Women will soon be informed about their breast density after a mammogram. This means that

Dense breasts can increase a woman’s risk of breast cancer and make it harder to detect cancer on a mammogram, but many are unaware that this is a significant risk.

Starting this week, all mammogram reports and letters sent to patients in the United States must include a breast density assessment. The U.S. Food and Drug Administration’s final rule requiring mammography facilities to inform patients about the density of their breasts takes effect Tuesday.

Breast density is a measure of how much fibroglandular tissue there is compared to fat tissue in a woman’s breast. The more fibroglandular tissue there is, the denser the breast.

About half of all women over 40 in the United States have dense breast tissue, said radiologist Dr. Kimberly Feigin, interim chief of the Breast Imaging Service and director of Breast Imaging Quality Assurance at Memorial Sloan Kettering Cancer Center.

“We talk about breast density for two reasons. First, breast density can make it harder to detect cancer on a mammogram because dense breast tissue – the glandular elements and the supporting elements of connective tissue – appears white on a mammogram, and cancer also appears white on a mammogram,” Feigin said.

In other words, dense breast tissue can hide cancer on a mammogram because the tissue appears white on a mammogram, the same way lumps and tumors appear.

“The second reason breast density is important is because dense breast tissue increases a woman’s risk of breast cancer,” Feigin said.

The new reporting requirements do not provide specific next steps for patients with dense breast tissue, but recommend that women talk to their doctor to better assess their individual risk and determine a screening plan that is appropriate for them.

Although mammography is recommended for all women over age 40, some women with dense breasts may benefit from additional breast imaging tests, such as ultrasound or MRI.

JoAnn Pushkin, 64, a breast cancer survivor who has been advocating for more than a decade to require women nationwide to report their breast density, said the new rule is long overdue.

In her mid-40s, Pushkin noticed a lump in her breast, but wasn’t too worried. About eight weeks earlier, she had had a mammogram that had returned normal results.

Nevertheless, she went for another mammogram, and the X-ray technician told Pushkin, “We didn’t see anything.”

Pushkin thought the technician had confused her with another patient.

“It was a big facility with multiple waiting rooms, and I just assumed she had come back to the wrong room,” Pushkin said. “I said, ‘Oh no, I’m the lady with the lump that was so big I could feel it.’ And she told me, ‘Oh, you have dense breasts. This is going to be a very difficult discovery for us.’ And I remember sitting back and saying to her, ‘Wait, what?’ I didn’t even know what to do with that sentence.”

Although Pushkin’s mammogram at the time did not show the lump she felt, she underwent further tests and had an ultrasound of her breast.

“And there was the lump, clear as a bell,” Pushkin said. “It was determined to be breast cancer. Within 20 minutes, I learned I had dense breasts, I learned I had breast cancer, and I learned it had been missed because I had dense breasts.”

Pushkin was diagnosed with the disease at a later stage and said she underwent eight surgeries and eight chemotherapy treatments as part of her treatment.

“A few years later, I relapsed and had to go through 30 radiation treatments. Now I have lymphedema, and it’s all because it wasn’t discovered until this late stage,” said Pushkin, who has testified before the FDA about breast density and is co-founder of the website DenseBreast-info.org, which provides information on breast density.

“I feel like I was denied the opportunity for an early diagnosis because I wasn’t told that I have dense breasts.”

Standard for all people who have a mammogram

According to a tracker on the website DenseBreast-info, an estimated 39 states and the District of Columbia already require that certain breast density information be included in the letters sent to patients. But wording in each state can vary and does not always require providers to inform patients of their risk, which is why advocates are pushing for a national requirement.

With the new FDA rule in place, informing patients about their breast density will become a nationwide requirement.

“This will now create a uniform national standard so that all women in all states will be told whether or not their breasts are dense when they have a mammogram,” said Dr. Wendie Berg, professor of radiology at the University of Pittsburgh School of Medicine and Magee-Womens Hospital of UPMC, co-founder and chief scientific advisor of DenseBreast-info.org.

The FDA’s new changes require facilities to provide patients with information about their breast density and to explicitly explain in the mammogram results letter how breast density may affect the accuracy of a mammogram.

An example of a notification might be: “Breast tissue may or may not be dense. Dense tissue makes it harder to detect breast cancer on a mammogram and also increases your risk of developing breast cancer. Your breast tissue is dense. For some people with dense tissue, imaging tests other than a mammogram may help detect cancer. Talk to your doctor about breast density, breast cancer risks, and your individual situation.”

Or a statement might be: “Breast tissue can be dense or non-dense. Dense tissue makes breast cancer harder to detect on a mammogram and also increases your risk of developing breast cancer. Your breast tissue is not dense. Talk to your doctor about breast density, breast cancer risks, and your individual situation.”

Understanding Breast Density

A mammogram report lists four categories of breast density, ranging from predominantly fatty to extremely dense, Berg said.

In predominantly fatty breasts, “cancer is very easy to detect, and these women have a much lower risk of developing breast cancer. The next category would be scattered fibroglandular density, which is actually the most common,” Berg said.

“And then heterogeneously dense, which can obscure masses — that category misses at least 25% of cancers,” she said. “And then extremely dense would be the last category, where at least 40% of cancers are missed. And if you compare a woman with extremely dense breast tissue to a woman with fat breasts, the risk of developing breast cancer is actually up to four times higher.”

Based on her own family history of breast cancer and her breast density, she determined ten years ago that her lifetime risk of developing the disease was 19.7%. For this reason, she insisted that her doctor should have an MRI of her breasts for cancer screening rather than just a 3D mammogram.

“The MRI showed a small invasive cancer that cannot be seen on my own mammogram,” said Berg, who has been treated for the disease ever since.

“After that experience, I said if we tell women they have dense breasts, there needs to be a place where women can find out if they meet the criteria for an MRI or if they want to have an ultrasound and what they can expect from those tests,” Berg said.

The FDA notes that for some people with dense breast tissue, imaging tests other than mammography may be helpful in detecting cancer.

“But that’s all it says. And then it ends with ‘Talk to your doctor,'” Berg said. “The guidelines are not as clear as they could be.”

Many women may not know whether to request additional imaging tests, such as an MRI, or in some cases their doctor may not think they need these procedures. In some cases, these options are also not covered by insurance.

“Knowledge is power, and all women can now have informed conversations with their doctors about the screening plan that is right for them, based on the factors that affect their personal risk of breast cancer, including breast density,” Molly Guthrie, vice president of policy and advocacy at Susan G. Komen, said in a statement.

“We want everyone to know that dense breast tissue alone does not require additional imaging – it is just one factor in breast cancer risk,” Guthrie added. “For those who need imaging beyond a mammogram, out-of-pocket costs are often a barrier. That’s why we have advocated for state and federal legislation to eliminate these costs. We have the technology to detect breast cancer earlier and save lives. Financial barriers should not stand in the way of that. It is critical that people understand and have affordable access to the breast imaging they need based on their individual risk.”

Access to high-quality mammograms

The American Cancer Society has welcomed the FDA’s new rule, saying it will reduce delays in diagnosis. It is estimated that about one in eight women will develop breast cancer in their lifetime.

“The final rule will improve screening by incorporating newer technologies, better enforcing facility accreditation and quality standards, and improving the reports provided to women and their physicians,” the ACS said in a statement last year.

The ACS said at the time that while the new changes could help reduce breast cancer death rates, more needed to be done to ensure that all women had access to high-quality mammograms.

According to the organization, “Black women are more likely to receive lower quality screening tests, contributing to the persistent disparity” in breast cancer mortality between black and white women.

A study published in 2022 found that the death rate from breast cancer fell by 43% over three decades, from 1989 to 2020, meaning 460,000 fewer breast cancer deaths during that period. When the data was analyzed by race, it was found that black women have a lower incidence of breast cancer than white women, but the death rate among black women overall was 40% higher.

“Either screening is important or it isn’t. And if it is important, it is certainly more important for women who we know are at increased risk and for whom mammography is a compromised tool,” Pushkin said. “When you inform a woman about her Beast density, you give her the opportunity to advocate for herself. How can you advocate for yourself if you don’t have enough information to know that you need to do that?”

CNN’s Janelle Chavez contributed to this report.

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