Colorectal cancer patients of African ancestry are less likely to have tumors that respond well to two important classes of newer treatments: immunotherapy and targeted therapy, according to an analysis of genetic data from 4,441 people treated for colorectal cancer at Memorial Sloan Kettering Cancer Center in New York.
These treatments work better against tumors that have certain genetic mutations — or have a larger number of mutations overall. The research found that a smaller fraction of the Black patients whose tumors were sequenced at MSK had molecular profiles that could be targeted by these therapies compared with people of other ancestries.
The study also found that the presence of some genetic mutations that can typically be used to group patients into predicted outcomes was not helpful in predicting outcomes in patients of African ancestry. And people of African ancestry had a significantly shorter median survival time after diagnosis — about two-thirds as long — than patients of all other ancestry groups.
“Our findings suggest that the type of molecular profiles observed in the tumors of patients with African ancestry could reduce the number of options that these patients have for treatment,” said Henry Walch, who presented the findings at a 2023 scientific meeting. “They also underscore the urgent need to include racially diverse populations in cancer research and drug development studies.”
- See “Why Is Colorectal Cancer in African Americans Hard To Treat? One Reason Is Genetics” by Jim Stallard on the Memorial Sloan Kettering Cancer Center website (April 17, 2023)
- See the abstract of the scientific presentation “Clinical genomic profiling identifies lower frequency of therapeutically actionable alterations and lower prognostic value of APC inactivation in colorectal cancer patients of African ancestry” by Henry Walch et al.
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