Although breast cancer incidences among women ages 20 to 49 have continually increased over the past two decades, breast cancer deaths among women in this age group have dropped significantly since 2010, according to new research recently presented at the American Association for Cancer Research’s 2025 Annual Meeting.
Led by Adetunji Toriola, professor of surgery at Washington University in St. Louis, the research team examined data regarding 11,661 breast cancer deaths among women aged 20 to 49 between 2010 and 2020. Overall, incidence-based breast cancer mortality declined from 9.7 deaths per 100,000 women in 2010 to just 1.47 deaths per 100,000 women in 2020.
Among different subtypes of the disease, luminal A had the most pronounced decline, followed by triple-negative breast cancer. However, the 10-year survival rate for these different subtypes varied by age. For women ages 40 to 49, luminal A had the highest 10-year survival rate, while luminal B had the highest survival rate for women ages 20 to 39.
While breast cancer deaths have declined among women of all racial backgrounds, the study found notable racial disparities in incidence-based breast cancer mortality. Black women had the highest mortality rates in both 2010 and 2020, at 16.56 and 3.41 deaths per 100,000 women, respectively. In comparison, the mortality rates for White women in 2010 and 2020 were 9.18 and 1.16 deaths per 100,000 women, respectively. Declines in breast cancer deaths became most pronounced for Black women in 2016, for Asian and Pacific Islander women in 2013, for Hispanic women in 2017, and American Indian and Alaska Native women in 2018.
According to Dr. Toriola and his colleagues, the drastic declines in breast cancer mortality seen after 2016 are likely due to advancements in treatment options, greater uptake of precision medicine, and expanded access to care and screening for middle-aged women.
“We must continue to perform impactful research to ensure further reduction in breast cancer mortality, including research into understanding the tumor biology and molecular mechanisms driving carcinogenesis and treatment response in younger women,” said Dr. Toriola. “Additionally, we must encourage and provide access to population-based screening in women ages 40-49 and targeted screening in younger high-risk women, and advocate for access to high-quality treatment and care for all women.”