Tumor Biology, Social Determinants Equally Contribute to Breast Cancer Disparities

Doctor talking to older black female patient.
Doctor talking to older black female patient.
Findings seen among women with estrogen receptor-positive, axillary node-negative breast cancer.

(HealthDay News) — Social determinants of health and tumor biology contribute roughly equally to racial disparities in cancer-related death among Black and White women with breast cancer, according to a study published online Feb. 16 in JAMA Oncology.

Kent F. Hoskins, M.D., from the University of Illinois at Chicago, and colleagues estimated the proportion of the Black-White disparity in breast cancer survival from estrogen receptor-positive, axillary node-negative breast cancer that is associated with adverse social determinants and high-risk tumor biology. The Surveillance, Epidemiology, and End Results Oncotype registry was used to identify 60,137 women diagnosed between 2004 and 2015 with follow-up through 2016.

The researchers found that the age-adjusted hazard ratio for breast cancer mortality among Black compared with White women was 1.82; neighborhood disadvantage and insurance status together mediated 19 percent of the disparity (mediated hazard ratio, 1.62), and tumor biological characteristics mediated 20 percent (mediated hazard ratio, 1.56). Forty-four percent of the racial disparity (mediated hazard ratio, 1.38) was accounted for in a fully adjusted model including all covariates. For probability of high-risk recurrence score, neighborhood disadvantage mediated 8 percent of the racial difference.

“Racial differences in indicators of aggressive tumor biology that included a genomic biomarker mediated the same proportion of the survival disparity as individual and neighborhood disadvantage,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

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