Low-Radiation Breast Screening Option

Breast density, a known risk factor for breast cancer, received lots of attention at the recent annual meeting of the American Association for Cancer Research (AACR). In a finding of particular interest to radiologists, one researcher suggested that dual energy X-ray absorptiometry (DXA) may provide a low-radiation alternative to mammography in evaluating breast density among young women.

Research has already indicated that women with a breast density of 75 percent or greater on a mammogram run a risk of breast cancer four to five times greater than women with little or no density. So it’s important to measure density in order to evaluate breast-cancer risk.

However, using mammography for that purpose among younger women carries an unacceptably high level of radiation exposure. So a study led by Gertaud Maskarinec, MD, PhD, professor of epidemiology at the Cancer Research Center of Hawaii at the University of Hawaii at Manoa, evaluated DXA as a density-measuring tool. The cross-sectional study among 101 women age 30 or older compared breast density as measured by both mammograms and DXA. The two different measuring methods produced results that matched.

DXA, often used to evaluate bone density and total body composition, is widely available in medical offices and is considered a low-radiation technique. Said Dr. Maskarinec:

This is not practice-changing at the moment, but it does present the potential for future studies to elaborate on DXA’s use as a new research tool in breast cancer prevention studies among adolescents and young women.

Here are some other findings presented at the AACR meeting, which took place April 17-21 in Washington, DC:

• Women whose breast density decreases over a six-year period apparently enjoy a corresponding reduction in the risk of developing breast cancer. Among the women studied, those whose density decreased by one Breast Imaging-Reporting and Data System (BI-RADS) category had a 28 percent lower risk of breast cancer than those whose density remained unchanged.
• Increased breast density seems to be associated with the already-reported increased cancer risk among postmenopausal women who use estrogen and progestin therapy (EPT). A study of about 900 women found that those receiving EPT showed a 24 percent increased risk of breast cancer, which was explained by increased breast density.

Unfortunately, researchers don’t yet know why breast density changes or even why it varies among women. Stay tuned for future studies.

Related seminar: A Practical Approach to Breast Imaging and Digital Mammography