Polyestradiol phosphate: a preliminary evaluation of its effect on breast carcinoma.

The effect of polyestradiol phosphate (Estradurin), a long-acting estrogen preparation given im, was assessed in 24 elderly postmenopausal patients with stage II or III primary or recurrent breast carcinoma. Although the drug has been available for many years, there has been no report in the literature of its use in treating breast carcinoma. The results of this study show that a total of 17 of 24 (70.8%) patients had evidence of tumor regression lasting a minimum of 3 months, while in 14 (58.3%) patients regression was maintained for greater than or equal to 6 months. Seven patients had complete (100%) tumor regression. Side effects were almost nonexistent and the agent has been shown to be effective, with good patient acceptability and guaranteed administration. It could be considered as an alternative to oral estrogen therapy where patient compliance is poor and gastrointestinal side effects are severe enough that patients often request a change of treatment.