Women with high breast density (as seen on a mammogram) are four to five times more likely to get breast cancer than women with low breast density.

How do health care providers use breast density?

At this time, health care providers do not routinely use a woman's breast density to assess her breast cancer risk. This is mainly due to the lack of a standard measure of breast density. While a measure of breast density may be recorded on a mammography report, this measure is not used to assess risk. However, by looking at your mammogram or the measure of breast density, your provider may conclude that you have dense breasts and may suggest other types of breast screening.

Some states in the U.S. now have laws requiring that mammography reports include whether or not women have dense breasts. Although it seems like including this information should be helpful, currently there are no special recommendations or screening guidelines for women with dense breasts. In addition, although women with dense breasts appear to be at higher risk of breast cancer, it is not clear that lowering breast density will decrease risk. For example, getting older and gaining weight after menopause are both related to a decrease in breast density, but are also related to an increase in breast cancer risk.