June 11, 2025 — Have you checked your annual mammogram off your health to-do list? That’s a relief, for sure — but there’s one more critical step to take after you get your results.
Go over your report to see if you have dense breast tissue.
For more than 40% of women, the answer is yes. And that means you may want to consider supplemental testing.
The next step isn’t always clear. But two new studies compared your options. Here’s what to know.
1. Having dense breasts increases your risk of breast cancer.
Why it matters: Not only is the risk higher, but it’s also harder to detect cancer in dense breasts.
What to know: Dense breasts have more fibrous tissue and milk glands than fat tissue. On a mammogram, the dense areas show up as white — the same color as cancer. That can make cancer harder to see, particularly when it’s small.
Federal law (since last fall) requires that you be notified whether your mammogram shows you have dense breasts. To be certain, check your patient portal report or call your doctor’s office.
You’ll also want to find out if you have “heterogeneously dense” or “extremely dense” breasts. What’s the difference? "Heterogeneously dense" means most of the breast is dense with some areas of fat, and "extremely dense" means the breast has almost no fatty tissue. Breasts can become less dense over time, especially around menopause, so you need to recheck your report every year. Dense breasts can only be diagnosed with imaging — a physical exam can’t tell.
Bottom line: “Women should know that if they have dense breasts, the mammogram might not see their cancer,” said Ruth Etzioni, PhD, a biostatistician at Fred Hutchinson Cancer Center in Seattle who specializes in analyzing benefit-harm tradeoffs in cancer screening tests.
2. If you have dense breasts, consider supplemental screening.
Why it matters: Between 25% and 30% of cancers in heterogeneously dense breasts are missed on a standard mammogram. That number for extremely dense breasts is even higher, potentially topping 40%.
What to know: Knowing your breast density type can help you understand how likely a mammogram would be to miss cancer in your breast. But that’s only one part of the decision-making equation. For those with heterogeneously dense breasts, “we typically will consider other risk factors in addition to breast density in order to decide whether to recommend supplemental screening,” said dense-breast expert Wendie A. Berg, MD, PhD, a radiologist at the University of Pittsburgh School of Medicine. A list of risk factors, including family history and high BMI after menopause, is available at DenseBreast-info.org.
Bottom line: If you have extremely dense breasts, you should get supplemental screening, Berg said. If you have heterogeneously dense breasts, you should know your risk factors and talk to your doctor about what makes sense for you.
3. There are three types of supplemental screenings.
Why it matters: Researchers compared these techniques — ultrasound, MRI, and contrast-enhanced mammogram — by randomly assigning them to women ages 50 to 70 with dense breasts whose mammograms didn’t detect cancer. Results showed that MRI and the contrast-enhanced mammogram (using an iodine-based dye that helps reveal cancers) each found nearly five times as many cancers as ultrasound.
What to know: Contrast-enhanced mammogram detected 19.2 cancers per 1,000 people scanned; MRI detected 17.4 per 1,000 scans; ultrasound detected 4.2 per 1,000. These detection rates were somewhat higher than in past studies, Berg and Etzioni said. They noted that women who get the scans repeated annually often see those detection rates drop over time. (That’s because you’re more likely to have an undetected past cancer than to develop a new one in the next year.)
A separate study in JAMA Oncology recently showed that among women with a family history of breast cancer, just getting a slightly better scan than a standard mammogram — called a 3D mammogram — offered improved detection of advanced cancer in women with extremely dense breasts. “That was compelling that we should really be doing [3D mammogram] as the routine screening, at least for the basic screening,” Berg said.
Bottom line: If you have a family history of breast cancer, request a 3D mammogram for your initial annual screen, and when considering supplemental scans, know that some are better than others.
4. Your doctor may not automatically suggest supplemental screening.
Why it matters: Berg’s own doctor questioned her request to get an MRI after Berg learned that she has dense breasts. Ultimately, she got the MRI, which showed a small cancer that she said was easily treated and she has recovered.
What to know: An advisory group called the U.S. Preventative Services Task Force that typically influences what insurance will cover doesn’t recommend supplemental screening for people with dense breasts. Their reason: There is no multi-year clinical trial data examining whether extra screenings have drawbacks.
Bottom line: It’s OK to request supplemental screening, and knowing your risk factors will help during that conversation with your doctor. “You still can’t count on your doctor to provide all the information that you might need to make a decision for yourself about supplemental screening,” Berg said.
5. Not all supplemental screenings are covered by insurance.
Why it matters: Not every state requires insurance to cover supplemental screenings — and in those that do, the law may not apply to every type of insurance. DenseBreast-info.org maintains a list of which states and plan types are required to cover it.
What to know: Without coverage, out-of-pocket costs for an MRI can reach thousands of dollars, but a type called “abbreviated” or “quick” MRI can be lower — between $300 and $600 total. Contrast mammography and ultrasound are usually even less, and a 3D mammogram can sometimes cost an extra $40 or $50.
MRIs where Berg works in Pittsburgh are booking six months out. Contrast-enhanced mammograms are not FDA approved for screening, but Berg said some centers are starting to offer them as a diagnostic option, monitored by a radiologist. The procedure takes about 15 minutes, including the contrast dye injection, and uses a modified mammogram machine.
Bottom line: “If you have heterogeneously dense breasts, I think it really does come down to your own tolerance of other risk factors and whether your insurance will cover it, so it is more of a personal choice,” Berg said.
6. Think through your benefit/harm tradeoffs.
Why it matters: Getting extra scans can be stressful, potentially expensive, and require a lot of time researching and communicating with your provider — not to mention taking time off work for appointments.
What to know: Your risk calculation is complex, including the risk of missing a cancer detection. For example, ultrasound does have advantages (it’s noninvasive, inexpensive, and does not use ionizing radiation) but tends not to spot cancer until the tumor is larger. There’s also about a 10% risk of a false positive with most screening types.
“You have to poke a lot of people to find the people that you can help,” said Etzioni, who is an expert in data-driven medical decision-making, particularly when it comes to diagnostic testing and early cancer diagnosis.
Bottom line: Deciding whether to get additional screening is personal and involves weighing your comfort with risk and the potential stress and cost of a false positive, Berg said. “I think it’s hard — you don’t want to have any regrets either way. I don’t know anybody who has regrets that their cancer was found too small. It’s always better — if it’s going to be there — to find it as early as possible.”
