RESUMO
OBJECTIVE: To determine the effect of administration of corticosteroids on adrenal androgen production and the serologic markers of prostate cancer. METHODS: 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. RESULTS: 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 <10 ng/dL. CONCLUSION: Administration of corticosteroids in a manner opposing the normal circadian glucocorticoid production effectively and rapidly decreases adrenal androgen production in patients with prostate cancer treated with orchiectomy or luteinizing hormone-releasing hormone agonists. This reduction of androgen production was generally associated with a decrease or stabilization of PSA concentrations in all patients with increased PSA levels. Overnight dexamethasone suppression testing is useful in determining the minimal effective dose.
