U.K. trials of treatment for M1 prostatic cancer. The LH-RH analogue Zoladex vs. orchidectomy.

A randomized, controlled trial of the treatment of metastatic prostatic cancer using either the LH-RH analogue Zoladex or orchidectomy is reported. The trial was conducted in the U.K. and Ireland and involved participants in 17 centers. The design of the trial is outlined and the response criteria discussed. The results show that the patient characteristics in the two treatment groups were comparable upon entry. Repeated administration of Zoladex every 28 days has been shown to be as effective as orchidectomy in lowering serum testosterone to castrate levels. The subjective and objective response rates were similar, as were the duration of response, time to treatment failure, and survival rates. The withdrawals from the trial and adverse reactions are discussed. These results, 10 months after the closure of recruitment to the trial, seem to indicate that Zoladex and orchidectomy are equivalent treatments and that Zoladex seems to be a truly medical alternative to surgical castration. Finally, other ongoing U.K. trials of the treatment of advanced prostate cancer are outlined.