# A multicenter observational cohort study in survivors of Down Syndrome-associated acute leukemia (ALTE22C1): a report from the Children’s Oncology Group

## TL;DR

This study compares health and cognitive outcomes in children with Down syndrome who survived leukemia to those with Down syndrome but no cancer history.

## Contribution

It is a first-of-its-kind multicenter study examining late effects of leukemia treatment in Down syndrome survivors.

## Key findings

- The study will identify the prevalence of chronic health conditions in Down syndrome leukemia survivors.
- It will compare neurocognitive outcomes between survivors and non-cancer Down syndrome individuals.
- Biological samples will help link molecular features to health outcomes.

## Abstract

Down syndrome (DS) is a common genetic disorder resulting from an extra copy of genetic material from all or part of chromosome 21. Individuals with DS have a higher burden of co-occurring structural birth defects, neurocognitive delay, and chronic health conditions when compared to those without DS, as well as a 10 to 20-fold excess risk for acute leukemia (AL). Few studies have reported the late effects of cancer treatment in DS-AL survivors, and even fewer have compared outcomes to children with DS and no cancer history. The Children’s Oncology Group study ALTE22C1 was developed to address this knowledge gap.

This study leverages both registry and site-based DS-AL survivor recruitment and a prospective/retrospective cohort design to compare chronic health conditions and neurocognitive outcomes experienced by DS-AL survivors to age and sex-matched individuals enrolled to a DS cohort for which cancer is exclusionary. Survivors 6–39 years old, ≥ 3 years from end of AL treatment, and in remission are eligible. Participants complete a medical conditions survey and neuropsychological battery by parent proxy and may also participate in an in-person physical and neurocognitive assessment. Biological samples are collected to evaluate molecular features associated with outcomes.

This cooperative group study will identify the prevalence and severity of medical and neurocognitive outcomes in DS-AL survivors compared with non-DS AL and DS controls without cancer history. Results are anticipated to inform clinical practice guidelines for DS-AL survivors and improve survivor outcomes through mitigation of outcome disparities in this vulnerable population.

Children’s Oncology Group study ALTE22C1 is registered under the ClinicalTrials.gov identifier NCT05702645.