A new study, published by researchers at the University of Toronto in the Jan. 13, 2015, issue of JAMA, argues that much of the racial and ethnic variation in the early detection of breast cancer and differences in survival seven years after diagnosis can be accounted for by intrinsic biological differences, such as lymph-node metastasis, distant metastasis, and triple-negative disease.
The study looked at data from almost 400,000 women in the United States who were diagnosed with breast cancer between 2004 and 2011. It found significant disparities related to race or ethnicity.
Black women, for example, were less likely than non-Hispanic white women to be diagnosed with stage 1 breast cancer. They tended to have more aggressive tumors when diagnosed and to have more triple-negative breast cancers—tumors that lack the markers of estrogen receptor, progesterone receptor, and Her2 overexpression and thus have not benefited from the same pharmacologic breakthroughs as other breast cancer subtypes. They were also more likely to die from their breast cancer in the next seven years. The researchers attributed the disparities primarily to biological characteristics of their breast cancers.
An editorial about the study, however, discussed the important role of disparities in health care delivery as well. University of Chicago cancer specialists Olufunmilayo Olopade, MD, and Bobby Daly, MD, MBA, from the Department of Medicine and the Center for Global Health, argue that biology cannot be viewed as the only factor in the survival gap.
“There remain variations by race and ethnicity in the quality of breast cancer screening,” they wrote. “Delays in treatment, misuse of treatment…and underuse of treatment,” all play a role. Black women suffer from “failures in the delivery and development of novel interventions,” they added. “This fertile research area,” they said, “is limited by gaps in referrals of minority patients to cancer risk clinics.” Nor do black women have comparable access to genetic evaluation or clinical trials.
“We need to eliminate financial and administrative barriers to minority enrollment in clinical trials to improve our understanding of these biologic differences and improve our treatment options,” Daly said. “We also need to address the gap in referrals to cancer risk clinics. More data on African American genetic variants will create more robust risk-assessment models.”
“Closing the survival gap,” they conclude, “will only occur once health care leaders initiate system changes that improve access to high-quality care along with a more comprehensive study of breast cancer biology through inclusion of a substantial number of minority patients in ‘omics’ research and clinical trials.”