1. Breast density is determined through a woman’s mammogram and described as one of four categories depending on the amount of breast tissue in comparison to fat in the breast.

2. 40% of women age 40 and over have dense breasts.

3. Cancer is 4-6 times more likely in women with extremely dense breasts than in women with fatty breasts.

4. Though mammograms find some cancers not seen on other screening tests, in dense breasts, mammograms will miss more than 50% of the cancers present.