Breast Cancer Risk

Changes in Breast Density Over Time May Predict Breast Cancer Risk

“Women who experience a decrease in breast density over a six-year period may have a reduced risk of developing breast cancer compared to those whose breast density remains stable.

This study, led by Dr. Celine Vachon, an Associate Professor of Epidemiology at the Mayo Clinic in Rochester, aimed to investigate the connection between changes in breast density and the risk of breast cancer. The research involved over 19,000 women who had mammograms between 2003 and 2006 at the Mayo Clinic. These women were all over the age of 35 and had no prior history of breast cancer.

To explore the relationship between changes in breast density and breast cancer risk, the team analyzed data from over 200 breast cancer cases and nearly 2,000 cases of women who were cancer-free, randomly selected from the original group. They assessed breast density using the BI-RADS (Breast Imaging – Reporting and Data System) tool, which categorizes breast composition into different density levels. By comparing BI-RADS ratings from two different time points, they could evaluate changes in breast density over time.

The results showed that individuals with breast cancer were less likely to have experienced a decrease of at least one BI-RADS density category after their initial mammogram. Women who had a decrease of one or more density categories over a six-year period had a 28% lower risk of developing breast cancer compared to those with unchanged density. Conversely, women who experienced an increase in one or more BI-RADS density categories over time showed indications of an increased risk.

Additionally, the study highlights the potential of using DXA (dual-energy X-ray absorptiometry) as an alternative to mammograms for measuring breast density, especially in younger women. This is crucial to reduce radiation exposure in younger age groups while identifying candidates for targeted breast cancer prevention strategies.

DXA, commonly used to assess bone density and body composition, offers a lower-radiation option for measuring breast density. In a cross-sectional study, Gertraud Maskarinec, the lead author of the study, compared breast density measured by DXA with mammogram density in 101 women aged 30 and older who underwent standard mammograms. The results showed a strong correlation between the two measurement methods, indicating the potential for DXA to provide a safer alternative for assessing breast density in women.”