial number of orchiectomized men. The purpose of this study was to examine a subpopulation of orchiectomized men in a clinical trial to determine the level of serum free testosterone in advanced prostate cancer. METHODS Baseline data was utilized from a double blind, randomized, placebo controlled trial (G300203) to determine the capacity of toremifene 80 mg to prevent bone fractures in men on ADT. This study included 1,389 men from 150 sites in the US and Mexico. Baseline characteristics, including whether men were on medical ADT or status post orchiectomy, were available. Serum free testosterone levels were assayed at baseline by radioimmunoassay (RIA) (Diagnostic Products Corporation) and are reported for men who underwent orchiectomy. RESULTS A subpopulation of 114 men underwent orchiectomy. Median age was 76 years (range 51-90). Median serum free testosterone level was 0.92 pg/ml (min. 0.35 pg/ml and max. 33.95 pg/ml) with a mean level of 1.71 pg/ml ± 2.77. CONCLUSIONS This study is believed to be the largest cohort in which serum free testosterone levels have been reported in men who underwent orchiectomy. In this cohort, median serum free testosterone is approximately 0.9 pg/ml. This value could be considered to be the optimal testosterone suppression of free testosterone with orchiectomy and represents the goal of medical ADT. At the time this study was performed, RIA was considered to be the standard but has since been shown to underestimate serum free testosterone levels by 20-60%. Currently, equilibrium dialysis coupled with LC-MS/MS is the gold standard, but the results from this analysis provide us with increased understanding of the optimal level of free testosterone in treating advanced prostate cancer. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e812 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Evan Yu More articles by this author Robert Getzenberg More articles by this author Jordan Smith More articles by this author Michael Hancock More articles by this author Matthew Smith More articles by this author S Bruce Malkowixz More articles by this author Paul Sieber More articles by this author James Dalton More articles by this author Mitchell Steiner More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...