From 2010 to 2020, breast cancer deaths among women aged 20 and 49 decreased significantly in all breast cancer subtypes and racial/ethnic groups, with a decrease marked from 2016, according to a surveillance data analysis, epidemiology and the final results (SEER) presented in the American Cancer Research Association (AACR) Annual Meeting 2025 April of April.
The incidence rates of breast cancer in women aged 20 to 49 have increased in the last 20 years in most racial and ethnic groups, but few studies have examined mortality data for patients in this age group, according to Adetunji Toriola, MD, PHD, MPH, profess The University of Washington of Medicine.
“Understanding recent mortality trends will allow us to evaluate progress over the years and inform where to direct resources to reduce cancer load in this age group,” said Toriola, who presented the study.
Toriola and Colleagues Analyzed Data from the Seer Program 17 Registry, which included data on 11,661 Breast cancer Deaths Among Women Ages 20-49 Between 2010 and 2020. They Evaluated Breast Cancer Incident-Based Mortity By Race and Molecular Subtypes-Luminal Luminal A, Luminal B, Luminal B, Luminal B, Luminal Epidermal Growth Receiver Factor 2 (HER2) -Inriched, and Triple-Negative Breast Cancer-and identified Differences in Trends use of annual percentage changes (APC). In addition, they carried out relative survival analysis in examining the 10 -year survival rate for each group and subtype.
In all racial/ethnic subtypes and groups, incidence-based mortality decreased from 9,70 per 100,000 women in 2010 to 1.47/100,000 in 2020. Luminal A had the most pronounced decrease between the four subtypes, with a decrease during the entire period of time and the greatest fall in 2017 (-32.88% APC). Triple negative breast cancer followed a similar trend, with 2018 marking its greatest decline (-32.82% APC).
Although the decrease in incidence -based mortality was the largest for luminal A in general, the relative survival of 10 years for women with this subtype of breast cancer varied according to age. Among women from 40 to 49 years, Luminal A had the highest survival of 10 years, while among women aged 20 to 39, luminal A (78.3%) had a lower survival to 10 years than B (84.2%).
“This was unexpected since Luminal A is generally the less aggressive subtype with the most favorable forecast,” Toriola said. “This requires confirmation in other studies, but it can suggest that luminal A tumors in women from 20 to 39 years can represent a more biologically heterogeneous and potentially aggressive subgroup.”
While incidence -based mortality decreased for each of the racial/ethnic groups, non -Hispanic black women had the highest mortality based on the incidence both in 2010 (16.56/100,000) and in 2020 (3.41/100,000) and non -Hispanic white women had mortality based on the lowest incidence in 2010 (9.18/100,000) and 2020) (1.16/100,000). The decreases became more pronounced for non-Hispanic black women in 2016 (-24.15% APCs), for non-Hispanic/Pacific islands in 2013 (-18.46% APC), for Hispanic women in 2017 (-30.15% APC) and for American and native Indian women of Alaska in 2018 (-47.97% APC).
The 10 -year relative survival analysis found that non -Hispanic black women had the worst survival results, while non -Hispanic White Women and Asian island/of the Pacific not Hispanic were the best.
“We have advanced huge to reduce the mortality of breast cancer in young women, but there are still opportunities for improvements, especially in relation to the elimination of disparities,” Toriola said.
Toriola explained that the most drastic decreases observed after 2016 probably reflect advances in treatment options, greater absorption of precision medicines and expanded access to care and detection in women from 40 to 49 years. For example, he mentioned how the broader adoption of CDK4/6 inhibitors and the optimization of endocrine therapy, which began to receive the approval of the FDA and the clinical adoption between 2015 and 2016, probably performed key roles in improving mortality rates for the cancers of positive hormonal receptors, her2, including the inclusion of A. Luminal A. Luminal A. Luminal A. Luminal A.
“We must continue to carry out shocking research to guarantee a greater reduction in breast cancer mortality, including research on the understanding of tumor biology and molecular mechanisms that drive carcinogenesis and the response to treatment in younger women,” Toriola said. “In addition, we must encourage and provide access to population detection in women from 40 to 49 years and an examination in younger women at high risk, and advocate access to high quality treatment and care for all women.”
The key limitations of this study include a limited follow -up time and a relatively lower number of breast cancer deaths in some racial/ethnic groups.
The Washington University Foundation provided funds for this study. Toriola does not declare conflicts of interest.