By Kara Britt, Monash University; Honor Joy Hugo, Queensland University of Technology; Jennifer Stone, University of Western Australia; John Hopper, University of Melbourne; Pallave Dasari, University of Adelaide; Rik Thompson, Queensland University of Technology, and Wendy Ingman, University of Adelaide
Women with higher breast density for their age are more likely to develop breast cancer. High breast density also makes it harder for doctors to detect breast cancer on a mammogram. But Australian women are not routinely tested for and told about their level of breast density when they undergo a mammogram.
A woman’s breasts are made up of dense breast tissue and fatty breast tissue. Almost 8% of women aged between 40 and 74 years have extremely high breast density. This means they have more connective tissue and less fat surrounding their glands.
Breast density can’t be determined just from looking at or physically examining the breasts; it’s measured from a mammogram, an X-ray of the breast. Breast density appears white or bright, while non-dense breast tissue appears dark.
Breast cancers also appear white on a mammogram. So having high breast density can mask or hide the cancer, making early detection more difficult. This is especially important because women whose breast cancers that are found within 24 months of a “clear” mammogram tend to have poorer outcomes.
Across the population, a woman has a 12.5% chance of getting breast cancer in her lifetime. Women who have high breast density for their age and body mass index (BMI) have a four to six-times higher risk of developing breast cancer in the future compared to women with low breast density.
We are a group of breast cancer scientists concerned that Australian women are not being made aware of the significance of breast density in the diagnosis and prevention of breast cancer. We want to start a conversation about what density is, even though we don’t yet have all the answers.