Insurance drives racial disparities in breast cancer survival

Disparities in health insurance explained more than a third of the excess risk for death among black women with breast cancer compared with white women, according to findings published in Journal of Clinical Oncology.

“Breast cancer mortality was higher in white women than in black women until the early 1980s, when outcomes for black women began to diverge from white women,” Ahmedin Jemal, PhD, vice president of the surveillance and health services research program at American Cancer Society, and colleagues wrote. “Since then, the black-white mortality gap has widened continually; mortality rates for the most recent data year (2014) are 41% higher in black women. This pattern, in part, reflects ethnic/racial differences in the dissemination of mammographic screening and receipt of cancer-directed therapies, among other factors.”

The researchers used the National Cancer Data Base to identify 563,497 white and black women aged 18 to 64 years, all of whom had been diagnosed with stage I to stage III breast cancer between 2004 to 2013. Jemal and colleagues evaluated survival time, OS and excess relative risk for death of all causes. Researchers matched patients by a variety of characteristics, including tumor characteristics, insurance, comorbidity and treatment.

More than three-quarters (78.5%) of patients had hormone receptor-positive disease. Among these, black women had a significantly higher risk for death in a demographics-matched model (HR = 2.05; 95% CI, 1.94-2.17). This discrepancy decreased when patients were sequentially matched for comorbidity (1.93; 95% CI, 1.83-2.04); insurance (1.54; 95% CI, 1.47-1.62); tumor characteristics (HR = 1.3; 95% CI, 1.24-1.36) and treatment (HR = 1.25; 95% CI; 1.19-1.31).

Combined, these factors accounted for more than three-quarters (76.3%) of the excess risk for death in black women. Insurance had the greatest impact, accounting for more than one-third of the difference (37%), followed by tumor characteristics (23.2%) and comorbidities (11.3%). Treatment had the smallest impact (4.8%). Patients with hormone receptor-negative disease demonstrated similar results with “substantially smaller” hazard ratios.

“We found that differences in insurance explained one-third of the total excess risk [for] death in nonelderly black women compared [with] white women diagnosed with early-stage breast cancer, [whereas] differences in tumor characteristics explained approximately one-fifth of the excess risk,” the researchers said in a press release accompanying the study. “Equalization of access to care in nonelderly black women could substantially reduce ethnic/racial disparities in overall mortality of women diagnosed with breast cancer.” – by Andy Polhamus

Disclosures: Jemal reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.