Common Genetic Mutation
To better understand what contributed to the better outcomes seen in younger African American veterans compared to European Americans, Fillmore and his colleagues homed in on a common genetic mutation associated with worse prognosis. The mutation, deletion of TP53/17p (del17p), occurs in about 10% of multiple myeloma patients overall.
Of the 2,677 veterans in the study, 7.4% had the mutation, but the frequency varied substantially between the two groups. Only 4.73% of AA veterans had it, while 8.82% of EA veterans did. The difference was particularly stark in younger veterans, 3.73% vs. 8.30% for AA and EA veterans under age 65, respectively.
The reduced presence of the adverse mutation in younger veterans had a disproportionate effect on the total AA population as half of AA veterans with multiple myeloma in the study were under the age of 65, whereas only one-third of EA veterans were in the younger group.
In veterans with the deletion, the researchers found no difference in survival between AA and EA veterans or between younger and older patients. Overall, veterans with the deletion had shortened survival compared to those who did not have it, 2.26 years vs. 4.27 years.
“It didn’t surprise us that del17p is associated with worse survival across the board, young and old and across races,” Fillmore said. “What we saw is, among veterans who have del17p, there is not much survival difference, but among those who do not, there is.”
Younger AA veterans without the mutation lived substantially longer than EA veterans, 7.75 years vs. 4.87 years. The researchers found no significant difference in survival among older veterans without the mutation.
The mutation “is less common in African Americans and it is associated with worse survival, however, that only partially accounts for the difference in survival we found,” Fillmore noted.
The researchers looked at the therapies used to see if they had an effect on the difference in survival and found that AA veterans had superior survival across all three regimens evaluated. “There were still differences, even when receiving the same treatment,” Fillmore observed. “It’s topic for future research for sure.”
He did have some ideas, however. “One thing is that transplants are given more often to people under 65,” Fillmore suggested. “The aggressiveness of therapy is definitely higher in younger patients.”
African Americans also had “better response to bortezomib- and lenalidomide-based doublet and triplet induction regimens, suggesting possible differences in disease biology other than del17p that may contribute to a more indolent course and increased sensitivity to therapy,” the study authors wrote.
“The big finding is when access is equalized, African Americans do not have worse outcomes than white patients. In fact, they have better outcomes, which highlights the need to equalize care regardless of healthcare system,” Fillmore concluded. “Lack of access drives disparities.”
- Munjuluri A, Fillmore N, Cirstea D, et al. With Equal Access, African Americans with Non-del17p Multiple Myeloma Have Superior Overall Survival, but Del17p Still Carries Poor Prognosis across Race: A VA Study. 2019 ASH Annual Meeting. 9 Dec 2019. Abstract 4388.
- Waxman AJ, Mink PJ, Devesa SS, et al. Racial disparities in incidence and outcome in multiple myeloma: a population-based study. Blood. 2010;116(25):5501–5506. doi:10.1182/blood-2010-07-298760
- Study finds racial disparities in treatment of multiple myeloma patients. ASH press release. 17 Oct 2019.
- American Cancer Society. Cancer Facts & Figures for African Americans 2019-2021. Atlanta: American Cancer Society, 2019.