Testosterone recovery after prolonged androgen suppression in patients with prostate cancer.

PURPOSE: We prospectively examined the extent and timing of testosterone recovery in patients with prostate cancer treated with 2 years of androgen suppression. MATERIALS AND METHODS: A total of 153 patients with pT3N0M0 prostate cancer or positive margins after radical prostatectomy, or with prostate specific antigen relapse were treated with radiation to the prostate bed plus 2 years of androgen suppression as per a phase II study. Androgen suppression consisted of nilutamide for 4 weeks plus busereline acetate bimonthly for 2 years. Serum testosterone was measured at baseline, every 4 months during androgen suppression and every 6 months after androgen suppression during followup. Testosterone recovery to supracastrate levels, and to baseline and/or normal levels was estimated using Kaplan-Meier methods. Prognostic factors for testosterone recovery were examined. RESULTS: A total of 121 patients who completed 2 years of androgen suppression and 20 patients who received shorter durations of androgen suppression (median 16 months) were available for testosterone recovery analysis. Median followup after finishing androgen suppression was 38.9 months. All patients achieved castrate levels on androgen suppression. At 36 months after completion of androgen suppression 93.2% and 71.5% had recovery to supracastrate (median time 12.7 months), and to baseline and/or normal testosterone levels (median time 22.3 months), respectively. On multivariate analysis younger age (younger than 60 years, p = 0.0006) and shorter androgen suppression duration (less than 2 years, p = 0.028) were prognostic for faster recovery to baseline and/or normal testosterone levels after adjusting for baseline testosterone levels (p = 0.447). CONCLUSIONS: Testosterone recovery after prolonged androgen suppression is protracted. Older age and longer duration of androgen suppression result in significantly longer recovery times to baseline and/or normal testosterone levels.