A cohort study assessing breast cancer incidence trends across racial and ethnic groups in the United States has revealed significant differences in how rates have changed over the years in different subgroups of patients.

Researchers analyzed data from 1,123,658 females across 22 U.S. cancer registries from 2010 to 2019 and found that while the overall incidence rate of breast cancer increased by 0.5% per year, certain racial and ethnic groups experienced disproportionately higher increases. They published their findings in JAMA Network Open.

Investigators reported that breast cancer incidence increased annually by 1.4% among Hispanic females, 1.9% among non-Hispanic American Indian or Alaska Native females, and 2.1% among non-Hispanic Asian or Pacific Islander females. In contrast, non-Hispanic Black females and non-Hispanic White females had more modest increases of 0.8% and 0.5%, respectively. 

The researchers also included molecular subtypes of breast cancer in their analysis, and found that triple-negative breast cancer (TNBC) showed the most significant increases in incidence. Among participants aged 65 years or older, the incidence of TNBC increased by 2.3% per year for Hispanic women, 5.5% per year for non-Hispanic Asian or Pacific Islander women, and 4.3% per year for non-Hispanic Black women. Notably, the incidence of TNBC remained unchanged among non-Hispanic White females during the same period.

These findings highlight the growing disparities in breast cancer incidence, particularly in minority populations, and underscore the need for targeted interventions and further research with a focus on understanding why certain subgroups are more susceptible to aggressive forms of the disease, noted the authors.

No conflicts of interest were mentioned in the study.