ALL-124 Outcome of Acute Leukemia in Down Syndrome: A Retrospective Experience of Ain Shams Pediatric Oncology Over a Decade.

INTRODUCTION: Children with Down syndrome are at an elevated risk of acute leukemia, namely myeloid leukemia (ML-DS) and acute lymphoblastic leukemia (DS-ALL), though the higher risk of developing leukemia remains largely unclear. This malignancy is frequently preceded by transient abnormal myelopoiesis, which is self-limited, as recently published in our center. Acute megakaryoblastic leukemia (M7) is a rare subtype of pediatric acute myeloid leukemia with better outcomes in patients with Down syndrome.

PATIENTS AND METHODS: Ain Shams genetic center, established in 1964, serves more than 200 new Down syndrome patients annually. The pediatric oncology center, started in 1974, serves nearly 100 new acute leukemia patients yearly. The main outcome was to evaluate the prognostic significance of cytogenetic abnormalities and minimal residual disease status as determined by flow cytometer after induction. We retrospectively analyzed the data of 30 patients with a diagnosis of ML-DS and ALL-DS at Ain Shams over the last decade (2010-2020).

RESULTS: Sixty percent of the patients were female, and ages ranged from 9 to 92 months. Diagnosis was either ALL (n=7) or AML (n=23), including M7 (n=5). Event-free survival at 2 years was 70%, whereas 10% died during induction; the cumulative incidence of relapse at 2 years (n=5) was 15%, and one patient was excluded from the survival analysis. Of the 30 patients, half had cytogenetic abnormalities; none of these had an effect on the outcome. In addition, one-third of patients had minimal residual disease <0.1% after induction, but the difference did not reach statistical significance.

CONCLUSIONS: Acute leukemia, whether acute megakaryoblastic leukemia or not, had an improving response over the last decade in children with Down syndrome compared with those without, with no clearly defined prognostic factors.