If you’ve ever been told you have dense breasts but left the doctor’s office confused, you’re not alone. Almost half of women over 40 have dense breast tissue, which can increase the risk of breast cancer.
However, many women are unsure of what that actually means or what to do about it. That’s changing. Starting this week, women with dense breasts will receive clearer guidance after a mammogram about their risks and next steps, thanks to a new FDA rule.
This new rule comes months after the U.S. Preventive Services Task Force (USPSTF) recommended that women begin getting mammograms every other year, starting at age 40—not starting at age 50, as th USPSTF previously suggested—and continuing until age 74.
How does breast density impact mammogram accuracy?
“Breast density is a measurement of fatty breast tissue, glandular tissue and fibrous tissue,” said Dr. Melissa D. Fana, a breast surgical oncologist at NYU Langone Health, in an interview with Flow Space. “Basically, the denser a woman’s breast is—which is determined by how it looks on a mammogram, not by how it feels—we can classify the breast tissue into categories of density.”
On a mammogram, dense tissue appears white, much like cancerous tissue, making it harder to detect abnormalities. Because of this, Fana said, understanding breast density is crucial for categorizing a woman’s breast tissue and assessing her cancer risk.
“By including breast density assessments on mammogram reports, we can inform the patient of their density, which can impact their risk, and make further recommendations for additional imaging if necessary,” she said.
The importance of early detection
Apart from skin cancer, breast cancer is the most common cancer among women in the U.S. According to the American Cancer Society (ACS) breast cancer accounts for about 30% of all new cancer cases women face each year.
For 2024, an estimated 310,720 new cases of invasive breast cancer will be diagnosed in women. The National Cancer Institute reports that women with dense breasts have a higher risk of breast cancer than those with more fatty breast tissue.
For women who undergo regular mammograms, the chances of early detection are higher, which reduces the need for more aggressive treatments, such as a mastectomy or chemotherapy, and significantly increases the likelihood of a successful outcome.
“We know that mammograms are the gold standard for breast screening and are proven to decrease mortality, which is why almost every patient will begin with a screening mammogram,” said Dr. Jennifer Chen, the lead breast imager at City of Hope Orange County in Irvine, California. “A breast ultrasound is helpful for distinguishing a benign, fluid-filled cyst from a solid mass.”
When to consider an ultrasound or MRI
Chen noted that sometimes an ultrasound can detect abnormalities too small to be seen on a mammogram, such as early cancers or benign cysts. As a breast imaging specialist, Chen uses ultrasounds to focus on a specific area of concern and to determine if a lump is a benign cyst or a solid mass that requires further investigation.
“However, a breast ultrasound cannot detect microcalcifications, which can be a sign of early breast cancer,” Chen said. “Ultrasounds and MRIs can be useful for individuals with dense breasts, but they should not be used as a substitute for a mammogram.”
Dr. Anne Peled, a plastic surgeon specializing in reconstructive surgery for breast cancer patients, also advises conducting a comprehensive breast cancer risk assessment. This should include factors such as family history, previous abnormal breast biopsies and other gynecological factors to determine if additional risk reduction measures could be beneficial based on a person’s calculated lifetime risk of breast cancer.
“Breast density is categorized into four groups—if you fall into the heterogeneously or very dense categories, you may have an increased risk of cancer and/or more difficulty detecting cancers on mammograms in the future,” Peled said.
Looking ahead
If you receive these results, Peled recommends speaking with the provider who ordered your mammogram to determine if additional screening would be helpful. The FDA’s new rules are designed to simplify medical language, making it easier to understand, especially for those with low health literacy.
The rules will explain what breast density means and provide clearer guidance on when to consult a doctor for more information. Breast density will be categorized into four levels, with a detailed explanation of the risks associated with each one.
According to Fana, costs may be affected if insurance companies start requiring evidence-based referrals for ultrasounds based on breast density, but it’s still too early to tell.
“The new guidelines from the FDA on informing patients of their breast density on mammograms are very encouraging. We’ll be better informed, receive more appropriate screening when necessary and ultimately save lives,” Fana said. “These changes show that healthcare is evolving to include more personalized care.”