Children with high-risk neuroblastoma from historically marginalized racial and ethnic groups have inferior overall survival (OS) compared to other children, despite uniform planned treatment on pediatric clinical trials. The 5-year OS rate for high-risk neuroblastoma varied by race/ethnicity: 47 percent for Hispanic children; 50 percent for the category of other non-Hispanic children; 61 percent for white non-Hispanic children; and 63 percent for Black non-Hispanic children.
A retrospective cohort study of children with high-risk neuroblastoma included 696 children enrolled on upfront Children's Oncology Group clinical trials from the years 2007 to 2016.
"Our aim was to identify the associations between race, ethnicity, socioeconomic status, and survival outcomes. And...to explore the relationship between race, ethnicity, socioeconomic status, and possible mechanisms for survival, including things like early child discontinuation; delays during induction chemotherapy, which is the first phase of therapy for children with neuroblastoma; and the frequency of relapse," said lead author Puja J. Umaretiya, MD, a Clinical Fellow in Pediatric Hematology/Oncology at Dana-Farber Cancer Institute and Boston Children's Hospital at a press briefing before the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 10005).
Key Findings
When looking at poverty levels, 5-year OS was lower among children with public insurance only (such as Medicaid and the Children's Health Insurance Program) compared to other children (53% vs. 63%). The 5-year OS was also lower for children living in neighborhood level poverty compared to other children (54% vs. 62%). Neighborhood poverty was defined as ZIP codes where 20 percent or more of the population lives below the federal poverty line. Tumor stage and biology did not differ by race/ethnicity or poverty measures in the three Children's Oncology Group trials analyzed.
"Among children with neuroblastoma, Black children are more likely to experience late-occurring relapse and children with public insurance are more likely to relapse and die when treated on immunotherapy clinical trials. The causes of these racial and socioeconomic disparities remain unknown. Clinical trials are the ideal setting in which to study this because the care that children receive on clinical trials is highly standardized," said Umaretiya.
The researchers also looked at poverty by examining where children lived (rural vs. urban areas) and they found no difference in OS. This outcome may be because, regardless of where children lived at diagnosis, all children who participated in these trials had already accessed care at a pediatric cancer center. The results suggest that even when children are treated on the same clinical trials, there are differences in survival by race and ethnicity, she said.
The study group included children who were Black non-Hispanic (16%), Hispanic (11%), other non-Hispanic (4%), and White non-Hispanic (69%). One-third had public insurance only (a proxy for household poverty), 26 percent lived in high poverty ZIP code locations, and 15 percent lived in rural communities.
"We acknowledge that describing disparities is simply not enough. We must strive to identify mechanisms that cause inequitable outcomes. And in this cohort, we begin to do so by looking at things like stopping the trial early, delays in therapy, or increased rates of relapse, none of which seem to explain the survival differences that we see by race and ethnicity. In this cohort, our proxy poverty exposures did not remain significantly associated with survival after adjusting for other factors, such as race, ethnicity, and disease-associated factors," Umaretiya explained.
The next steps will be to look at the interaction of race, ethnicity, and poverty, acknowledging these factors intersect in the United States due to structural racism. "Our data also suggests that, even though relapse occurs at the same frequency across racial and ethnic groups, the rates of death do not," Umaretiya noted. "Our next steps will focus on this post-relapse period, and specifically look at enrollment on early phase trials as a proxy for access to life-extending therapy, as well as the causes of death, looking at whether these children die of disease or toxicity."
Mark L. Fuerst is a contributing writer.