Dense breast tissue: What it is, and what to do if you have it

Breasts come in all shapes and sizes, but did you know they can also vary in density? Breasts are composed of fat and glandular breast tissue, and the ratio of fat tissue to glandular breast tissue is what determines your breast density. Some women have less glandular breast tissue; this is referred to as not dense. Others have more glandular breast tissue, which means they have dense breast tissue.

When you have dense breast tissue, that can make it harder to spot breast cancer on a screening mammogram. That’s because glandular breast tissue and cancerous tissue are both white on mammograms. When you have a lot of normal white breast tissue, it makes it easier for small white tumors to hide.

50% of women have dense breast tissue, but it’s more common in young women, especially those with a lower body mass index. “Genetics, body mass index and age are some of the main drivers. So, if your mother or other close relative has dense breast tissue, you might, too,” says Ethan Cohen, M.D., a breast radiologist at MD Anderson West Houston. He adds that the breast tissue usually becomes less dense as you age.

“It’s important for women to know whether or not they have dense breast tissue,” Cohen says. That’s because denser breast tissue means that you might benefit from additional breast cancer screening.

Knowing about your breast density is the first step in getting the right screening exams to detect breast cancer early, when it’s easier to treat.

Screening mammography results identify dense breast tissue type

Depending on where you live, there may be laws in place to inform you of your breast density. Even if that’s not the case, Cohen says you can ask for your mammogram results to learn about your breast tissue.

MD Anderson patients can access this information via MyChart, but you can also ask your provider for details about your breast density.

Your imaging report will include one of four specific phrases about the density and composition of your breasts:

• “Almost entirely fatty.”
• “Scattered tissue” or “scattered areas of fibroglandular density.”
• “Heterogeneously dense.”
• “Extremely dense.”

If your results include one of the first two statements, your breasts aren’t dense and you should continue with an annual mammogram.

The last two statements mean you have dense breast tissue and may benefit from additional screening.

Additional screening options for dense breast tissue

The main screening options beyond a mammogram are breast ultrasound and MRI. Each of these additional tests requires orders from your doctor, unlike regular screening mammograms, which patients can schedule at any time.

Women with dense breast tissue at average risk for breast cancer may undergo an ultrasound of both breasts on the same day as their mammogram. “Ultrasound uses sound waves, rather than low-dose X-rays like mammography, to look through the breast tissue,” Cohen says. “So, they often find abnormal tissue that might not show up on a mammogram, which could help spot breast cancer earlier when it’s easier to treat.”

Recommendations for people at high risk for breast cancer

There are studies that suggest that women who have dense breast tissue are at slightly higher risk of breast cancer, but Cohen says the increase in risk is small compared to other risk factors like age and family history. “Average-risk women start out with a one in eight lifetime risk of breast cancer, and this increases slightly if they have dense breast tissue,” he says.

If you have dense breast tissue and are at an increased risk of breast cancer due to a genetic mutation or other factors, your care team may recommend alternating MRIs and mammograms every six months. “That way we’ll be sure to catch any abnormalities as early as possible,” Cohen says.

How dense breast tissue affects cancer treatment 

If you are diagnosed with breast cancer, you need to have additional screening MRIs or ultrasounds before beginning treatment, especially if you’re having surgery. “Your care team will want to know exactly where any cancerous tissue is, so they can target and remove it more precisely,” Cohen says.

If you have dense breast tissue, Cohen recommends seeking care from experts – no matter your breast cancer risk. “You want an imaging specialist who’s got experience with special screenings and understands normal results versus abnormal ones,” he says.

Schedule your breast screening at MD Anderson online or by calling 1-844-240-7092.