Breast Tissue Density Awareness

For immediate release: October 01, 2013

New Maryland Legislation Effective October 1, 2013

As of October 1, 2013, Maryland law requires that mammography providers include information about breast tissue density in letters notifying women of the results of their screening mammogram. The notification recommends that women discuss the information with their health care provider.

Women undergoing screening mammogram will continue to receive a letter with their mammogram results within 30 days of the date of the exam, as mandated by the federal Mammography Quality Standard Act. Additionally, according to the new Maryland law, the result letter sent to women will now include a notice about breast tissue density at mammography.

The Maryland Radiological Society, a Chapter of the American College of Radiology, appointed a Task Force on Breast Density led by a breast imaging expert at the University of Maryland Greenebaum Cancer Center, Judy Grant, M.D. The Task Force recommendations include guidelines for mammography providers, referring health care providers and the general public.

Guidelines for Mammography Providers

  • Guidelines for Mammography providers. As of October 1, 2013, screening result letters need to include the notice stated in Chapter 457 and reported below. The screening result letter does not need to specify the patient's own breast density and may contain additional informative material or statements.

  • The law requires that screening result letters sent to women must include the following notice verbatim:

    • "This notice contains the results of your recent mammogram, including information about breast density. If your mammogram shows that your breast tissue is dense, you should know that dense breast tissue is a common finding and is not abnormal, with about half of women having dense or highly dense breasts. However, dense breast tissue can make it harder to find cancer on a mammogram and may also be associated with an increased risk of cancer. This information about the result of your mammogram is given to you to raise your awareness and to inform your conversations with your physician. Together, you can decide which screening options are right for you based on your mammogram results, individual risk factors, or physical examination. A report of your results was sent to your physician."

Guidelines for Referring Health Care Providers

  • Guidelines for Referring Health Care Providers: The American College of Radiology encourages and instructs mammography providers to include information regarding breast density in every mammogram report released to the referring health care provider. Breast density varies depending on the composition of the breast and the proportion of fibroglandular tissue relative to fat. Breast composition is arbitrarily classified and subjectively assessed visually into four types according to the Breast Imaging-Reporting And Data System (BI-RADS): 1) almost entirely fat, 2) scattered fibroglandular densities, 3) heterogeneously, and 4) extremely dense breast tissue. The visual assessment is not reliably reproducible. Dense breast tissue may obscure an underlying breast cancer and may also represent a risk factor for breast cancer. However, as stated above, high mammographic breast density has not been shown to be associated with risk of death in patients with breast cancer in a large prospective study. Currently, there are no randomized trials data demonstrating that adding either MRI or ultrasound to mammography saves lives. Therefore, the decision to pursue additional screening should not be based on breast density alone but on the overall risk profile. The patient should be counseled regarding the potential for false positive findings and the need for additional interventional procedures. There should always be a conversation between the patient and her health care provider before ordering supplemental tests.

Informative material with answers to frequently asked questions about breast density and breast cancer risk is available online at the website The information in this website is based on current scientific knowledge and is provided by expert radiologists of the California Breast Density Information Group. This website can be utilized as a source of medical information but not as a reference for the law as California, as opposed to Maryland, has a notification provision which requires women's notification of their own breast density.

Guidelines for Women

Guidelines for the general public:

  • Women receiving the notice in the result letter should consider the following important information:

  • What is breast density.

  • What are the implications of breast density in terms of the ability to detect breast cancer on a mammogram, the risk of breast cancer, and the risk of death from breast cancer.

The recommendations for breast cancer screening in women with dense breasts.
In general, breast density refers to the appearance of the breast tissue on mammography. A breast is composed of fat, glandular and connective tissue. A dense breast on mammography has less fat than glandular and connective tissue. The breast composition varies among individuals: it may be mostly fatty or very dense or contain a mixed amount of fat and glandular tissue. The vast majority of women have mixed breast composition, 10% of women have fatty breasts and 10% extremely dense breasts. Breast composition and breast tissue density may also vary with age and menstrual cycle.

A dense breast and breast cancer are both white on mammography. So, it may be more difficult to detect breast cancer in a dense breast. Additionally, some studies have shown that dense breast tissue increases risk for breast cancer. The good news is that women with dense breasts are not at increased risk of dying from breast cancer when compared to women with mostly fatty breasts.

Women with dense breasts should continue annual mammographic screening. Screening mammography is the only test that has been proven to decrease breast cancer mortality. Supplemental screening after mammography with breast MRI or ultrasound in women with dense breasts is not standard of care or supported by scientific evidence. A risk-based approach is advised. A woman should discuss the results of her mammogram with her health care provider and understand her risk of having breast cancer. If needed, a genetic counselor may be consulted. If a woman is at high risk for breast cancer, supplemental testing may be beneficial, in particular with breast MRI. It should be kept in mind that supplemental screening tests may generate unnecessary follow-up or biopsies and more "false alarms" compared to mammography.

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