In an update to the Food and Drug Administration’s mammography regulations, released in March, mammography facilities across the country must notify women about the density of their breasts. Such facilities include hospitals, outpatient departments, clinics, radiology practices, doctors’ offices, and mobile units that conduct breast cancer screenings—though they have until September 2024 to fully comply.
Thirty-eight states, including California, Connecticut, Illinois, New York, Texas, and Virginia, already mandate that facilities inform women about their breast density, but the specifics vary from state to state. This federal regulation, which had been in the works for over a decade, will provide a national standard for notification.
Why does density matter? According to the FDA, about half of all women in the U.S. over age 40 have dense breasts, which is an independent risk factor for breast cancer (the greater the density, the greater the risk). By various estimates, having extremely dense breasts raises the risk of breast cancer at least twofold, compared to women with non-dense breasts. Yet many women are unaware of their breast density. You can’t tell by the shape, size, or feel of a breast—only a mammogram can reveal dense breasts, and just how dense they are.
But herein lies the problem and thus the reason for the updated regulation: Dense breasts have more fibrous and glandular tissue and less fat, and this dense tissue appears as white spots on mammograms just like tumors do, which can make it difficult for radiologists to interpret the images. That is, the test can miss cancers in women with dense breasts. In contrast, non-dense breasts are mostly fat, which doesn’t obscure tumors on mammograms.
As per the new regulation, the mammogram report sent to the patient will say either, “Your breast tissue is not dense” or “Your breast tissue is dense.” The report must also state that having dense breasts can affect the results of the mammogram and that women should talk with their healthcare provider about breast density, breast cancer risk factors, and their individual situation; other imaging tests in addition to mammography may be indicated for some women with dense breasts.
The Mammography Quality Standards Act was enacted in 1992 to ensure that mammography providers deliver quality care; it gave the FDA the authority to oversee the accreditation, certification, and annual inspection of facilities. The update to it is intended to help women make better-informed decisions about their breast health and screening options in consultation with their healthcare provider.
Because the new regulation doesn’t go into full effect for quite some time, if you live in a state that doesn’t currently require notification, ask the radiologist or your physician the next time you have a mammogram. You’re more likely to have dense breasts if you are younger, have never been pregnant or had children at a later age, have been on hormone therapy, or have a family history of breast cancer. After menopause, breast density tends to decrease.