PLASMA AND URINARY ESTROGENS IN BREAST-CANCER PATIENTS ON TREATMENT WITH 4-HYDROXYANDROSTENEDIONE

Plasma and urinary oestrogens were measured in nine breast cancer patients (eight postmenopausal women and one,man) before and during treatment with the aromatase inhibitor 4-hydroxyandrostenedione. Urinary oestrogens were measured by using a highly specific GC-MS method. Plasma levels of oestrone. oestradiol and oestrone sulphate were suppressed by 66.6% (+/- 3.6%), 57.7% (+/- 5.1%) and 51.8% (+/- 6.4%) respectively (P<0.005 for all). Twenty-four hour urinary excretion of total oestrogens, oestradiol, oestriol. 2-hydroxyoestrone, 16alpha-hydroxyoestrone and the minor metabolites 16beta - and 15alpha-hydroxyoestrone were all suppressed by mean values ranging from 60% to 82%, (oestradiol. P<0.025, otherwise P<0.005). There were no significant changes in the ratios between the different plasma oestrogens. The finding of sustained plasma and urinary oestrogens at 20-40% compared to their control levels indirectly support a hypothesis of alternative oestrogen sources in postmenopausal breast cancer patients on treatment with 4-hydroxyandrostenedione.