Treatment of prostatic cancer by monthly injections of an LHRH-analogue depot.

Thirty-six patients with advanced prostatic cancer were treated by monthly depot injections of a luteinizing-hormone releasing hormone analogue (LHRH-a). Five of these patients were also pretreated for 14 days with cyproterone acetate (CPA) in order to counteract initial increase in testosterone concentration. Two weeks after the initial depot injection the serum testosterone had been reduced to and was maintained at castrate level. Luteinizing hormone and follicle stimulating hormone were also significantly reduced. Of the 31 patients 23 showed objective regression at 3 months, 9 had stable disease and none showed progression. At 3 months 22 patients reported subjective improvement. At 12 months 18 showed objective regression, 7 had withdrawn from therapy and 6 showed progression. Side effects were acceptable and comparable to those following surgical castration. It is shown that CPA counteracts the initial increase in testosterone concentration at initiation of LHRH-a treatment. We conclude that depot preparations of LHRH-analogues, both with and without pretreatment with CPA, are useful in the treatment of patients with advanced prostatic cancer.