5 Things to Know About Breast Density

Chances are, if you’ve scrolled through social media recently, you’ve noticed a sharp uptick in mentions of “dense breasts.” 

In March, the U.S. Food and Drug Administration (FDA) announced that mammography facilities must begin notifying patients about their breast density by September 2024. Under the updated regulations, women’s mammogram results will soon include standardized language indicating whether their breast tissue is “dense” or “not dense.” 

Before the new rules take effect, here are five things women need to know about breast density:

1. Dense breasts are common. The National Institutes of Health reports that nearly half of women over 40 years old — the recommended age to start getting mammograms — have dense breast tissue.

2. Breast density cannot be determined by feel. Breast density is determined by a radiologist’s assessment of a woman’s percentage of dense, glandular tissue and not dense, fatty tissue. When a woman has more glands and fibrous tissues, the denser her breast tissue will appear on a mammogram.

3. Having dense breasts can make it harder to detect cancer. Dense tissue and breast cancer both appear white on mammograms. This masking effect can often result in cancer being found when larger or at more advanced stages.

4. Breast density is an independent risk factor for breast cancer. Studies show that women with the highest breast density are four to six times more likely to get breast cancer than individuals with the least dense breasts.

5. Having dense breasts does not mean a woman will get breast cancer. If a woman is aware she has dense breasts, she should talk to her health care provider about her risk and what supplemental imaging, if any, is needed.

When it comes to protecting women’s breast health, education and empowerment are key. The FDA’s expanded mammography regulations are a welcome step in the continued fight to prevent, treat and detect breast cancer.


Stacy Smith-Foley, M.D., is a board-certified breast imaging specialist at The Breast Center at CARTI who is passionate about promoting breast cancer awareness and educating women about their risks. 


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