[Chemical castration using a depot LHRH-agonist as a palliative therapy concept in prostatic carcinoma--clinical,...

79 patients with locally advanced and/or metastatic prostate cancer were treated by means of a biodegradeable depot formulation of the luteinizing hormone releasing hormone analogue Goserelin (Zoladex). All patients received 3.6 mg depot Goserelin (Zoladex 3.6 mg implantate) subcutaneously into the anterior abdominal wall at 4 weekly intervals. The average time of observation was 24.2 months. The best objective response rate was found in 62%. Serum testosterone levels initially increased after the first depot injection and then decreased ultimately to castrate range (less than 0.6 ng/ml) between day 15 and day 27 (median 21) in the majority of patients. Castrate testosterone levels were still found 48 months after the start of treatment with depot Goserelin. 6 months after institution of treatment in 66.7% of cases evident signs of histological regression were found in the primary tumour tissue. Adenocarcinoma presented with a highly significantly better response pattern than anaplastic carcinoma. In animal experiments a single dose of 1 mg depot Goserelin was administered to adult male rats and the effect on serum testosterone levels and target organs (testes and ventral prostate) were investigated. Mean testosterone levels (mean = 0.31 ng/ml) decreased to castrate range (less than 0.3 ng/ml). 4 weeks after depot injection weight of the testes and prostate weight were significantly reduced. However 8 weeks after administration of 1 mg depot Goserelin there was no significant between the control group and the treated group. We conclude that the depot formulation of Goserelin (Zoladex) is effective, simple, practicable and safe in the treatment of advanced prostatic cancer. Current clinical studies are confirming the importance of reversible medical castration by LHRH agonists before radical prostatectomy.