Podcast: What Does It Mean to Have Dense Breasts?

When you get the results of your mammogram, you may also get a note. telling you that you have dense breasts. I'm Dr. Temeika Fairley. I'll explain what that means and why it’s important.

A woman's breast has three kinds of tissue: glandular tissue, which includes the part of the breast that makes milk called the lobes and the tubes that carry the milk to the nipple called ducts; fibrous tissue, which holds the breast tissue in place; and fatty tissue, which fills the space between the fibrous tissue, lobes and ducts. It gives the breast their size and shape. Breast density reflects the amount of fibrous and glandular tissue in a woman's breast compared to the amount of fatty tissue as seen on a mammogram.

In a mammography report, breast density is assigned to one of four categories: the breasts are almost entirely fatty, a few areas of dense tissue are scattered throughout the breast, the breasts are evenly dense throughout, or the breasts are extremely dense. Women in the first two categories are said to have fatty breasts. Women in the second two categories are said to have dense breasts. About half of women who are 40 or older have dense breasts.

Women with dense breasts have a higher chance of getting breast cancer. The more dense your breasts are, the higher your risk.

This mammogram shows a mostly fatty breast, and this mammogram shows a dense breast. Dense tissue can hide cancers. The fibrous and glandular tissue looks white on a mammogram and so does a possible tumor. Since it's hard to tell the difference between a tumor and dense breast tissue, a small tumor may be missed.

If you have dense breasts, talk to your doctor about your risk of getting breast cancer. Dense breasts are just one of several risk factors for breast cancer. Your doctor will also consider other factors like your age and family history of cancer.

Talk with your doctor about how often you should be screened and which tests are right for you.

To learn more, visit cdc.gov/cancer/.