Breast density is an important indicator of breast cancer risk

Many of us know that some genetic factors can predict the risk of developing breast cancer. BRCA1 and BRCA2 mutations are the most common genetic causes of the disease. But new research suggests that breast density is an increasingly important predictor of a woman’s risk of developing breast cancer.

Breast density compares the amount of fat to the amount of tissue on the mammogram. Dense breasts contain more fibrous tissue and glands than fatty tissue. In general, younger women tend to have denser breasts, and breast density generally decreases with age.

Women with dense breasts are four to five times more likely to develop breast cancer than women with low breast density. Researchers are still trying to figure out why. We know that breast density can make it difficult to detect breast cancer on a mammogram. Because both cancer and dense breast tissue appear white or light gray on a mammogram, the dense tissue can hide a tumor from view.

Digital mammography has been found to be more accurate than mammography for women with denser breasts. In addition, mammography, ultrasound, and MRI are being studied to determine whether combining these tests will improve breast cancer detection in women with dense breasts.

While higher breast density increases the risk of breast cancer, it is not clear whether lower breast density will reduce the risk of breast cancer. For example, getting older and gaining weight after menopause are associated with decreased breast density, but they are also associated with an increased risk of breast cancer.

At this time, there are no specific screening guidelines for women with dense breasts. ^{The American College of Radiology Mammography Data and Reporting System ( BI} -RADS® ) measures breast density, but is not routinely reported or used to assess breast cancer risk.

With more research, individual breast cancer screening recommendations could replace current recommendations, and doctors could start using breast density to assess cancer risk. In the meantime, you can take charge of your health by asking questions and determining what works best for you. Susan G. Komen ^® offers some questions to ask your doctor:

• Are my breasts thick? If so, how do you know?
• What other things can affect the density of my breasts?
• What screening tests should I take and how often should I get them?
• If members of my family have dense breasts, do I also have thick breasts?
• What can I do to reduce my risk of breast cancer?

Learn more about risk factors for breast cancer.