Only 20 percent of women know that dense breasts reduce the sensitivity of mammography for detecting tumors, and even fewer are aware that dense breast tissue is a risk factor for malignancy, according to a new survey of Virginia women (J Am Coll Radiol 2017;14:34-44).
“Breast density is a relatively young topic in the public eye, so I wasn't surprised that many women weren't aware of [it] as a breast cancer risk factor,” said Jennifer A. Harvey, MD, Professor of Radiology in the Department of Radiology and Medical Imaging at the University of Virginia in Charlottesville.
Women also need to know that the denser the breast tissue, the higher the likelihood that cancer may not be seen on a mammogram, explained Harvey. If patients feel a lump in their breast or notice any abnormality in their breast tissue, they should notify their doctor, even if they've just had a mammogram.
Providing well-written and informative breast density notification letters and educating patients and their referring physicians about breast density and supplemental screening options can help ensure women receive the care they need.
Breast Density Study Details
Harvey and her colleagues conducted a random phone survey of 1,024 Virginia women ages 35-70 and performed bivariate and multivariate analyses. At the time of the study, Virginia was among 27 states requiring radiologists to inform patients about their breast density.
Overall, the researchers found that only one in 5 women knew dense breasts reduced the sensitivity of mammograms to find tumors. Moreover, just one in 8 women were aware breast density is a risk factor for breast cancer.
While 75 percent of women reported being somewhat or very familiar with breast cancer risk factors, only 0.8 percent mentioned breast density as a risk factor.
Researchers found the strongest factor in knowing about breast density and its relationship with breast cancer was whether a health care provider had informed a woman about the density of her breasts.
About 39 percent of women reported their health care provider had informed them about their breast density. Nearly 52 percent of women who had undergone a mammogram in the past 12 months said they had been informed about having dense breast tissue.
“About the right number of women who had a mammogram in the past year knew they had dense tissue, but the implications of having this dense breast tissue don't seem to be coming across,” said Harvey.
Women with lower education levels and African-American women had less understanding of breast density. Notably, while the Ashkenazi Jewish population tends to have higher education levels, women in this group were less aware of breast density reducing the sensitivity of mammograms and as a risk factor for breast cancer. The reasons behind these findings in the Ashkenazi populations were unclear, Harvey noted.
Letters to Inform Patients Have Limitations
The letters used to inform patients about their breast density appear to have some limitations. For example, prior research found wide variation in the dense breast notification content of 23 states (JAMA 2016;315(16):1786-1788). Letters were written at high school literacy level or above and had poor understandability. Moreover, the letters were written at a literacy level that did not adequately reflect the states' average literacy levels.
Standardized language in these breast density notifications that is proven to accurately convey information in a way comprehensible for women at all literacy levels, and in various languages, would be ideal, said the JAMA research letter's lead author Nancy Kressin, PhD, Professor in the Department of Medicine and Director of the Health/Care Disparities Research Program at Boston University School of Medicine.
Every state that has a density notification law has letters that are written a little differently from one another, noted Harvey. National legislation ensuring the messaging is uniform might be beneficial for patients and health care providers, she said.
While scientific evidence shows that having dense breast tissue poses a small increased risk of cancer and that dense breast tissue reduces the sensitivity of mammography, it “is not yet sufficient to guide what women with dense breasts should do, as far as obtaining supplemental screening,” said Kressin, citing the U.S. Preventive Services Task Force.
Current guidelines suggest women and their clinicians make decisions about screening based on a woman's overall risk of breast cancer, including breast density as well as other factors such as family history, added Kressin. “My hope is that the letters could include all of this information, so that women understand the whole picture of their breast cancer risk, including their breast density,” she said. Information about personalized risk can help women make appropriate screening decisions.
Many women are choosing to have additional screening, most typically ultrasonography, said Harvey. However, insurance coverage for screening ultrasound still varies around the country.
Whether radiologists recommend supplemental ultrasound depends on the facility and state in which they live, said Jiyon Lee, MD, Clinical Associate Professor of Radiology at NYU's Perlmutter Cancer Center.
Some breast radiologists may be more likely to suggest a follow-up ultrasound in the setting of extremely dense tissue, other added risk factors, and baseline exams that do not have comparison studies, according to Lee.
With that said, radiologists also need to be diplomatic about suggesting an ultrasound because it is a supplemental test that patients or their referring physicians may choose to forego, noted Lee. Additional imaging techniques such as ultrasound are “opt in tests, not standard-of-care replacements of mammography,” she explained.
Radiologists are also turning to newer technologists such as tomosynthesis to evaluate dense breasts, said Lee. This technology can pick up more cancers and decrease false-positive recalls related to superimposed tissue compared to standard mammography.
MRI may be considered in women with dense breasts if they are higher risk overall. For example, women with BRCA mutations might be eligible for MRI.
In addition, contrast-enhanced digital mammography, molecular breast imaging, and breast specific gamma imaging are used in various facilities. “Again, in a supplemental role to screening mammography,” said Lee, adding that these imaging methods show how breast tissue is functioning, not just its anatomy. “They're not meant to be stand alone or primary tests.”
Based on her study findings, Harvey suggests specifically targeting education about breast density and cancer risk toward the African-American community, as well as the Ashkenazi Jewish population in Virginia.
Lee ensures that patients understand dense breasts contain normal fibroglandular tissue, “part of the range of normal in women.” Any supplemental screening test has the potential to pick up a few more cancers, along with other findings that need to be evaluated, she noted.
Lee often recommends patients and professionals visit densebreast-info.org for more information. Additionally, she finds the Society of Breast Imaging and the American College of Radiology to be valuable sources for physician education.
“We can focus on the education of women, but we also need to educate health care providers,” said Harvey. While notification letters encourage women to talk to their health care providers, their referring doctors often are unsure of what to advise. Providers need to know how to best explain the implications of having dense breast tissue, the chances of having a missed cancer, and what other screening options are available, Harvey concluded.
Heather Lindsey is a contributing writer.