Mammographic changes related to different types of hormonal therapies

To determine the effects of different types of hormone therapies (HT) on mammographic breast density changes.

Between 1999 and 2002, mammograms obtained before and 12-18 months after different types of HT in 170 women were evaluated Estrogen alone (n = 66), or estrogen in cyclic (n = 59) or continuous (n = 45) combination with progesterone were used. The baseline mammographic density was classified according to the Breast Imaging Reporting and Data Systems (BI-RADS). The serial changes observed mammographically were categorized as follows; no change, minimal change (10-25% increased density), moderate change (26-50% increased density), and marked change (> 50% increased density).

Twelve (7%) of the women developed an increase in parenchymal density after HT: Mammographic changes were minimal change in five (2.9%) of the women, moderate change in four (2.3%), and marked change in three (1.8%). No mammographic change was observed in women receiving cyclic estrogen-progesterone. A greater percentage of women who had undergone continuous estrogen-progesterone therapy (22.2%, 10 of 45) demonstrated more change than those who had estrogen alone (3%, 2 of 66). The difference was statistically significant (p < 0.01).

Changes of increased density after HT was seen in only 7% of mammograms and depended on the selected hormone regimen.