Breast Density: What You Need to Know
Breast density refers to the relative amount of glandular and fibrous tissue that each woman has in her breasts compared with the amount of fatty tissue present. Each woman has a different breast density. You cannot know your breast density by a physical exam, it is only determined on a mammogram. Women with mostly fatty tissue do not have dense breasts and women with more fibrous or glandular tissue have dense breasts. Dense breasts are normal (not a disease) and are found in 40-50% of women.
Dense breasts appear more white on mammography. Because cancers usually appear white on mammograms, they are more difficult to detect the more white the mammogram appears.
Breast density is the most common reason for missing a cancer on a mammogram and women with dense breast tissue are also at slightly increased risk for breast cancer. Mammograms are still good at detecting breast cancer but the denser your breasts are, the less accurate they will be at detecting breast cancer.
How Does Breast Density Affect Your Health?
All women should have a discussion with their health care provider about their lifetime risk for breast cancer. If your lifetime risk for breast cancer is over 20%, you should have an MRI to supplement your annual mammogram, even if your breasts are not dense.
If your lifetime risk of breast cancer is less than 20%, you should know that 3D mammography improves cancer detection in all breast densities but especially for women with heterogeneously dense breasts. We recommend that all women consider having 3D mammography.
1 in 8 women will develop breast cancer over the course of their lifetime so the average women's lifetime risk of breast cancer is 12-13%.
If you have dense breasts and other risk factors for breast cancer, discuss your risk and density with your doctor. This will help guide discussions about screening and which tests might be right for you. Screening decisions should take into account your values and philosophy.
There are no medical guidelines for additional screening for women with dense breasts but some women may prefer to add additional testing to help detect breast cancer. Each additional test may add additional cost, anxiety and chances to detect abnormalities that are not cancer (false positives). It is therefore a personal decision about how much you are willing to do for the chance that should you be diagnosed with breast cancer, that it will be detected as early as possible.
Please be aware that some supplementary screenings may not be covered by insurance. So talk with your doctor and check with your insurance company to help you make your decisions on screening. There are no straightforward answers for women with dense breasts.
Screenings could include:
- Mammogram – A mammogram uses low-level X-ray to detect changes in breast tissue. If you are a woman age 40 or older and in good health, the radiologists who are experts in interpreting breast imaging recommend you have a mammogram every year, as this regimen is proven to detect the most cancers at the earliest stage. Other physicians may recommend different screening regimens, based on a different value placed on the harms of false positives and additional testing. It is a personal decision, that only each women can answer.
- 3D Mammography (Tomosynthesis) – A 3D Mammogram improves detection further – and has the added advantages of reducing false positive results. It is a good way to improve cancer detection whether or not your breasts are dense. There is no significant additional radiation, there are fewer false positives and most insurance now covers it.
- Breast Ultrasound – Whole breast ultrasound can be used to supplement mammography screening if you wish to pursue additional testing. Ultrasound detects more small invasive cancers than mammography, but it has a higher false positive rate. Additional cancers may be detected but at a cost of additional follow up testing and biopsies. The risk of having to undergo additional testing does go down after a few years of screening.
- Breast MRI – Breast MRI is usually recommended for women at elevated risk for breast cancer regardless of their breast density (as a supplement to mammography). It is the best test we have to detect cancer in women at high risk.
Helpful Resources and Websites
There are many helpful resources and websites if you would like to learn more information about breast density. We recommend the following:
Why Choose Us
Named a Breast Imaging Center of Excellence by the American College of Radiology, the UVM Medical Center offers specialized expertise and exceeds rigorous standards for breast imaging care. Mammograms are interepreted with a high level of expertise by experienced radiologists who specialize in breast imaging. We have the highest volume of studies in the state and research has documented that quality improves with numbers of studies interpreted.
We can provide for all of your breast imaging needs, including needle biopsies for diagnosis in a patient centered environment where a friend or family member can be present if you wish. We are staffed by a talented and dedicated group of knowledgeable and caring breast imaging radiologists, technologists and sonographers. We definitely try to put the patient first.
For more information call 802-847-2446 or email us with questions at firstname.lastname@example.org