Dense breasts on your mammogram report
Since September 10, 2024, every US mammogram report has to say whether your breast tissue is dense. Here is what the notice means, what the main guidelines say about extra imaging, and what to ask your doctor. (FDA, 2024)
What the notice says
The FDA rule requires the report to place your breasts in one of four density categories, and your letter to include one of two standard statements. (FDA, 2024)
- Not dense: "The breasts are almost entirely fatty" or "There are scattered areas of fibroglandular density."
- Dense: "The breasts are heterogeneously dense, which may obscure small masses" or "The breasts are extremely dense, which lowers the sensitivity of mammography."
If your tissue is dense, the letter says that dense tissue makes cancer harder to find on a mammogram and raises the risk of breast cancer, that in some people other imaging tests may help find cancers, and that you should talk to your healthcare provider about breast density, risk and your situation. (FDA, 2024)
About half of US women who have mammograms have dense breasts. (ACS, 2024)
What the guidelines say about extra imaging
| Group | Mammograms | Extra ultrasound or MRI |
|---|---|---|
| USPSTF | Every 2 years, 40 to 74, also with dense breasts | Evidence insufficient to recommend for or against after a normal mammogram (grade I) (USPSTF, 2024) |
| American Cancer Society | Same as its general advice; this page does not change the schedule | Ultrasound and possibly MRI can find some cancers a mammogram misses, but also more findings that are not cancer, leading to more tests; cost may not be covered. Women already at high risk should have an MRI with their yearly mammogram (ACS, 2024) |
| American College of Radiology | Yearly from 40 at average risk | For women with dense breasts who want extra screening, MRI is recommended; contrast-enhanced mammography or ultrasound if MRI is not possible (ACR, 2023) |
Questions to ask your doctor
- Which density category is on my report?
- Given my family history and other risk factors, is my overall breast cancer risk average or higher? (See family history and screening.)
- Would an ultrasound or MRI add anything for me, and what are the chances of a false alarm?
- Would my insurance cover it?
The ACS advises making sure your doctor knows anything in your medical history that raises your breast cancer risk. (ACS, 2024)
Questions people ask
My report says I have dense breasts. Is something wrong?
No. Dense breasts are common: the American Cancer Society says about half of US women who have mammograms have them. Dense tissue makes cancer harder to see on a mammogram and is linked to a higher risk of breast cancer, which is why the report now tells you. (ACS, 2024)
Do I need an ultrasound or MRI if my breasts are dense?
Guidelines differ. The USPSTF found the evidence insufficient to recommend for or against extra ultrasound or MRI after a normal mammogram. The ACR recommends MRI for women with dense breasts who want extra screening. Decide with your doctor, based on your overall risk. (USPSTF, 2024) (ACR, 2023)
Should I still have mammograms?
Yes. The USPSTF advice of a mammogram every 2 years from 40 to 74 also applies to women with dense breasts. (USPSTF, 2024)
Since when do reports mention breast density?
Under an FDA rule issued March 10, 2023, every facility covered by the Mammography Quality Standards Act has had to include a breast density notice since September 10, 2024. (FDA, 2024)