Breasts are made up of a mixture of fibrous and glandular tissue and fatty
tissue. Your breasts are considered dense if you have a lot of fibrous
or glandular tissue but not much fat. Density usually decreases with age.
Breast density is determined by the radiologist who reads your mammogram
and will be included in your imaging report. In fact, under the NJ Breast
Density Law, reports must include information about breast density. The
legislation also requires insurers to cover follow-up evaluations, such
as ultrasound or MRI, in women with dense breast tissue.
Why is breast density Important?
Dense breasts do make it more difficult for doctors to spot cancer on mammograms.
Having dense breast tissue may increase your risk of getting breast cancer
If I have dense breasts, do I still need a mammogram?
Yes, a mammogram is the only medical imaging screening test proven to reduce
breast cancer deaths. Many cancers are seen on mammograms even if you
have dense breast tissue.
What should I do if I have dense breasts?
If you have dense breasts, talk to your doctor. Together, you can decide
which, if any, additional screening exams are right for you.
For a referral to a RWJBarnabas Health primary care physician or breast
specialist, call 888-724-7123.
What New Jersey Law Regarding Breast Density Means for Patients and Physicians
As of May 1, a new law went into effect for the State of New Jersey regarding
breast density, providing for additional screening coverage for women
with extremely dense breasts.
Breast density on mammography refers to the relative density of fibroglandular
tissue vs. fat. The greater the amount of fibroglandular tissue (seen
as white on mammograms) vs. fat (seen as gray), the greater the chance
of a breast cancer hiding from sight. Also, since breast cancer develops
primarily from glandular tissue and ducts, the greater the amount of fibroglandular
tissue, the greater the substrate for developing cancer.
The American College of Radiology defines breast density on mammograms
in four categories:
-Almost entirely fatty: 10 percent of women
-Scattered areas of fibroglandular tissue: 40 percent of women
-Heterogeneously dense tissue: 40 percent of women
-Extremely dense tissue: 10 percent of women
Those women with "extremely dense" breasts have two times the
risk of developing breast cancer than the average female population. As
per the new law, those women with this category of density are eligible
for additional methods of screening for breast cancer, covered by insurance.
The additional methods can help to detect cancer that may not be seen on
mammograms. The main two supplementary methods are whole-breast ultrasound
and breast MRI. Ultrasound is preferable for women with an average risk
for developing breast cancer, while for women at high risk, such as women
with a family history of breast cancer, MRI is a better choice.
Please note that these supplementary tests are in conjunction with and
don't replace mammography, which remains the main screening tool.
For more information, visit the breast center website at
Monmouth Medical Center's Jacqueline M. Wilentz Breast Center. Additional online resources include:
-American College of Radiology at
-American Cancer Society at
-Are You Dense Advocacy at