As of January 1, 2014, the state of Illinois requires health facilities that provide mammograms to notify women if they have dense breasts in accordance with Senate Bill SB2314. Illinois is one of at least 28 states that either are working on legislation or have already passed it.
The surprisingly controversial law, having to do with a woman’s right to know if her mammogram result is unclear, acknowledges that dense breast tissue makes it harder to identify cancer on a mammogram.
Minor details of breast density legislation differ by state. For example, Illinois is one of the only three states that currently mandate insurance reimbursement for supplemental screening exams for women with dense breasts.
A problem in screening women with dense breasts for cancer is that fibrous and glandular tissue are (literally) dense, rendering cloudy-white, blobby images in mammograms. Normal fat, by contrast, tends to appear dark gray or black in the images. The benign fibroglandular material tends to mask cancer, so a radiologist is less likely to see it.
Upon knowing they have dense breasts, women might choose additional screening such as by breast thermography, ultrasound or MRI.