Estradiol plus drospirenone therapy increases mammographic breast density in perimenopausal women

To investigate the effects of 17β-estradiol 1mg plus drospirenone 2mg (E2/DRSP) treatment on mammographic breast density in perimenopausal women.

In this prospective study, 80 healthy perimenopausal women aged 41-49 years were enrolled and assigned to either E2/DRSP (n=40) or a control group (n=40). Mammograms were performed at baseline and after 12 months of treatment. Mammographic breast density was quantified according to the Wolfe classification.

We demonstrated an increase in mammographic breast density in 37% (95% CI (confidence interval): 18.8-55.3%) of women treated with E2/DRSP after 12 months. The percentage of women with increased density was 0% (95% CI: 0.0-0.0%) in the control group. The difference in breast density between the E2/DRSP group and the control group was statistically very significant (p<0.001).

E2/DRSP therapy for 12 months in perimenopausal women significantly increased mammographic breast density in comparison to a control group. Further long-term and large scale prospective studies are needed to evaluate this issue.