OBJECTIVETo investigate the effects of long-term hormone replacement therapy (HRT) on the breasts of postmenopausal women using mammary ultrasonography.

METHODSAn open randomized clinical study was designed. The percutaneous estradiol gel was used in a cyclic regimen combined with micronized progesterone (MP) or medroxyprogesterone acetate (MPA). Sixty healthy women (natural menopause for 1 to 5 years) were recruited and divided into four groups according to the dosage of estrogen and two kinds of progestin. All were given for 25 days per month. Mammary ultrasonography was used to observe breast glandular section thickness, breast duct width, the morphology of lobular unit and the blood flow of color Doppler imaging at baseline and every year from the second to seventh year of HRT. The serum estradiol was also measured from the 15th to 25th day of the cycle. Breast pain was recorded by the subjects.

RESULTS(1) The breast glandular section thickness after HRT was larger than that of before HRT. The breast glandular section thickness became larger gradually over time while the breast duct width became smaller over time. The breast duct width of the fifth year of HRT was significantly different from that of the sixth year (P < 0.05). (2) Twenty-two persons had new breast structure changes after HRT, and the accumulated incidence was 41.5%. New solid lesions formation occurred in five subjects (8.3%) and new cyst formation occurred in one subject (1.7%). After the second year of HRT, the serum estradiol level of the subjects with breast structure changes was higher than that of without breast structure changes and in the sixth year of HRT, and the difference was significant (P < 0.05). After the second year of HRT, the breast glandular section thickness of the subjects with breast structure changes was larger than that of without breast structure changes and in the fifth and sixth year of HRT, the difference was significant (P < 0.05). (3) After HRT, the serum estradiol level of subjects with mastalgia was higher than that of without mastalgia and in the second and sixth follow-up year, the difference was significant (P < 0.05).

CONCLUSIONSThere is an increasing trend of the percentage of glandular tissues of the breast after HRT. There is an increasing trend of the serum estradiol level and the breast glandular section thickness among the subjects with the breast structure changes; there is an increasing trend of the serum estradiol level among the subjects with mastalgia. Mammary ultrasonography can be used to monitor breast structure changes and breast lesions during HRT.