PURPOSE: to measure changes and predictors of changes in mammographic density of climacteric women, before and one year after hormone replacement therapy. METHODS: seventy climacteric women of 45 years or more participated in the study. They were followed-up at a Climacteric Outpatient Service. All of them used regularly either estrogenic or estroprogestative HRT for one year. They were submitted to one basal mammography and another at the end of the first year. HRT schedules could be different from each other, although with the same bioequivalence. Mammographic density was evaluated blindly at the beginning and at the end of the treatment. Age, ovarian function, time since menopause, body mass index, waist/hip ratio, age at menarche, age at first pregnancy, and smoking were evaluated as well. Mammographic density was classified according to the American College of Radiology BI-RADS system into one of the following four parenchymal patterns: A) entirely liposubstituted breasts, B) liposubstituted breasts with disperse glandular parenchyma, C) heterogeneously dense breasts, and D) extremely dense breasts. We proposed a subdivision of each category in to A e A1, B e B1, C and C1, D and D1 in order to identify smaller variations in mammographic density. Therefore, we attributed initial and final scores of 1-8 to each of the patients according to the mammographic density before and after HRT, corresponding to categories A to D1. The proportions of women that presented increase, decrease and no variation in mammographic density after 1 year of HRT were calculated. In addition, we estimated initial to final score variation using the paired t-test of the Statistical Package for Social Sciences (SPSS). RESULTS: mammographic density increased in 22.9%, decreased in 7.1% and did not change in 70% of the studied cases. A significant difference was observed between the score means before (2.2±1.82) and after HRT (2.5±1.9) (p=0.019). The androgenic distribution of body fat was associated with a denser mammographic pattern. CONCLUSIONS: an increase in mammographic density was shown in women undergoing HRT, and was most pronounced in women with androgenic fat distribution. Additional studies must be carried out in order to evaluate if this increment in mammographic density could impair the mammographic screening of breast cancer.
Hormonal replacement therapy; Mammographic density; Mammographic parenchymal pattern
