Single drug polyestradiol phosphate therapy in prostatic cancer

Serum concentrations of testosterone (T) and estradiol-17 beta (E2) were analyzed in prostatic cancer patients treated with 160, 240, or 320 mg polyestradiol phosphate (PEP) i.m. every fourth week as single drug therapy during a 6 month period. Estrogen effects on the liver were studied by analyzing serum levels of sex hormone binding globulin (SHBG) in the 320 mg group and compared with values obtained in patients treated with 80 mg PEP i.m. every fourth week + oral ethinylestradiol (EE2) 150 micrograms daily, or by orchidectomy. Orchidectomy levels of T were reached within 3 weeks in the 320 and 3 months in the 240 mg group. In the 160 mg group, mean T levels reached the upper limit of orchidectomy values after 6 months. Accumulation of E2 occurred to mean levels 1,300-2,500 pmol/L at 6 months. At 6 months, SHBG levels had increased to 617% of pretreatment values in the oral EE2 group, to 166% in the 320 mg group, and were unaffected by orchidectomy. No cardiovascular side effects occurred during single-drug PEP treatment.