What Does it Mean to Have Dense Breasts?

Did your last mammogram report say you have dense breasts? It’s more common than you think. Almost half of all women who get mammograms are found to have dense breasts, and many don’t know what it means.

Understanding dense breast tissue

Breast density describes the different kinds of tissue that show on your mammogram. Your breasts are made of fat, connective tissue, and milk ducts and lobules that together are called glandular tissue. Dense breasts have higher amounts of glandular and connective tissue and lower amounts of fatty tissue. Breast density matters because women with dense breasts have a higher risk for breast cancer than women with fatty breasts.

The radiologist who reviews your mammogram classifies your breasts according to these 4 groups:

• Almost entirely fat (about 1 in 10 women)
• Some dense areas: scattered areas of dense glandular and connective tissue (about 2 in 5 women)
• Many dense areas: numerous areas of glandular and connective tissue (about 2 in 5 women)
• Extremely dense: almost all glandular and connective tissue and little fat (about 1 in 10 women)

Dense breasts fall into groups C and D. Dense areas look white in a mammogram, the same color as cancer, making it tricky for doctors to read the images and find breast cancer.

Factors affecting breast density

Experts aren’t sure why having dense breasts increases your risk for cancer. Typically, breast density is inherited, but other factors can influence it. You may have higher breast density if you’ve used postmenopausal hormone replacement therapy or are underweight for your height. You are more likely to have lower breast density as you age, if you have had children, or if you have taken a breast cancer prevention medicine called tamoxifen.

Should you have additional tests?

If you have dense breasts, speak with your doctor about your personal risk factors for breast cancer and whether you should have more screening tests, such as 3-D mammography, a breast ultrasound, or an MRI exam. No screening recommendations beyond mammography have been established for dense breasts, although research is underway. Some states require healthcare providers to notify you if your mammogram shows you have dense breasts. Many states also require insurance providers to cover additional imaging tests. Learn more about the legislation in your area.

Regular screening is key to catching breast cancer early. You can also reduce your cancer risk by maintaining a healthy body weight, getting enough exercise, and limiting alcoholic drinks.

Click here to learn more about the comprehensive imaging services offered at Touro’s Women’s Imaging Center.