Mammographic density increase in women receiving different hormone replacement regimens

Objective: we investigated effects of different regimens of hormone replace ment therapy (HRT) on mammographic density. Methods: ninety-five postmenopa usal women, who were on different HRT regimens and completed their 4-year m ammographic follow-up. were included into this retrospective and comparativ e study. Twenty-three of these women, who had surgical menopause, received conjugated equine estrogens (CEE) (Group 1) only. 26 of them received CEE a nd continuous medroxyprogesterone acetate (MPA) (Group II). 21 women receiv ed CEE and cyclic MPA (Group III). and the remaining 25 women received tibo lone (Group IV) therapy, Before commencing on HRT, a baseline high-resoluti on mammography was performed, and repeated at 6-12-month intervals during t he period of 4-year follow-up. All mammographies were evaluated according t o the Wolfe classification. Results: a diffuse increase in mammographic den sity was detected in five women (22%) in group 1. nine women (35%) in group II. four women (19%,) in group III, and two women in group IV. The increas e in mammographic density was more common among women in group Il than thos e in the other three groups. However. a statistically significant differenc e was found only between groups II and IV, Conclusions: different HRT regim ens have different effects on breast parenchymal density on mammography. Co ntinuous combination HRT may be more commonly associated with an increase i n breast density than other forms of HRT. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.