Plasma estrone-sulfate: assessment of reduced estrogen production during treatment of metastatic breast carcinoma.

Highly sensitive and specific estrogen assays are required to monitor the hormonal effects of surgical adrenalectomy or pharmacologic estrogen suppression in postmenopausal women with breast carcinoma. Because the levels of plasma estrone-sulfate are 10-fold higher than its unconjugated counterpart, we developed a radioimmunoassay for estrone-sulfate to quantitate the minimal estrogen concentrations expected under conditions of endocrine gland ablation. After establishing normal ranges, we compared plasma estrone- sulfate levels and urinary conjugated estrone basally and after surgical adrenalectomy or aminoglutethimide (estrogen suppression) therapy in 23 postmenopausal women with breast carcinoma. In response to either therapy, the plasma levels of estrone-sulfate fell by 63.5-79.2% (p less than .01) and conjugated urinary estrone by 85-94.5% (p less than .01) in all study days over a 12-week period. Correlation analyses yielded r values of 0.77-0.94 between conjugated plasma and urinary estrone concentrations in the surgical adrenalectomy and aminoglutethimide-treated groups, respectively. No significant differences in estrone-sulfate levels were observed when comparing spontaneously menopausal and surgically castrate patients.