On mammogram, women with a breast density 75% or higher have a risk of breast cancer that is four or five times higher than those with little density or none at all. Mammographic density is the amount of white or radiodense area compared to the amount of grey or radiolucent area on a mammogram, and it's one of the strongest biomarkers and predictors of breast cancer risk.
Carol J. Fabian, M.D., professor of medicine in the division of clinical oncology and director of the Breast Cancer Prevention Center at the University of Kansas Medical Center, said "The cancer research community is always looking for new methods to better define short-term risk to supplement the known risk factors for breast cancer like family history, genes associated with hereditary breast cancer, reproductive variables and age," adding, "Modifiable risk biomarkers like mammographic density are increasingly being used in small early phase prevention trials to help us decide which interesting strategies should be carried further into very large Phase III studies with cancer incidence as an endpoint." He explained "These abstracts strengthen the observation that high breast density is associated with increased risk for breast cancer, and they strengthen the hypothesis that under some conditions, reducing breast density may be associated with reduced risk for breast cancer,"
According to a study of 19,924 women above the age of 35, and had a mammogram at the Mayo Clinic. Celine M. Vachon, Ph.D., associate professor of epidemiology in the College of Medicine at the Mayo Clinic, Rochester, Minn, leader of the study and colleagues evaluated the changes in breast density over time along with the risk of breast cancer using the Breast Imaging-Reporting and Data System (BI-RADS) to collect data. It was found that "Women who experienced a reduction of at least one density category over the six years were at reduced risk of breast cancer (28 percent lower risk) compared to those whose density was unchanged," Vachon said. "And, women who increased by one or more BI-RADS categories over the time period had suggestion of increased risk." He explained further more "A decrease in breast density appears to be associated with a lower breast cancer risk, and importantly, this result takes into account baseline breast density, as well as changes in BMI that occurred between mammographic assessments,"