Health care providers that offer mammograms officially have a new standard to follow.

On September 10, a final FDA rule amending the Mammography Quality Standards Act went into effect. It mandates that women who have undergone mammograms receive information on breast density. In particular, they must be informed that it raises the risk of developing breast cancer and can make mammograms harder to read. The goal is to ensure more women are aware of these issues so that more cancers can be caught early.

The FDA had initially issued this final rule in March 2023. It also requires patient reports to classify breasts into one of four categories: almost entirely fatty, scattered areas of density, heterogeneously dense, or extremely dense. The latter two are considered to be dense breasts, and about 50% of women of mammography age have them.

You may be able to see this report on your patient portal, but if not, providers also have a new requirement for what they need to tell their patients after the fact. Each patient must be informed about the risks associated with dense breasts and their mammography difficulties, and then they should be told which type of breasts they have. For those on the denser side, providers should share that additional imaging may be helpful. Current options for additional imaging may include 3D mammography, ultrasound, or MRI. Each patient, however, should be encouraged to talk to their doctors about breast density, risks, and their own personal situations.

Breast density reflects how much fibrous and glandular tissue, or fibroglandular tissue, is in the breast. These tissues are harder to see through on a mammogram. Some women may lose density as they age, but many do not.

The American Cancer Society says while it is known that dense breasts increase the risk of breast cancer, the cause is not currently known. One theory is that dense tissue has more cells that can then become abnormal.

Despite the fact that these tissues may not be entirely compatible with a mammogram, the ACS reminds women that most breast cancers are still caught by mammograms, even in those with dense breasts, so you should continue to get those screenings. It is, however, important to talk with your doctor about any supplemental screening that may be helpful.