Dense breast tissue is a measure of how much breast tissue is on your mammogram versus fat. On a mammogram, fat is actually gray in color while tissue and cancer shows up as white.

“When you have more white, dense breast tissue on your mammogram, it becomes more difficult to find a white breast cancer hiding in your white breast tissue,” said Dr. Kristie Guite, a Marshfield Clinic Health System breast imaging radiologist.

A Wisconsin law requiring doctors to notify women they have dense breast tissue on their mammogram went into effect April 4, 2018. Doctors should send the notice to patients with their exam results via a letter sent in the mail.

Next steps for women with dense breast tissue

Dense breast tissue is found in more than 40 percent of women older than 40. Women with it also have an increased risk for developing breast cancer.

If a radiologist detects dense breast tissue on your mammogram, you should discuss this with your doctor. They help you determine whether you should undergo additional screening such as 3D mammography, molecular breast imaging or possibly an MRI.

For women, doctors recommend a yearly mammogram starting at age 40. Women in their 40s and 50s are also more likely to have dense breast tissue on a mammogram. This dense breast tissue can decrease with age.

Breast density is not determined by how the breast looks or feels and is only determined on a mammogram.

Watch this video for more information, or talk to your doctor.