Influence of different types of antiandrogens on luteinizing hormone-releasing hormone analogue-induced testosterone surge in patients with metastatic carcinoma of the prostate.

The long-term effect of the luteinizing hormone-releasing hormone analogue-induced initial testosterone surge in the treatment of patients with metastatic carcinoma of the prostate still is unknown. However, acute worsening of the disease has been reported in up to 10% of the patients. To prevent such tumor flare we investigated the endocrinological effects of different types of antiandrogens administered in addition to a luteinizing hormone-releasing hormone analogue. Patients with newly diagnosed metastatic prostate cancer were pre-treated with either the steroidal antiandrogen cyproterone acetate (6) or the nonsteroidal antiandrogen flutamide (5) for 1 week before the initial injection of the depot luteinizing hormone-releasing hormone analogue Zoladex. In another 5 patients flutamide was first given 24 hours before Zoladex therapy was started. Luteinizing hormone, testosterone and prostatic acid phosphatase during month 1 of luteinizing hormone-releasing hormone analogue therapy were compared to data obtained in 5 patients treated by Zoladex alone. Only pre-treatment with cyproterone acetate was capable of preventing the Zoladex-induced testosterone surge. However, both pre-treatment regimens with either cyproterone acetate or flutamide for 1 week prevented an initial increase in prostatic acid phosphatase beyond pre-treatment levels in all patients. In contrast, in 4 of 5 patients treated with Zoladex alone and in 2 of 5 pre-treated with flutamide for 1 day an initial increase in prostatic acid phosphatase beyond the pre-treatment values was seen. Our data indicate that pre-treatment with flutamide for only 1 day may not be sufficient to prevent a luteinizing hormone-releasing hormone analogue-induced tumor flare in all cases.