Breast Density: What You Don't Know Could Affect Your Health

Breast density can affect mammogram results, but many women may not understand its implications for breast cancer

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) What you don’t know about your breast density may affect your decision-making when it comes to breast cancer screenings like mammograms.

A new study, led by Deborah J. Rhodes, MD, a consultant in preventive medicine at the Mayo Clinic, found that women often did not understand what breast density is or why it matters.

Dr. Rhodes and team called for continued and improved educational efforts.

"The results of our study support the need for continued efforts to improve awareness of breast density and its implications on screening among women who are eligible for screening mammograms," Dr. Rhodes said in a press release.

Adam M. Brufsky, MD, PhD, a specialist in cancer treatment at the University of Pittsburgh Medical Center and the co-director of the Comprehensive Breast Cancer Center, told dailyRx News that "Both the [primary care provider] and the radiologist should educate women about breast density, since both physicians are involved in ordering and acting on breast screening modalities."

He added that new technology may make this less of an issue in the future.

Dr. Brufsky said that "the advent and adoption of tomosynthesis around the United States in the coming years may make ultrasound screening redundant for dense breasts in the future."

Currently, an ultrasound is used to follow up on mammograms that may show a tumor. Tomosynthesis provides a 3-D picture of the breast but is not yet widely available.

Breast density, as the term implies, indicates how dense breast tissue is when seen on a mammogram. Fatty tissue is more translucent, while fibroglandular tissue looks opaque, or dense.

Fibroglandular tissue includes the milk ducts and supporting structures of the breast. Neither type of tissue includes muscles.

In a mammogram, fatty tissue tends to look darker, while dense breast tissue looks lighter or white.

Dense breast tissue can hide or mask cancers in the breast, according to Dr. Rhodes and team. It has also been found to increase the future risk of breast cancer.

Dense breasts are fairly common among US women. More than half of women younger than 50 have dense breasts, as do at least one third of older women, according to Dr. Rhodes and team.

Dense breast tissue can also cause false negative and false positive mammogram results.

Dr. Rhodes and colleagues surveyed over 2,000 women aged 40 to 74. Around 65 percent of the women returned the surveys.

These researchers found that 58 percent of the women had heard of breast density. Forty-nine percent knew that breast density may affect mammogram results and breast cancer detection. Fifty-three percent knew that breast density can be tied to an increased risk of breast cancer.

White women were more likely than other groups to be aware of issues related to breast density. Women with higher incomes and higher education also had higher levels of awareness.

Connecticut survey respondents were more likely to have discussed breast density with a health care professional than those from other states. Women from Connecticut were also more likely to know that dense breast tissue could mask breast cancer on a mammogram.

Connecticut passed legislation mandating education about breast density in 2009.

This study was published March 2 in the Journal of Clinical Oncology.

Funding for this study came from the Mayo Clinic Center for Individualized Medicine and the Mayo Foundation for Medical Education and Research. Conflict of interest disclosures were not available at the time of publication.

Review Date: 
March 3, 2015
Last Updated:
March 4, 2015