Postmenopausal hormone therapy and mammographic breast density

Abstract Objective The aim of this study was to evaluate the effects of different types of hormone replacement therapy (HRT) on mammographic density. Materials and methods In a prospective 1-year study, 103 postmenopausal women were randomized to receive tibolone 2.5 mg/die, continuous conjugated equine estrogens 0.625 mg/die plus medroxyprogesterone acetate (MPA) 5 mg/die or placebo. Mammograms were performed at baseline and after 12 months of treatment. Mammographic density was quantified according to the Wolfe classification. Results After 12 months of HRT 16 of the 35 patients (45.1%) receiving continuous combined hormonal therapy showed an increase of breast density change in the Wolfe classification. After treatment with tibolone, an up grading in breast density, according to Wolfe's classification, was found in 2 of the 43 patients (2.3%). No changes were recorded in the 25 patients of the control group. The difference between the group treated with continuous combined hormonal therapy and the control group was highly significant ( p p  = 0.34). Discussion Continuous combination HRT may be more commonly associated with an increase of mammography density than tibolone treatment.