Along with breast density, body mass index (BMI) should be considered when identifying women who could benefit from supplemental imaging studies for breast cancer screening, researchers said.
Otherwise, the risks conferred by dense breast tissue are likely to be underestimated in Black women, and they are less likely to undergo additional testing, the researchers warn.
Black women with breast cancer have higher rates of more aggressive forms of the disease. Their breast cancers are also more often missed on mammograms and later diagnosed at advanced stages.
Dense breast tissue can mask a potential cancer and increase the chance it will go undetected on mammography. Radiologists determine a woman's level of breast density based on the ratio of nondense tissue to dense tissue on her mammogram. Slender women are more likely to have higher proportions of dense breast tissue.
In a study of more than 860,000 women published in Cancer Epidemiology, Biomarkers & Prevention, researchers found that Black women had the lowest prevalence of dense breasts but the highest prevalence of obesity, another risk factor for breast cancer.
Without consideration of body mass index, a given volume of dense breast tissue is less likely to trigger a breast density warning and less likely to lead to supplemental imaging in Black women, researchers found.
In many states, women must be notified if mammograms show high levels of breast density, but state laws do not consider other breast cancer risk factors, the researchers note.
"The goal of breast notification laws is to identify women who are at increased risk of breast cancer and might benefit from supplemental imaging," said study leader Dr. Karla Kerlikowske of the University of California, San Francisco.
"Incorporating breast density and BMI would better identify women with high breast density at risk of a missed or advanced cancer rather than using breast density alone," she said.
Read more about breast cancer screening on Reuters.com
