Dense Breasts: 5 Facts You Should Know

After your mammogram, were you told you have dense breasts? This is how many women find out they have dense breasts.

Here are some facts about what it means to have dense breasts and what you might do.

• Breasts are made of fat and glands (that make milk) held together by fibrous tissue. The more glands and fibrous tissue a woman has, the “denser” her breast tissue.
• Many women have dense breasts. This is normal and common. In fact, almost half of all women over the age of 40 have dense breasts.
• When radiologists review (look closely at) mammograms, they can see how dense the breasts are. Below are four mammogram images of breasts. The glands appear as white. The two images on the right are referred to as dense breasts.
• Dense breasts make it harder for radiologists to see cancer on a mammogram.  Because of this, cancers are often larger when found in women with dense breasts. As you can see in the images at the bottom, dense breasts can sometimes “hide” cancer.
• Dense breasts are a risk factor for breast cancer. A woman’s risk for breast cancer increases with the level of density in her breast.

Four Categories of Breast Density. The two on the right (C and D) are referred to as “dense” breasts.

A) Fatty; (B) Scattered; (C) Heterogeneously dense; (D) Extremely dense

Dense Breasts Can Sometimes “Hide” Cancer.

On a mammogram, it can be hard to see cancer in a dense breast.  

Learn More: 

• Patient Fact Sheet (print)
• Patient Risk Checklist (print)
• Patient Questions and Answers
• Patient Video Series