A retrospective study of myeloid leukaemia in children with Down syndrome in Ireland.

BACKGROUND: Acute megakaryoblastic leukaemia (AMKL) is a subtype of myeloid leukaemia and is the most common leukaemia type in children with Down syndrome (DS) under 4 years of age. AMKL is often preceded by a transient neonatal pre-leukaemic syndrome, transient myeloproliferative disorder (TMD). Although TMD often spontaneously resolves, 20-30% of these patients subsequently develop AMKL within the first 4 years of life. AIMS: To perform a retrospective consecutive national audit of all documented cases of childhood TMD and AMKL-DS from 1990 to 2018 at Our Lady's Children's Hospital, Crumlin (OLCHC), Ireland. METHODS: All patients with a diagnosis of AMKL treated consecutively at (OLCHC) between 1990 and 2018 were reviewed. Kaplan-Meier survival curves were constructed. RESULTS: Twenty-seven patients with AMKL-DS were identified. A prior neonatal diagnosis of TMD was described in 10 patients (37%). Nineteen patients (70%) are alive and well, in complete remission, at a median follow-up of 11.4 years. Overall survival (OS) of this cohort has risen from 54% from those treated between the years 1990 and 2004 (n = 13) to 93% for those treated between the years 2005 and 2018 (n = 14). CONCLUSION: High cure rates are observed in AMKL-DS using current polychemotherapy protocols. The finding of a low platelet count at time of diagnosis is in keeping with the knowledge that AMKL-DS is a malignancy of platelet progenitor cells.