Menopausal hormone therapies: their effect on mammographic density and breast cancer risk.

Postmenopausal hormone therapy (HT) increases breast density, an effect that is rapidly reversed upon treatment discontinuation. Increased breast density is recognised to be a powerful risk factor for breast cancer. It is therefore important to know whether HT-induced changes in mammographic breast density can provide information about an individual's future risk of breast cancer; or whether an absence of any change in breast density following HT should be viewed as reassuring. Mammographic breast density therefore needs to be examined in further detail in order to better assess the risks of breast cancer in postmenopausal women and further individualize prescribing practices.