Corticosteroid-induced inhibition of adrenal androgen production in selected patients with prostate cancer

To determine the effect of administration of corticosteroids on adrenal androgen production and the serologic markers of prostate cancer. Six patients with prostate cancer who had a serum testosterone concentration that exceeded 20 ng/dL despite treatment with medical or surgical castration were treated with dexamethasone. All patients were asymptomatic, but four were demonstrating progressive increases in serum prostate-specific antigen (PSA) concentrations. Dexamethasone, 1 mg at bedtime, was given initially and then increased to 1 mg twice daily if serum testosterone concentrations remained > or =10 ng/dL. The effect of treatment on PSA concentration was monitored. The mean testosterone concentration (and standard error of the mean) was 47.5 +/- 7.9 ng/dL before administration of dexamethasone; this decreased to 5.2 +/- 3.0 ng/dL during therapy (P = 0.002). The effect was rapid (overnight) and sustainable (for 6 months). Although the duration of follow-up is limited, PSA concentrations generally stabilized (23.5 +/- 6.1 ng/mL at baseline in comparison with 15.6 +/- 1.1 ng/mL approximately 2 months after initiation of dexamethasone therapy; P = 0.24). Two patients required 1 mg of dexamethasone twice daily to suppress serum testosterone levels to