Sex hormones in breast disease.

Serum concentrations of oestradiol 17beta and progesterone were measured daily throughout one menstrual cycle in 32 normal women, 32 women with benign disease of the breast and 10 women with cancer of the breast. In normal women concentrations varied with age. Women with cysts had concentrations of oestradiol 17beta which were significantly higher than normal. In women with cancer the concentrations of oestradiol 17beta and progesterone were significantly higher than normal, but the difference was very small and much larger numbers of patients need to be studied. Concentrations of oestradiol 17beta and progesterone in postmenopausal women were consistently very low.