A new study recently presented at the San Antonio Breast Cancer Symposium found that patients in economically and racially/ethnically marginalized neighborhoods are more likely to present with breast cancer at later stages of the disease.
“ through several mechanisms, such as access to health care, particularly through limited breast cancer mammographic screening,” said the study’s author, Neha Goel, MD, an assistant professor of surgery at the University of Miami.
The findings are based on an analysis of data from the neighborhood indicator called the Index of Concentration at the Extremes, a database that focuses on the distribution of concentrations of privilege and deprivation, rather than comparing individual or household levels. This is important because growing concentrations of extreme wealth and extreme poverty are becoming increasingly common, and these are not properties discernible by measures by individuals or households. The indicator considers concentration of privilege and deprivation independently, unlike typical models that combine these factors. Doing so reduces bias that can occur in statistical models where these two factors can influence one another. “It brings subtle social inequalities and polarization to the forefront and maps a critical dimension of social inequality,” Dr. Goel said.
Researchers defined structural racism based on its effects, such as separation of marginalized economic and racial/ethnic groups, as well as classism that occurs as a result of discriminatory housing policies over decades. The American Medical Association defines structural racism as the “totality of ways in which societies foster racial discrimination through mutually reinforcing systems of housing, education, employment, earnings, benefits, credit, media, health care and criminal justice.” It considers racism, structural racism, and unconscious biases within medical research and health care delivery to be public health threats. The AMA calls for educational and continuing medical education programs to promote an understanding of all forms of racism, and methods for preventing or reducing the health effects of racism.
The final analysis included 6,145 patients (52.6% Hispanic, 26.3 White, and 17.2% Black) who were treated for breast cancer between 2005 and 2017. At 45.2%, nearly half of participants were privately insured.
Five models were created comparing the likelihood of being diagnosed with a more advance stage tumor (stage 3-4 vs. stage 1-2) between the most disadvantage quartile and the most advantaged group quartile. They found significant relationships for low versus high economic segregation for both the most disadvantaged quartile (odds ratio, 1.36; P < .05) and the second-most disadvantaged quartile (OR, 1.43; P < .05); low-income Black versus high-income White patients in both the most disadvantage quartile (OR, 1.55; P < .05) and the second-most disadvantaged quartile (OR, 1.44; P < .05); Hispanic versus non-Hispanic ethnicity in the most disadvantaged quartile (OR, 1.32; P < .05), and low-income Hispanics versus high-income Whites in both the most disadvantaged quartile (OR, 1.43; P < .05) and the second-most disadvantaged quartile (OR, 1.56; P < .05).
Black patients were more likely to be diagnosed with triple-negative breast cancer than White patients (25.1% vs. 12.5%; P < .001).
The findings suggest that both economically disadvantaged patients and those in racially or ethnically marginalized neighborhoods had a greater probability of having later-stage disease at diagnosis. The researchers controlled for age, insurance status, tumor subtype, and comorbidities like diabetes, coronary artery disease, and hyperlipidemia.
“This study adds insight to a growing body of literature that demonstrate how the ecological effects of structural racism – expressed through poverty and residential segregation – shape cancer outcomes across patients of all races [and] ethnicities,” Dr. Goel said.
Dr. Goel has no relevant financial disclosures.