How Breast Density Affects Mammogram Results

According to the American Cancer Society, breast tissue is considered dense if the breast contains a lot of fibrous or glandular breast tissue and not much fat. Many women have dense breasts, but most women’s breasts lose density with age. For some women, though, breast density stays the same even as time passes.

Doctors are unsure why women with dense breasts are more at risk for breast cancer. However, the reason dense breasts make it more difficult for a mammogram to detect breast cancer is fairly straightforward: Dense breast tissue can mask signs of cancer and make it more difficult to see in an X-ray.

Many women have dense breasts, but most women’s breasts lose density with age.

Fibrous and glandular tissue appear white in a mammogram, as do masses and tumors, while fatty tissue appears almost black, according to the Mayo Clinic. For this reason, mammograms tend to be less accurate for women with dense breasts.

It’s also important to note that breast density doesn’t affect the way they feel, and there’s no way to see density with the naked eye. Whether you have dense breasts can only be determined with a mammogram.

Density & mammograms

Should you still get a mammogram if you have dense breasts?

The simple answer is yes.

While dense breasts do make interpreting mammograms a bit more difficult, a mammogram is still an effective and necessary screening tool, according to medical experts. A digital mammogram is the most common type. Saving your mammogram as a digital file rather than on film allows doctors to perform a more detailed analysis of the results, according to the Mayo Clinic.

Dense breast tissue can mask signs of cancer and make it more difficult to see in an X-ray.

Medical organizations recommend that women with an average risk of breast cancer start getting regular, annual mammograms beginning at age 40. Women with dense breasts and no other risk factors for breast cancer may benefit from getting annual exams at an earlier age.

More screening tools for dense breasts

Other tests may be more effective at detecting cancer in dense breasts, but they carry additional risks. Some more common supplemental breast cancer screening tests include a 3-D mammogram, a breast MRI, a breast ultrasound and molecular breast imaging. Keep in mind that these additional tests have not been proved to reduce the risk of dying from breast cancer, according to the Mayo Clinic.

Also known as breast tomosynthesis, a 3-D mammogram uses X-rays to collect images of the breast from multiple angles. The images are then synthesized and turned into a three-dimensional image.

A breast MRI (magnetic resonance imaging) uses magnets, not radiation, to create images of the breast and is typically recommended for women who are at a very high risk of developing breast cancer.

An ultrasound of the breast uses soundwaves to analyze breast tissue. It is often used to further examine areas of the breast that caused concern in a mammogram.

Other tests may be more effective at detecting cancer in dense breasts, but they carry additional risks.

In molecular breast imaging, a special camera is used to record the activity of a radioactive tracer that is injected into a vein in the patient’s arm ahead of the procedure. The tracer reacts differently when it comes into contact with cancerous tissue; the camera can record these reactions, or the lack of them. This test is usually conducted every other year in conjunction with an annual mammogram.

Despite the challenges that dense breasts present, doctors still believe mammograms to be an effective screening tool. However, if you are interested in additional testing, be sure to first discuss with your doctor the pros and cons associated with each test, and remember that none of them has been proved to reduce the risk of dying from breast cancer.