INFLUENCE OF TREATMENT WITH THE ANTIESTROGEN 3-HYDROXYTAMOXIFEN (DROLOXIFENE) ON PLASMA SEX-HORMONE LEVELS IN POSTMENOPAUSAL PATIENTS WITH BREAST-CANCER

Plasma levels of oestradiol (Oe(2)), oestrone (Oe(1)), oestrone sulpha te (Oe(1)S), androstenedione, testosterone, dehydroepiandrosterone (DH EA), dehydroepiandrosterone sulphate (DHEAS), sex hormone-binding glob ulin (SHBG) and the gonadotrophins (FSH and LH) were determined in 20 postmenopausal women with breast cancer treated with the anti-oestroge n droloxifene (3-hydroxytamoxifen). Plasma oestrogens were measured be fore and after 3, 6 and 12 months of therapy. The other hormones were measured before and after 6 months of therapy. Droloxifene treatment h ad no significant influence on plasma levels of Oe(2). Plasma levels o f Oe(1) and Oe(1)S increased during treatment (mean increase of 11.9-1 5.9% and 24.5-69.4% respectively after different time-intervals on tre atment). The Oe(1)S/Oe(1) and Oe(1)S/Oe(2) ratios increased by mean va lues of 13.8-45.2% and 25.9-52.4% respectively. Plasma SHBG increased significantly by a mean value of 73.9%, while FSH and LH fell non-sign ificantly by 19.7% and 20.4% respectively. Plasma levels of testostero ne, androstenedione, DHEA and DHEAS all increased during treatment, bu t none of these alterations were of statistical significance. While th e influence of droloxifene on plasma SHBG resembled that which is seen during treatment with tamoxifen, its influence on plasma oestrogens a nd the gonadotrophins seems to be different. Possible explanations of such differences and the clinical implications of alterations in plasm a hormones during treatment with droloxifene are discussed.