Recent studies have indicated that conventional hormonal replacement therapy (HRT) is associated with an increase in breast density. The aim of this non randomised prospective study was to evaluate the effects of HRT and Tibolone on breast density in postmenopausal women.
The study population included 41 healthy women, who were on different HRT regimens and completed their 5-year mammographic follow-up. Before starting HRT, a baseline mammography was performed and repeated at 12-month interval during the follow-up. The patients, 41 healthy postmenopausal women, received 2 different treatments: continuous transdermal estrogen 50 microg/day plus sequential MPA 10 mg/day for 12 days at cycle (21 patients), Tibolone 2.5 mg/day (20 patients).
An increase in breast density was present in 25% of women receiving estrogen plus MPA. There was no mammographic breast density increase in Tibolone group; 9.5% of women receiving Tibolone showed reduced breast density. The modifications of breast density were reported during the 1st year of therapy.
These findings show that different HRT regimens have different effects on breast density. Tibolone does not significantly affect breast density, so it may be a preferable therapy for a larger group of postmenopausal women, including those with a familiar history of breast cancer and those with breast density.