Although breast cancer is still more common in women above age 40, a growing number of younger women are receiving a diagnosis. An estimated 10% of women with breast cancer are under age 45, according to the Centers for Disease Control and Prevention.
The risk for breast cancer at a younger age is more pronounced in younger Black women; a study from the Washington University School of Medicine in St. Louis found that Black women between the ages of 20 and 29 had a 53% higher risk compared with white women of the same age.
Breast cancer is the most common type of cancer diagnosed in women ages 15 to 39. The increase is primarily fueled by diagnoses of estrogen-receptor positive tumors, says Dr. Kenneth W. Jones, a general surgeon at Ascension St. Vincent's in Jacksonville.
However, researchers aren’t entirely clear why breast cancer is increasing among the younger population. Women who are under age 40 are 40% more likely to die from their cancer compared with women over age 40, according to the Breast Cancer Research Foundation.
The U.S. Preventive Services Task Force currently recommends that breast cancer screening begin at age 40, but a breast cancer risk assessment can and should be done at age 25, Jones says. For women who are in the high-risk category, a breast MRI and a mammogram are recommended every year beginning at age 30, according to the American Cancer Society. Women in that category have a 20% to 25% lifetime risk of developing breast cancer.
“Increasingly, understanding one’s risk of breast cancer for a more nuanced approach to screening is seen as best practice,” says Dr. Karen C. Daily, a professor of medicine in the Division of Hematology and Oncology at the University of Florida College of Medicine in Gainesville.
When breast cancer occurs in younger women, preserving fertility, contraception during treatment, and timing interruptions in treatment to attempt pregnancy can be major concerns, Daily says. “Financial consequences are especially impactful for younger women who are missing work for treatment and recovery in addition to incurring health care expenses,” she says.
Sexual health and changes in appearance also are concerns that affect both younger and older breast cancer patients, Daily says.
Limiting alcohol, maintaining a healthy weight, and regular physical activity all can help lower breast cancer risk, Daily says. So can eating more plant-based foods and quitting smoking, Jones says. “Mothers should breastfeed if possible, and women should limit hormone therapy after menopause,” he adds.