Hormonal therapy for patients with advanced adenocarcinoma of the prostate: is there a role for discontinuing treatment after prolonged androgen suppression?

Abstract

Objectives To determine the hormonal (luteinizing hormone [LH], testosterone) and biochemical (prostate-specific antigen [PSA]) response to withdrawal of LH-releasing hormone (LHRH) agonist therapy for patients with prostate cancer with an undetectable PSA who received this treatment for an extended period. Methods Four selected patients older than 70 years of age with advanced adenocarcinoma of the prostate who were treated with a depot injection of LHRH and antiandrogen therapy had their treatment discontinued. During the period of total androgen blockade, each patient obtained and maintained a persistent undetectable PSA level. After cessation of androgen blockade, patients underwent serum measurements of PSA and testosterone at baseline and then every 6 months for 36 months. Serum LH was performed at baseline and then at 6, 18, and 36 months. Results At the time androgen ablative therapy was discontinued, patients had received LHRH agonist/antiandrogen therapy for a mean of 108 months (range 94 to 120). All 4 patients had castrate levels of testosterone (less than 0.5 ng/mL) and undetectable levels of PSA at baseline and with continued monitoring. At 6 and 18 months, all patients except one had LH levels in the normal range. All 4 patients remained clinically asymptomatic throughout the follow-up period with undetectable PSA levels. Conclusions Withdrawing hormonal therapy in asymptomatic patients with advanced prostate cancer after prolonged total androgen blockade was noted to be safe and effective in elderly patients who had achieved an undetectable PSA level. It appears that reduced testosterone levels may be a result of altered and potentially irreversible Leydig cell function rather than continued suppression of the hypothalamic-pituitary-testicular axis.