Dense Breasts? Here’s What You Need to Know

Why do I need to know my breast density?

There are a few different reasons why breast density is important.

For starters, dense breast tissue can make it more difficult to detect cancer on a mammogram. Fibrous and glandular tissue appears white on a mammogram — but so does a possible tumor. “So [that] can make it harder for radiologists to visualize an abnormality,” says Tari A. King, M.D., chief of breast surgery at Dana-Farber/Brigham and Women’s Cancer Center in Boston.

Beyond this masking effect, women with what King calls extremely dense breasts are at increased risk for breast cancer, though scientists are not sure why, the Centers for Disease Control and Prevention (CDC) notes.

What can you do if you have dense breasts?

So, you just found out you have dense breasts. That doesn’t necessarily mean you need additional screening and added worry, King says. What it does mean is that you should have a conversation with your doctor, who will consider your overall breast cancer risk and, based on that risk, may recommend more imaging with an ultrasound or MRI.

These tests do not have the same masking effects as a mammogram, but they may lead to more false positives and unnecessary biopsies and they can be more expensive, King says. Patients with Medicare Part B can expect to pay 20 percent coinsurance for a breast ultrasound if their doctor deems it necessary. People with Medicare Advantage plans may need pre-authorizations or other information from a provider to show an additional test is medically necessary.

“There’s not a one-size-fits-all approach when it comes to recommendations for additional imaging,” King says.

Having dense breasts is one risk factor for breast cancer on a list of several. Others include age (most breast cancers are diagnosed after the age of 50, the CDC says) and a family history of breast or ovarian cancer. Physical inactivity and alcohol use play a role in the risk, as well.

“We also know that postmenopausal weight gain is a very significant risk factor for breast cancer, and so women should be really counseled about maintaining the appropriate body weight as they go through menopause,” King says.

Knowing all your risk factors, including your breast density, “is a really important step forward for patients to be proactive” in their breast health care, Kalambo says.

Also important: Bringing any breast abnormality to your doctor’s attention, even if your mammogram or other imaging tests are clear.

“Mammograms are excellent tools, but they are not perfect, even in women who don’t have dense breasts. And so don’t take a negative mammogram as reassurance. If you are concerned about something, still bring that to your physician’s attention,” King says.

Editor’s note: This story, first published April 5, 2023, has been updated.