A comprehensive analysis of U.S. cancer registry data has revealed concerning disparities in breast cancer incidence rates across racial and ethnic groups, with minority women experiencing disproportionately higher increases in recent years.
The study, published in JAMA Network Open, examined data from 1,123,658 women diagnosed with invasive breast cancer across 22 U.S. cancer registries between 2010 and 2019. While overall breast cancer rates increased by 0.5% annually, the impact varied significantly among different demographic groups.
Striking Disparities in Incidence Rates
Non-Hispanic Asian or Pacific Islander women experienced the highest annual increase at 2.1%, followed by non-Hispanic American Indian or Alaska Native women at 1.9%, and Hispanic women at 1.4%. In comparison, non-Hispanic Black and White women showed more modest increases of 0.8% and 0.5%, respectively.
The findings are particularly alarming given existing mortality disparities. Between 2015 and 2019, non-Hispanic Black women faced a 40% higher mortality rate compared to non-Hispanic White women, despite similar diagnosis rates.
Triple-Negative Breast Cancer Trends
Perhaps most concerning is the sharp rise in triple-negative breast cancer (TNBC) among older minority women. Women aged 65 and older showed dramatic increases in TNBC incidence:
- 5.5% annual increase among non-Hispanic Asian or Pacific Islander women
- 4.3% annual increase among non-Hispanic Black women
- 2.3% annual increase among Hispanic women
- No significant change among non-Hispanic White women
These trends are particularly worrisome as TNBC is known for its aggressive nature and limited treatment options.
Research Implications and Limitations
The study's lead researchers note that understanding these disparities is crucial for developing targeted interventions. "A current gap in knowledge is how breast cancer subtype–specific incidence rates vary by race and ethnicity and age over the past decade," they wrote, emphasizing the importance of tracking these changes.
However, the study faced several limitations. The analysis couldn't account for key breast cancer risk factors such as reproductive history, body mass index, and lifestyle factors. Additionally, the potential for misclassification in race and ethnicity data, which was extracted from medical records, could affect the findings' accuracy.
Future Directions
The researchers emphasize the urgent need for further investigation into the factors driving these disparities, particularly in aggressive subtypes like TNBC. Understanding these trends will be crucial for developing targeted public health strategies and improving outcomes across all demographic groups.
