Equity in Precision Medicine: Is It Within Our Reach?
Authors: Katrina Armstrong
Journal: Journal of the National Comprehensive Cancer Network (2017)

Disparities in health and healthcare in the United States are widespread, severe, and unacceptable.Advances in genomics and other precision medicine disciplines over the past several decades have created an important opportunity to reduce health disparities through the development of better diagnostic and predictive tools that reduce the impact of bias and stereotypes on clinical decision-making. 1 However, this promise remains largely unrealized.In fact, lack of inclusion of diverse populations in precision medicine research and lack of access to precision medicine tools among disadvantaged populations risk creating the perfect storm wherein the greatest scientific advances of the past decades are on track to exacerbate rather than alleviate these disparities.Evidence of disparities in the uptake of one form of precision medicine application, genomic tests, has been increasing for more than a decade.One of the first genomic tests to become clinically available was testing for mutations in the BRCA1 and BRCA2 genes, which hit the clinic more than 20 years ago.Perhaps not surprisingly, BRCA1/2 testing is also the first widely available genetic test to demonstrate large and persistent disparities in use. 2 Multiple studies confirm that black or African American women are less likely to undergo BRCA1/2 testing than white women, even when they have the same risk of carrying a mutation, same insurance coverage, and same attitudes about the benefits and risks of testing.Furthermore, this disparity exists among women with a breast cancer diagnosis and those at risk based on family history alone-the 2 key populations who can benefit from BRCA1/2 testing.However, this disparity in the use of genomic tests does not appear to be restricted to germline testing for hereditary cancer risk.More recently, use of somatic testing in breast tumors for gene expression patterns, marketed under the brand name Oncotype DX, has also been found to be lower among minority women.The article elsewhere in this issue, titled "Racial and Ethnic Disparities in Oncotype Dx Test Receipt in a Statewide Population-Based Study," adds further fuel to this fire.In a well-executed population-based study of women with newly diagnosed breast cancer, black and Hispanic women were substantially less likely to have undergone testing, among both those who met testing eligibility criteria based on tumor characteristics and those who did not meet testing eligibility criteria.Again, these disparities are substantial, with eligible non-Hispanic black and Hispanic women having two-thirds the odds of having undergone testing compared with non-Hispanic white women.Despite the number of studies demonstrating disparities in uptake of precision medicine, our understanding of the factors driving those disparities remains limited.Although insurance coverage and patient affordability are critical determinants of access to any health service, large disparities in use of genomic tests have been demonstrated in insured populations.Furthermore, the contribution of lack of insurance may be restricted for somatic testing of tumor samples given that many uninsured patients become eligible for Medicaid coverage at the time of cancer diagnosis.Generosity of insurance coverage varies substantially across payors and plans, and more research is needed to know whether minority women have coverage that is less likely to include genomic tests or whether they face more administrative barriers to obtaining appropriate counseling or coverage for those tests.Just as differences in insurance coverage do not appear to be the primary driver of these disparities to date, it has also proven difficult to explain disparities in genomic tests by differences in other patient characteristics.Test eligibility can vary across race