Dr. Anne Marie McCarthy, Ph.D., is focused on developing new ways to identify women who are at a high risk for aggressive breast cancer, especially individuals from historically marginalized populations.
“More research is needed to help us predict which people are going to get breast cancer,” Dr. McCarthy said. “Family history is a very important and strong risk factor for breast cancer. However, many people who get breast cancer don’t have a family history. I’m interested in using new risk factors to do a better job of identifying people who are most in need of screening.”
As an assistant professor of epidemiology at the Perelman School of Medicine at the University of Pennsylvania, Dr. McCarthy aims to integrate genetics into clinical care and to develop tailored prevention strategies based on individual patient risk. She identified inherited genetic mutations and breast density as two risk factors where more research is needed.
“Knowing that you have a genetic mutation can cause worry and anxiety, but it also gives you information that can help you take more steps to reduce your risk.”
In the U.S., 5-10% of breast cancers are related to a known inherited gene mutation. BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the most well-known genes linked to breast cancer. About 1 in 400 people have a BRCA1/2 gene mutation in the U.S. By age 70, the chance of developing breast cancer is 50-65% for women who have a BRCA1 mutation and 50-55% for women who have a BRCA2 mutation.
“People with these mutations are recommended to take extra steps, which may include more frequent screening and breast MRI in addition to mammography,” Dr. McCarthy said. “Some people with BRCA1/2 mutations may choose to have their breasts or ovaries removed to reduce their risk or take drugs such as tamoxifen.”
“Knowing that you have a genetic mutation can cause worry and anxiety, but it also gives you information that can help you take more steps to reduce your risk,” she continued.
Breast Density and Risk
Dr. McCarthy also believes more awareness is needed for the link between breast density and risk. Breast density compares the area of breast and connective tissue seen on a mammogram to the area of fat. Women with dense breasts are four to five times more likely to get breast cancer than women with fatty breasts.
“Women who have highly dense breasts are more likely to get breast cancer, and they’re also more likely to have a cancer missed on a mammogram, Dr. McCarthy said. “Mammography is very effective at reducing breast cancer mortality, but like all tests, it’s not perfect.”
“There have been some clinical trials showing that for people with the highest category of breast density or extremely dense breasts, having a breast MRI improves their breast cancer detection and reduce the number of missed cancers.”
Dr. McCarthy is partnering with Despina Kontos, Ph.D., a computer scientist and Professor of Research Radiology at Penn, to develop imaging biomarkers for mammograms.
“Her lab has computer scientists who take the mammogram image and run computer algorithms to pick out which women might be at higher risk for breast cancer,” Dr. McCarthy explained. “We’re hoping these newer imaging biomarkers might help us identify risk beyond what we’re able to do now.”
Dr. McCarthy noted that radiologists typically determine how dense breasts are by examining the mammogram and rating breast density on a four-level scale. Women in the top two categories of breast density have a higher risk of developing breast cancer.
“There have been some clinical trials showing that for people with the highest category of breast density or extremely dense breasts, having a breast MRI improves their breast cancer detection and reduce the number of missed cancers,” she said.
A breast MRI uses magnetic fields to create an image of the breast. In some cases, doctors may recommend a breast MRI as a follow-up test if other tests can’t rule out breast cancer.
“Some states are also legislating for insurance coverage of supplemental breast cancer screening with MRI,” Dr. McCarthy said. “Depending on what state you live in, and if you have extremely dense breasts, you might be able to qualify for breast MRI in addition to mammography.”
Access to supplemental and diagnostic breast imaging is not just limited by insurance coverage, but also by affordability. A Komen-commissioned study found that costs to patients range from $234 for a diagnostic mammogram to more than $1,021 for a breast MRI, which may prevent people from getting the imaging they require. Komen’s Center for Public Policy is leading state and federal advocacy efforts to pass policies that would remove financial barriers for people needing diagnostic and supplemental breast imaging services.
While Dr. McCarthy noted that improvements in early detection and treatment have contributed to a 43% decline in breast cancer mortality in the U.S. between 1989-2020, not all patients have benefited equally.
“Black women in the U.S. have about a 40% higher breast cancer mortality than white women, and that disparity has really stayed stable over time,” Dr. McCarthy said. “We believe that’s partly due to systemic racism and challenges to getting access to care.”
“In addition, there might be some risk factors that are more important for one population than another that we’re not considering to the extent that we need to,” Dr. McCarthy continued. “In my work at Penn, we’re really focused on personalized screening for diverse populations to make sure that the recommendations we’re making work well for all people at all levels of risk.”
Your breast health journey starts with knowledge. Whether you’re concerned about your risk of breast cancer, have a history of breast cancer or other cancers in your family, or are curious about genetic testing, the first step is learning more about risk. Learn more about breast risk factors on Komen.org.
