Most women did not feel confident they knew what actions could mitigate breast cancer risk, leading researchers to the conclusion that comprehensive education about breast cancer risks and prevention strategies is needed.
The study was published earlier this year in JAMA Network Open.
“Forty [percent] to 50% of women who undergo mammography fall into the two highest breast density categories,” said the study’s lead author Christine Gunn, PhD, of the Dartmouth Institute for Health Policy and Clinical Practice, N.H. “Breast cancer risk increases from 1.2-4.0 times depending on the level of breast density. By comparison, a first-degree family history of breast cancer, particularly in premenopausal women, confers a two-fold higher breast cancer risk.”
Dr. Gunn’s study is based on a survey of 2,306 women (between 40 and 76 years old) that was conducted between 2019 and 2020. The goal was to determine how well women understood cancer risks associated with dense breast tissue. The final analysis included 1,858 women (9% Asian, 27% Black, 14% Hispanic, 43% White, and 7% other race or ethnicity).
Breast density was thought to be a greater risk than not having children, drinking daily, and having had a prior breast biopsy, according to 52%, 53%, and 48% of respondents, respectively. Breast density was believed to be a lesser breast cancer risk than having a first-degree relative with breast cancer by 93% of women, and 65% of women felt it was a lesser risk than being overweight or obese.
Of the 61 women who completed follow-up interviews, 6 described breast density as a contributing factor to breast cancer risk. And, 17 women did not know whether it was possible to reduce their breast cancer risk.
Doctors must notify patients in writing
Breast tissue falls under one of four categories: fatty tissue, scattered areas of dense fibroglandular tissue, many areas of glandular and connective tissue, or extremely dense tissue. The tissue is considered dense if it falls under heterogeneously dense or extremely dense, and in those cases, follow-up testing with ultrasound or MRI may be necessary. This is important, Dr. Gunn said, because dense tissue can make “it harder to find cancers because connective tissue appears white on the mammogram, potentially masking tumors.”
Prior studies have found that many clinicians are uncomfortable counseling patients on the implications of breast density and cancer risk, the authors wrote.
However, under the Mammography Quality Standards Act, which was updated on March 10, the Food and Drug Administration requires that patients be provided with a mammography report summary that “identifies whether the patient has dense or nondense breast tissue.” The report, which should be written in lay language, should also specify the “significance” of the dense tissue.
While some states mandate notification regardless of the density level, most only notify women if heterogeneously dense or extremely dense tissue has been identified, Dr. Gunn said. But the rules are inconsistent, she said. In some facilities in Massachusetts, for example, women may receive a mammography report letter and a separate breast density letter. “For some, it has been really confusing. They received a letter saying that their mammography was normal and then another one saying that they have dense breasts – resulting in a lot of uncertainty and anxiety. We don’t want to overly alarm people. We want them to understand their risk,” she said.
Breast density can be considered among other risk factors, including alcohol use, obesity, diet, parity, prior breast biopsy, and inherited unfavorable genetic mutations. “If the total lifetime risk is above 20%, that opens up further screening options, such as a breast MRI, which will catch more cancers than a breast mammogram by itself,” Dr. Gunn said.
“The challenges for physicians and patients around collecting and understanding breast density information in the context of other risk factors can potentially lead to disparities in who gets to know their risk and who doesn’t,” Dr. Gunn said. It would be possible, she speculated, to create or use existing risk calculators integrated into medical records and populated with information gathered in premammography visit questionnaires. Ideally, a radiologist could hand the patient results in real time at the end of the mammography visit, integrating risk estimates with mammography findings to make recommendations.
This study was supported by grant RSG-133017-CPHPS from the American Cancer Society.