Testosterone kinetics in the first cycle of intermittent androgen deprivation (IAD) for men with localized or biochemical relapse (BR) of prostate cancer (PC)

Abstract

5134 Background: Patients (pts) with localized PC or BR treated with androgen deprivation therapy (ADT) eventually become androgen independent (AI) and die. We previously defined a model that correlates first cycle IAD PSA nadir and duration off treatment (OFF) with time to AI and death in 53 pts (abstract 5146 ASCO ’07). We now report data on a larger number of evaluable pts and include the analysis of testosterone (T) kinetics. Methods: Eligible pts had histologic diagnosis of PC, no evidence of metastasis by bone and CT scan, and at least 2 consecutive rising PSAs 2 weeks apart. Pts were treated with 9 months of leuprolide acetate and anti-androgen then ADT was stopped. Monthly PSA and T levels were tracked until PSA reached 1 ng/mL if prostate removed or 4 ng/mL if prostate intact, at which time ADT was resumed as before in a new cycle. Pts were treated until AI, defined as 2 rises in PSA while on ADT with castrate T levels (< 0.5 ng/mL). Results: 74 of 102 pts were evaluable for analysis. The previou...