Women with dense breasts

Did you receive a letter after your recent mammogram telling you that you have dense breast tissue? If so, don’t panic. Dense breast tissue is normal and seen in 40 to 50% of women. Breast density is not something that can be seen by your doctor, it needs to be detected in a mammogram. In Massachusetts, mammogram screening clinics are required to send any patient whose recent mammogram shows dense breast tissue a letter with information about what this means and where they may find answers to additional questions.

It’s important that women who have dense breasts are aware of it because they may make detection of breast cancer more difficult on a mammogram and may require additional screening at some point in their lives.

What is “dense” breast tissue?

On a mammogram, the appearance of breast tissue ranges from fatty to dense. If a mammogram report describes a patient’s breast as being “dense,” it means there is more fibrous tissue (tissue that gives breasts size and shape) and glandular tissue (produces milk), than there is fat.

Dense breast tissue, benign breast cysts and solid masses, and/or breast cancers all look white on a mammogram. Fatty tissue looks black. On a black background, it’s easier to see a tumor that looks white. Because of the whiteness, dense breast tissue can make it more difficult for radiologists to see breast masses and tumors.

Why do some women have dense breast tissue?

Many women start out with dense breast tissue that becomes fatty over time. However, some women’s breasts remain dense as they age. Researchers have not been able to specifically determine why some women have denser breast tissue than others, but there are some theories that are thought to increase your likelihood of having them.

You may be more likely to have dense breast tissue if you are between the ages of 40 and 50. You may have dense breast tissue at any age, but they normally becomes less dense as you get older. Estrogen levels are also thought to have an impact on breast density, because of this premenopausal women are more likely to have dense breasts than postmenopausal women. Women who take hormone medication to relieve menopause symptoms are also more likely to have dense breasts.

My mammogram report revealed that I have dense breast tissue, now what?

While dense breast tissue is normal, women with it do have a slightly higher risk of breast cancer compared to women with fattier breast tissue, which is why it’s listed as a risk factor for breast cancer. It’s unclear at this time why women with dense breasts are at higher risk of developing breast cancer.

If you have dense breasts, your provider may suggest additional screening; this is possible and common in all women, not just those who have dense breasts. Your provider considers several risk factors such as family history and prior breast screening results before determining if you need additional screening.

Additional screening may include use of 3D mammography (tomosynthesis) or a screening MRI of the breasts, a test that is exquisitely sensitive for detection of breast cancer, even in women with dense breasts. Both tests are available and in use at Boston Medical Center.

Talk to your provider

A copy of your mammogram report will always be sent to your primary care provider to be included in your medical record. Included in your report is a description of the density of your breast tissue. Make an appointment with your provider to discuss your mammogram report so you can know if you need additional screening. Talk to your provider about family history or other risk factors and ask if you may need additional screening, including breast MRI.

Book your yearly mammogram

Regardless of breast density, a mammogram remains the most important examination to screen for breast cancer in women over 40. Mammograms can help save lives so be sure to continue scheduling yours every year regardless of breast density. In addition to age, other risk factors include:

• Your family’s breast cancer history or an inherited mutated BRCA gene
• Sedentary lifestyle
• Being overweight
• Certain hormone replacement therapies
• If you’ve had breast cancer before
• Prior treatment with radiation therapy
• Having dense breasts

Book your yearly mammogram at BMC
617.414.8282
BMC.org/BookaMammo