reduced time to development of castrate resistant prostate cancer and lower CSS. ... to androgen independent progression and defined as a rising PSA > 4 ... MP74-03. LOW FREE AND BIOAVAILABLE TESTOSTERONE LEVELS CAN.
THE JOURNAL OF UROLOGYâ
e856
PR7 was an international study comparing intermittent to continuous ADT which showed no difference in overall survival or prostate cancer mortality. The primary hypothesis was that, in the patients on continuous androgen deprivation, higher testosterone values correlate with a reduced time to development of castrate resistant prostate cancer and lower CSS. METHODS: This was an analysis of 626 patients on the continuous arm of the NCIC/SWOG/UKCCR PR7 study which randomized patients with biochemical failure after radiation or surgery plus radiation and no metastases between continuous life long androgen deprivation and intermittent androgen deprivation. Serum testosterone was assayed every 3 months. The relationship between the minimum, median, and maximum testosterone in the first year, and the time to androgen independent progression and defined as a rising PSA > 4 with testosterone < 3.0 nm/l was evaluated using Cox regression model. RESULTS: There was a significant difference among the 3 groups (p ¼ 0.009) in time to hormone resistance between those who had median testosterone between < 0.7, between 0.7 and 1.7, and 1.7 nmol/L, (< 20, 20-50, and 50 ng/d l) with median time to CRPC being not reached, 6.4, and 4.2 years for the 3 groups respectively. Patients with median T > 0.7 had a significantly higher risk of developing hormone resistance (HR 1.41 for serum T 0.7-1.7 (95% CI 1.071.84), and, HR 1.91 for T > 1.7 (95% CI 1.11-3.29). Maximum Testosterone > 0.7 (reflecting breakthrough) trended to more rapid progression to hormone resistance, but this did not achieve significance (P ¼0.17). Time from hormone resistance to prostate cancer death was shorter in those men with a higher median testosterone. CONCLUSIONS: This study demonstrates conclusively that low nadir serum testosterone on ADT < 0.7 mMol/L (< 20 ng/dl) correlates with improved duration of response to androgen deprivation in men on CAD being treated for biochemical failure. Serum Testosterone should be assayed regularly on such patients, and ADT modified to ensure levels < 0.7 are achieved.
Source of Funding: NCIC CTG, SWOG, UKCCR
MP74-02 FREE SERUM TESTOSTERONE VERSUS TOTAL TESTOSTERONE AS SURROGATE MARKER FOR THE CLINICAL BENEFIT OF ANDROGEN SUPPRESSION IN PROSTATE CANCER PATIENTS Lucas Regis*, Ignacio Iztueta, Pol Servian, Cristian Kosntantinidis, Jacques Planas, Ana Celma, Barcelona, Spain; Jose Placer, barcelona, Spain; Ines DeTorres, Juan Morote, Barcelona, Spain INTRODUCTION AND OBJECTIVES: Total testosterone (TT) serum levels have been related with the clinical benefit of androgen
Vol. 191, No. 4S, Supplement, Tuesday, May 20, 2014
suppression (AS) in prostate cancer (PC). However the active form of testosterone (FT) represents only 2% of TT while 40% is bound to SHBG and 58% to albumin. Our objective was to analyze if FT is a better surrogate marker than TT for clinical benefit of AS. METHODS: TT (chemiluminiscent assay-lower sensitivity 10 nd/dL) and FT (analoque ligand radioimmunoassay-lower smesitivity 0.05 pg/mL) were determined in 73 patients after 12 months of LHRH agonist. The mean follow up was 107 months (22-304). 36 patients (49.3%) developed castration resistence (CR), 15 patients (20.5%) metastatic spread and 6 patients (9.2%) died of PC. Cox regression analysis to predict survival free of CR including age, clinical stage, Gleason score, basal PSA, primary treatment, TT and FT was done. Survival analysis using 50, 32 and 20 ng/dL for TT, and 1.7, 1.1 and 0.7 pg/mL for FT was done in order to establish the castration level of FT with clinical impact. RESULTS: FT (OR: 4.33; 95%CI: 2.02-9.96), p
