Outcomes of down syndrome-related myeloid leukemia in Turkiye: a multicenter retrospective observational cohort study by the Turkish Pediatric Hematology Association.

Children with Down syndrome (DS) have a 150-times increased risk of myeloid leukemia (ML). In DS patients, in addition to DS-ML, common acute myeloid leukemia (AML) subtypes (standard-AML), observed in patients without DS, may also be seen. We evaluated ML types developing among DS cases, along with clinical features, survival, relapse, and mortality rates. The study included DS children aged 6 months to 18 years with newly diagnosed ML. Patients were classified retrospectively into two groups according to WHO guidelines and BFM-AML protocol recommendations as DS-ML and standard AML-DS. Among 53 DS patients, 71.7% (n = 38) had DS-ML and 28.3% (n = 15) had standard AML-DS. The mean age in the DS-ML group was significantly lower than the standard AML-DS group (23 ± 9 vs. 48 ± 51 months, p = 0.033). The 5-year overall survival (OS) and event-free survival (EFS) in the DS-ML group were 84.1%±6.0% and 81.3%±6.4%, respectively. For the standard AML, OS and EFS were 53.3%±12.9% and 45.7%±13.1%, respectively. The DS-ML group had significantly higher OS and EFS than the standard AML-DS group (p = 0.039 and p = 0.025, respectively). In our study, DS-ML and standard AML-DS were evaluated separately, which significantly contributes to the literature on the clinical and laboratory features of both groups, given the limited data on these topics. In the DS-ML group, complete remission, OS, and EFS were significantly higher than in the standard AML-DS. Differentiating DS-ML from standard AML-DS will ensure that patients with these biologically distinct diseases receive treatment of appropriate intensity and increase survival by reducing early mortality and relapse risk.