Intermittent endocrine therapy for advanced prostate cancer.

Twenty patients with advanced prostate cancer have been treated with an intermittent endocrine therapy schedule. Hormone therapy (diethylstilbestrol in 19 patients and flutamide in 1 patient) was administered until a clinical response was clearly demonstrated and then it was withheld until symptoms recurred. Prior to treatment 17 of 20 patients had bone pain and positive radionuclide scans, two had asymptomatic pulmonary metastases, and one had symptomatic localized disease. Duration of endocrine therapy prior to withdrawal of all treatment ranged 2 to 70 months (median, 10 months). Disease progression occurred 1 to 24 months (median, 8 months) after interruption of therapy. All patients who relapsed had a rapid clinical response following resumption of endocrine therapy. Nine of ten patients rendered impotent by endocrine therapy resumed sexual activity within 3 months of stopping treatment. This data indicates that satisfactory palliation of advanced prostatic cancer can be achieved in selected patients using intermittent endocrine therapy.