Study Examines Disparities in Relapse Among Pediatric Patients With ALL

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According to a large multiethnic study presented by Sok et al at the American Association for Cancer Research (AACR) Annual Meeting 2022, Latinx children with acute lymphoblastic leukemia (ALL) and measurable residual disease (MRD)-negative status were more likely to relapse compared with non-Latinx White children with MRD-negative ALL (Abstract 3633). Socioeconomic status and neighborhoods where people lived were not associated with ALL relapse.

Study Background

ALL is the most common cause of childhood cancer, and survival in children with the disease is currently around 90%. However, about 15% of children with ALL will relapse. Outcomes are much worse after relapse, with about 35% of children surviving after disease recurrence. ALL remains a leading cause of death by disease in children, and disparities in outcomes related to racial or ethnic factors have been reported.

“Relapse is one of the strongest predictors of mortality, and the presence of minimal residual disease at the end of induction is one of the strongest predictors of relapse,” explained senior author Philip J. Lupo, PhD, MPH, Professor of Pediatrics at Baylor College of Medicine/Texas Children’s Hospital, Houston. Dr. Lupo presented the findings at a press conference held during the AACR meeting. “Previous studies have suggested that the neighborhood where a person lives may be as predictive of outcomes as one’s genome. The saying goes, ‘Your zip code is as important as your genetic code.’”

Dr. Lupo and his co-researchers wanted to understand the disconnect observed in their patients between MRD-negative status and relapse. “There have been few assessments of ALL relapse among large multiethnic populations, and we wanted to consider neighborhood disparities and other factors that could contribute to relapse in a large, predominantly [Latinx], pediatric cohort,” he told listeners.

The study was based on data from the Reducing Ethnic Disparities in Acute Leukemia (REDIAL) Consortium, which includes patients diagnosed with ALL at seven major pediatric centers in the southwestern United States. The investigators analyzed data on 1,662 children diagnosed with ALL between 2004 and 2018. Median age at diagnosis was 5 years. About 60% were Latinx, and 60% were male.

Key Findings

The relapse rate for these children was 14%, and 63% of relapses occurred in children who were MRD-negative. Latinxs and non-Latinx Blacks were significantly more likely to experience relapse compared to non-Latinx Whites (P = .0018).

Among 382 MRD-positive patients (23.5% of the total population), the relapse rate was 19.1% (n = 73), compared to 11% of MRD-negative patients. Among MRD-positive patients, the relapse rates between Latinxs and non-Latinx Whites were similar. However, Latinxs who were MRD-negative were 65% more likely to have a relapse than non-Latinx whites.

“This suggests that MRD status may not be as strong a prognostic factor in predicting the risk of relapse in [Latinx] children with ALL compared to non-[Latinx] whites,” Dr. Lupo said.

Looking at other factors associated with relapse, the neighborhood you lived in did not seem to affect relapse, which was a surprise, he noted.

“These findings that [Latinxs] are more likely to relapse if they were MRD-negative suggest that these patients should be considered at higher risk for relapse and treated more aggressively,” Dr. Lupo suggested. “The study suggests ‘triggers’ for relapse, and molecular studies would help us stratify these individuals for treatment.”

Disclosure: The study authors reported no conflicts of interest.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.