Many Women at High Risk of Breast Cancer Do Not Undergo Supplemental Screening

A new study suggests that it is important to consider other risk factors for breast cancer beyond breast density. The results appeared online in the journal CANCER.

Dense breast tissue contains a higher proportion of fibrous tissue than fat, making it a risk factor for breast cancer. Many states require that women with dense breasts receive notification following a mammogram so they can elect whether or not to undergo supplemental ultrasound screening for better cancer detection. This analysis sought to weigh the benefits versus the harms of doing so.

In this study, lead researcher Brian Sprague, PhD, of the University of Vermont Cancer Center, and his colleagues assessed 38,166 supplemental ultrasounds and 825,360 screening mammograms without supplemental ultrasounds during 2014–2020 at 32 U.S. imaging facilities within three regional registries of the Breast Cancer Surveillance Consortium.

The study found that over 95% of supplemental ultrasounds were performed in women with dense breasts. By comparison, about 42% of mammograms without additional screening were performed in women with dense breasts.

Among women with dense breasts, a high risk of interval invasive breast cancer was present in 23.7% of women who underwent ultrasounds, compared with 18.5% of women who had mammograms without additional imaging.

These results suggest that ultrasound screening was highly targeted to women with dense breasts, however, only a modest proportion of these women were at high risk of mammography screening failure. A similar proportion of women who received only mammograms were at high risk of mammography screening failure.

“Among women with dense breasts, there was very little targeting of ultrasound screening to women who were at the highest risk of a mammography screening failure. Rather, women with dense breasts undergoing ultrasound screening had similar risk profiles to women undergoing mammography screening alone,” said Dr. Sprague. “In other words, many women at low risk of breast cancer despite having dense breasts underwent ultrasound screening, while many other women at high risk of breast cancer underwent mammography alone with no supplemental screening.”