TOPLINE:

A national cohort study found that the incidence of triple-negative breast cancer (TNBC) is highest among Black women living in the most socioeconomically disadvantaged neighborhoods, and the incidence largely decreased incrementally as neighborhood conditions improved. The findings suggest that social and environmental conditions could contribute to downstream BC survival disparities observed among Black women.

METHODOLOGY:

• TNBC disproportionately affects non-Hispanic Black women and prior regional studies have suggested that those exposed to higher levels of social adversity — which encompasses chronic social, economic, and environmental stressors — have a greater likelihood of developing TNBC.
• The current study assessed this association between social adversity and TNBC incidence in a national cohort of Black women.
• Researchers analyzed Surveillance, Epidemiology, and End Results 18 data from 2006 to 2020, using the Yost Index as a measure of socioeconomic status.
• The analysis involved 13,340 Black women with stages I-IV TNBC (mean age, 58.1 years) diagnosed from 2010 to 2020. Women were divided into five social adversity categories from most (group 1) to least (group 5) disadvantaged.
• The primary outcome was age-adjusted incidence of TNBC per 100,000 persons. Researchers calculated incidence rate ratios (IRRs), comparing TNBC incidence in the most disadvantaged quintile to those in the other four social adversity groups.

TAKEAWAY:

• The age-standardized incidence rate of TNBC was highest in the highest social adversity category (19.3 per 100,000 persons), and declined across social adversity groups, reaching 17.2 per 100,000 in the least disadvantaged group.
• Women in neighborhoods with the least social adversity were less likely to develop TNBC than those in the most disadvantaged group (IRR, 0.89; 95% CI, 0.84-0.95).
• The intermediate groups also had a lower incidence of TNBC than the most disadvantaged group (IRR, 0.93 for group 2; IRR, 0.94 for group 3); however, those in group 4 (the second highest socioeconomic status neighborhood category) had about the same incidence of TNBC as the most disadvantaged group (19.0 and 19.3 per 100,000 persons, respectively; IRR, 0.98; 95% CI, 0.93-1.04).

IN PRACTICE:

“This cohort study shows that high social adversity is associated with a high incidence of TNBC among Black women,” the authors concluded, adding that the “findings suggest potential social (epi)genomic and gene-environment interactions between social adversity and TNBC development in Black women.”

SOURCE:

The study, led by Alexandra Hernandez, MD, MPH, University of Miami Miller School of Medicine, Miami, was published online in JAMA Network Open.

LIMITATIONS:

The study was limited by the absence of individual-level data such as BRCA1 variant status, family history, and reproductive factors, which may have introduced residual confounding and potential for ecologic fallacy. Additionally, the Yost Index used in the study did not fully capture neighborhood-level social adversity.

DISCLOSURES:

The study was supported by grants from the National Cancer Institute of the National Institutes of Health and Breast Cancer Research Foundation, an American Surgical Association fellowship award, an American Society of Clinical Oncology career development award, a V Foundation award, and a Society of Surgical Oncology Clinical Investigators award. One author reported receiving grants from the National Cancer Institute during the conduct of the study.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.