May 2019

Illinois Public Act 100-0749 was signed into law in 2018 and requires health professionals to notify individuals via a summary of the mammography report if the mammogram indicates the individual has dense breast tissue. The law requires notification only, and does not establish any other obligations for a physician or the healthcare team.

What Are Dense Breasts and How Are They Identified?

Breasts are considered dense if there is a relatively high proportion of fibrous or glandular tissue to fat in the breast. Dense breasts can only be identified via mammography. Radiologists are trained to assess breast density along with identifying breast abnormalities, when they read a mammogram.

The Breast Imaging Reporting and Data System (BI-RADS) is used to classify breast density into four categories, ranging from very fatty tissue to very dense tissue. This information is often included as part of the standard mammography report, but its reporting has not been previously mandated in Illinois. According to the American College of Radiology, the assessment of breast density is subjective, and may vary based on the physician interpreting the mammogram.

The Link Between Dense Breasts and Cancer

There is some evidence that dense breast tissue in and of itself can lead to a higher risk of developing breast cancer. However, a potentially larger concern is that it may be more difficult to detect cancer via mammograms in women with dense breasts. Awareness of the relative density of a patient’s breast tissue can provide important information for a referring physician about how to advise a patient about mammogram results, breast health and the relative risks and benefits of supplemental screening.

Patient Notification and Education

Currently, 36 states require some form of reporting or notification about dense breasts, although the type and content of the notification varies.

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