Research Spotlight: Disparities According to Genetic Ancestry in the Use of Precision Oncology Assays

Mata, D., et al. N Engl J Med. 2023; 388:281-283, DOI: 10.1056/NEJMc2213457

Modern oncology has moved away from a one-size-fits-all approach to cancer care and has been replaced by a more personalized approach to treatment. This new approach relies on understanding the molecular makeup of each patient’s specific disease through comprehensive genomic testing.

However, personalized cancer care has not always been made equitably available to all patient populations. Evidence regarding disparities in access to comprehensive genomic profiling is lacking, and there is still work to be done in bringing this testing to all patients who need it.

In our study, recently published in the New England Journal of Medicine, we examined the use of comprehensive genomic profiling, which helps doctors to find specific cancer drivers in their patient that may be therapeutic targets. The study examined genetic ancestry of patients from our large cancer genomics database.

Using the five ancestral superpopulations in the 1,000 Genomes Project as our categories, we looked at 620,500 samples from all 50 states to see how use of both our tissue- and blood-based tests has evolved over a 9.5-year period.

The study found that the use of genomic profiling among traditionally underserved racial and ethnic groups, as assessed according to genetic ancestry, has increased over the past decade. Relative to the total number of patients tested, which grew over time, the percentage of patients with African ancestry and admixed American ancestry both increased, whereas the percentage of patients with European ancestry decreased.

In particular, the percentage of patients who underwent genomic testing who had predominantly African ancestry increased by half a percentage point each year, reaching 12.4% by September 2022, a percentage that is similar to the 11.6% of adults 55 to 74 years of age who identified as Black or African American in 2021 U.S. Census data. This is an indication that our dataset is reflective of real-world data, and that our database is increasingly representative of the population.

Our findings underscore progress in expanding access to cancer genomic testing to historically marginalized groups and inspire our continued efforts to broaden the accessibility of personalized cancer care.

View the full publication on NEJM.org