What You Need to Know About Breast Density

By Christine Walsh, radiologist and lead breast specialist for Genesis Health Systems and Radiology Group

Heterogeneously dense breast tissue? Extremely dense breast tissue? What does it mean? If you had a mammogram recently, you were informed about your breast density in your results letter. But why is that important for you to know? At Genesis, we want to help you understand what this means and how it could impact your health.

What is Breast Density?

Breasts are made up of fatty tissue and glandular “breast” tissue. Every woman has a combination of these types of tissue in their breasts. When there is more glandular tissue than fatty tissue, then the breasts are considered dense. When there is more fatty tissue than glandular tissue, then the breasts are not dense.

How Common are Dense Breasts?

Having dense breasts is VERY common. In fact, half of women having mammograms have dense breasts. Your breast density is not something you can control and is a unique feature about you. Breast density can change over time and is affected by things such a weight loss or gain and hormone use. Breast density can only be determined by having a mammogram. How your breasts feel is not an accurate predictor of density. Whenever you have a mammogram, the radiologist looks at and reports the density of your breasts. This density is discussed in the mammography report and is also reported to the patient in a letter.

Breast Density’s Impact on Breast Cancer Risk

Breast density is one of the many factors that can play into breast cancer risk. If you have dense breasts, you have a somewhat increased risk of breast cancer, but it doesn’t mean you are going to get breast cancer or that you are even at high risk of getting breast cancer. Breast density is just one thing about you. Other factors that affect breast cancer risk are family history, lifestyle factors (such a smoking), genetic mutations, hormone use, and pregnancy and menstrual cycle history. At Genesis, we use the Tyrer-Cuzick model to calculate a patient’s lifetime risk of developing breast cancer. Any patient who comes in for a breast imaging exam fills out a detailed questionnaire. It goes through all the risk factors—family history, lifestyle factors, any known genetic mutation, hormone use—and combines that with the breast density from the mammogram to help us calculate the patient’s risk of developing breast cancer.

Recommendations for Women with Dense Breasts

The Radiology Group and Genesis Health System recommend that women with dense breasts should:

1. Receive an annual mammogram with 3D mammography

2. Discuss with a primary care provider regarding overall breast cancer risk to see if they qualify for, or desire, additional imaging or referral to a high-risk clinic or genetic counselor. Breast density is an important factor to be aware of, but it is not enough to put a woman at high risk. Be informed and know what your risk factors are. You cannot change your breast density, but you can be proactive in your breast health.

Click here to learn more about breast density.