Serum oestradiol-17 beta in women with benign and malignant breast disease.

Serum concentrations of oestradiol-17β were measured daily throughout one menstrual cycle in 32 normal women, 31 women with benign disease of the breast and 10 with cancer of the breast. The concentrations were found to differ significantly from normal in women with cysts and to a lesser extent in those with cancer of the breast. In 25 normal post-menopausal and in 27 post-menopausal women with cancer repeated assays disclosed consistently low levels of oestradiol-17β.