October is Breast Cancer Awareness Month, a time to highlight advances in early detection and research that save lives. Scientists at the University of Hawaiʻi Cancer Center are leading efforts to improve breast cancer screening and risk modeling for Hawaiʻi’s diverse population.
John Shepherd, chief scientific officer and director of the Hawaiʻi and Pacific Islands Mammography Registry, shares what people should know about breast density, a key factor in both cancer risk and detection. Shepherd also explains a new federal mandate requiring that every person undergoing mammography in the U.S. be informed about their breast density.
Q: What exactly is breast density, and why does it matter?
Breast density can be thought of in two ways: biologically and practically. Biologically, it refers to having more fibrous tissue in the breast, which makes it stiffer. The more of that type of tissue a woman has, the higher her risk of breast cancer. Practically speaking, we detect breast density through mammograms. On a mammogram, dense tissue appears white—and so does cancer. That means the denser the breast, the harder it is for radiologists to see potential cancers.
Q: What factors influence breast density?
Some factors can’t be changed, like genetics. For instance, Native Hawaiian and Asian women generally have higher breast density than Caucasian or Hispanic women. Other factors are lifestyle-related. Body mass index, smoking and having children can all influence density. Diet also plays a role. Women who smoke tend to have higher breast density, while those who have had children usually have lower density.
Q: What’s changing with the new mammography regulations?
A new law—an update to the Mammography Quality Standards Act—now requires that mammography reports sent to patients include information about breast density. In the past, a report might have said something simple like, “We don’t see cancer. Come back next year.” Now it must include wording that tells women if they have dense breast tissue and that it can make cancers harder to detect. The goal is to help women understand their screening results and talk with their healthcare providers about their individual risk.
Q: What can women do if they learn they have dense breast tissue?
One practical step is to use online risk assessment tools. You can enter your age, breast density, and other factors to get an overall picture of your breast cancer risk. Not all women with dense breasts are at high risk, but knowing your risk can guide decisions about screening and prevention. Regular mammograms, breast self-exams and discussions with your doctor are key to maintaining breast health.
Q: Why is this issue especially important in Hawaiʻi?
Because Native Hawaiian and Asian women generally have higher breast density, cancers may be more easily masked in mammograms here. This means women in Hawaiʻi might benefit from supplemental screening such as ultrasound or MRI. Understanding these differences helps ensure that all women—especially those in higher-risk groups—get the care and screening they need.
Watch the full interview with John Shepherd.
