Survival outcomes of myeloid leukemia associated with Down syndrome and de novo acute myeloid leukemia in children: Experience from a single tertiary center in Thailand.

Few studies have reported the survival outcomes of myeloid leukemia associated with Down syndrome (DS) in resource-limited countries. This study aimed to compare characteristics and survival outcomes of children with acute myeloid leukemia (AML) between those with and without DS in Thailand. The medical records of AML patients aged 0-15 years treated in a major tertiary center in Southern Thailand between October 1978 and December 2019 were reviewed retrospectively. The overall (OS) and event-free survivals (EFS) rates were calculated using the Kaplan-Meier method. A total of 362 AML patients were included, of which 41 (11.3%) had DS. The mean age at diagnosis of the DS patients was 2.5 ± 1.9 years and most of them (90.2%) were under the age of five. The DS patients had lower initial white blood cell counts and peripheral blasts compared to the non-DS patients. The AML-M7 subtype was more common in the DS than in the non-DS patients (80.5% vs. 9.1%, p  < 0.01, respectively). The 5-year OS and EFS rates of the DS patients were lower compared to the non-DS patients (12.9% vs. 20.5%, p  = 0.05 and 13.7% vs. 18.4%, p  = 0.03, respectively). DS patients had a significantly higher rate of early and treatment-related deaths compared to non-DS patients (30.3% vs. 13.5%, p  < 0.01 and 39.4% vs. 19.5%, p  = 0.02, respectively). Over the study period, there were a decrease in early death rate and an increase in survival rates of DS patients, which suggests that chemotherapy regimens and supportive care have improved over time.