Racial Disparities Seen in Survival Among Pediatric Patients With Acute Lymphoblastic Leukemia

Sumit Gupta, MD, of The Hospital for Sick Children in Toronto, Canada, told attendees at the 63rd Annual American Society of Hematology Meeting that biological or genetic factors accounted for some of the gap in survival rates, but not all.

White patients with acute lymphoblastic leukemia (ALL) had a 5-year event-free survival (EFS) that was significantly higher than that of Hispanic and Black patients in a study of nearly 25,000 youth by the Children’s Oncology Group (COG). The findings were presented Saturday at the 63rd Annual American Society of Hematology (ASH) Meeting and Exposition, taking place in Atlanta and online.

Of interest to policymakers is that children in the United States with Medicaid coverage have a lower survival rate than children who are not in Medicaid. But more surprising was the fact that children in the study who lived outside the United States — in countries like Canada, Australia or New Zealand — had a 29% lower risk than white children in the United States.

Sumit Gupta, MD, of The Hospital for Sick Children in Toronto, Canada, said biological or genetic factors accounted for some of the gap in survival rates, but not all. “Our study shows that race and ethnicity-based inequalities persist and are significant,” Gupta said. “All groups are generally doing well, but some are doing significantly better than others.”

For the study, researchers examined a cohort of 24,979 children, adolescents and young adults with ALL. Patients who were non-Hispanic white accounted for 13,872 (65.6%) of the group, followed by 4354 (20.6%) who were Hispanic and 1,517 who were non-Hispanic black.

Just over a quarter was covered by US Medicaid (27.8%), or 6,944 patients.

The 5-year EFS was 87.4% (±0.3%) among non-Hispanic Caucasian patients vs 82.8% (±0.6%) for Hispanic patients (HR 1.37, 95% CI: 1, 25-1.49;P < 0.0001); and 81.9% (±1.2%) for non-Hispanic Black patients (HR 1.45, 95% CI: 1.28-1.56, P < .0001). Researchers reported that outcomes for non-Hispanic Asian patients were similar to white patients.

Insurance status. US patients on Medicaid had worse outcomes compared to other US patients. Medicaid was associated with a 5-year EFS of 83.2% vs 86.3% for US patients not receiving Medicaid (HR 1.21, 95% CI: 1.12-1.30; P < .0001). Non-US patients in this cohort had even better outcomes in 5-year EFS, 89.0% (HR 0.78, 95% CI: 0.71–0.88; P < .0001). However, this group was small compared to the total group of 3151 patients.

Explanations for the findings. Gupta said that after identifying these inequalities, the researchers tried to figure out how they could be explained by imbalances in other predictors. “It’s not surprising, for example, that socioeconomic status varied by racial ethnicity — 50% of Hispanic patients were on Medicaid versus only less than 20% of non-Hispanic White patients,” he said. “Similarly, disease predictors also vary by race and ethnicity.”

Researchers found that the worse outcome of EFS in Hispanic patients was significantly reduced by the addition of disease predictors, lowering HR from 1.37 to 1.17; this was further mitigated by including socioeconomic status or SES (HR 1.11).

In contrast, researchers wrote, “the increased risk in non-Hispanic black children was minimally reduced by both the addition of disease predictors and the subsequent addition of SES (HR 1.45 to 1.38 to 1.32).

Notably, this process produced patterns in which “differences in overall survival were greater than those observed in event-free survival,” Gupta said.

During the session, the participants brought up possible confounders, such as increased obesity rates or pulmonary arterial hypertension in Hispanic patients. Each of these can tell part of the story, and they are all worth exploring.

“It’s possible there’s residual confusion here from disease predictors that we haven’t fully accounted for,” he said. “However, it seems unlikely that this explains the entire medical experience that we’re seeing, so we’re left with somewhat inconvenient mechanisms to talk about, like differential access to care, differential quality of care.

“And when we use the sadly politically charged ‘systemic racism’ or some other term, the possibility that even pediatric oncology health care systems are systematically delivering difficult care to patients from different racial groups.”

B-ALL vs T-ALL. One key difference revealed by this process is the fact that disparities are largely driven by ALL B-cell lineages, rather than T-cell lineage, Gupta noted, presenting a slide showing the differences in the data. to see.

During the press conference, Gupta noted, “The treatment is quite similar and is provided by the same centers.” Typically, a patient will receive 8 to 10 months of intensive therapy followed by 18 to 24 months of lower intensity or maintenance treatment. In this second phase, researchers may need to look for clues to explain the survival gaps, he said.

“There’s not as much control and not as much control as oncologists will,” he said. “Maybe if we deliver different care to these ethnic and racial groups and maintenance, that could explain some of those findings.”

Reference

Gupta S, Teachey DT, Devidas M, et al. Racial, ethnic, and socioeconomic factors result in differences in outcome in children with acute lymphoblastic leukemia not completely attenuated by disease predictors: a study of the pediatric oncology group. Presented at: The American Society of Oncology’s 63rd Annual Meeting and Exposition; Atlanta, GA; December 11, 2021. Summary 211. https://ash.confex.com/ash/2021/webprogram/Paper147386.html

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