Objective: Evaluation of changes in mammographic and ultrasound image of the breast in women undergoing hormonal replacement therapy (HRT). Material and methods: 794 women with menopause, who had been undergoing hormonal replacement therapy (HRT) for 2-10 years, and the control population of 150 women with menopause not using HRT, were selected for the study. 618 women used combined HRT (an estrogen and a progestogen combination) and 176 women with surgical menopause used estrogen hormonal substitution (ERT). Changes in mammographic and ultrasound image were evaluated separately in the women's population with combined and estrogen hormonal replacement therapy and also in relation to the individual breast types according to Tabár's classification, with respect to the method of usage of the combination hormonal preparations (continual and cyclic), and route of administration of the hormone preparation (oral and intradermal). In 172women withHRT, the ultrasound image changes were monitored as well. Results: In menopausal women undergoing HRT, both groups showed a statistically significant increase in the density of themammographic image. It was more than twice as frequent in the group of women using combination HRT than in the group of women using estrogen monotherapy. In the group of women using combination as well as estrogen hormone replacement, an increased mammographic density was observed in a greater percentage of women with oral administration versus the women with intradermal administration of the hormonal preparation. A more significant increase in the mammographic density was observed in women using the combined hormone preparation continually, compared to the cyclically used replacement. The increase inmammographic density was more significant in the group of women using combination HRT as well as ERT, and more frequent in women with a breast type classified as Tabár's pattern II and III. Ultrasound examination in women undergoing HRT showed the presence of new, and the enlargement of previously present benign formations in the breast, twice as high in the group of women using estrogen monotherapy versus the group of women with combination hormone replacement therapy. In four women, a carcinoma was diagnosed during the use of hormonal replacement. Conclusion: In the groups of women undergoing combination as well as estrogen hormone replacement therapy, a statistically significant increase in mammographic density was observed. The increase in mammographic density was statistically significantly higher in the group of women using a combination hormonal preparation versus the group of women with estrogenmonotherapy, inwomen undergoing a combined hormone preparation continually,compared to the cyclically used replacement and in women with a predominance of adipose tissue in the breast.

        Key words: hormonal replacement therapy - density of mammographic image - ultrasound examination - Tabár's classification