EORTC protocol 30853: orchidectomy versus zoladex plus flutamide in the management of metastatic carcinoma of the prostate. Interim statistical analysis of the side effects of treatment.

The toxicity and side effects of combination therapy with zoladex and flutamide have not been excessive compared with those due to orchidectomy. Pain due to the flare phenomenon has not been observed with zoladex and flutamide. Treatment modification has been necessary in 12 of the 149 patients receiving the combination therapy, compared with one of 148 patients who had surgical castration. Only one patient had flutamide withdrawn because of diarrhea and only five patients had treatment modification because of liver toxicity.