Treatment results in children with myeloid leukemia of Down syndrome in Saudi Arabia: A multicenter SAPHOS leukemia group study.

Despite the high incidence of Down syndrome (DS) in Arab countires, the incidence and outcomes of myeloid leukemia of DS (ML-DS) have not been studied. We evaluated 206 pediatric acute myeloid leukemia (AML) patients diagnosed between 2005 and 2012 and identified 31 (15%) ML-DS. The incidence of ML-DS was 48 per 100,000 compared to 0.6 per 100,000 for AML in non-DS children. Thus, patients with DS had 80-fold increased risk of ML-DS compared to AML in non-DS children. The median age at diagnosis was 1.8 years, male/female ratio was 1.2, majority (84%) of patients had FAB-M7 subtype, and the cytogenetic abnormalities were normal karyotype (constitutional trisomy 21) in 48%, additional trisomy in 23%, and other aberrations in 29%. Complete remission, cumulative incidences of relapse (CIR), toxic-death, and 5-year event-free survival (EFS) rates were 96.8%, 19.4%, 13.1%, and 67.7±8.4%; respectively. In the present study, multivariate analysis revealed favorable outcome (5-year EFS 86.7±8.8%) for patients with normal karyotype. The incidence and clinical characteristics of ML-DS in Saudi patients were comparable to other reports. However, there is a need to optimize risk stratification and treatment intensity to reduce CIR and toxic death rates to further improve outcomes of patients with ML-DS.

Clinical characteristics and outcome of childhood de novo acute myeloid leukemia in Saudi Arabia: A multicenter SAPHOS leukemia group study.

Geographic variation and ethnicity have been implicated to influence the outcome of pediatric acute myeloid leukemia (AML). Furthermore, survival outcomes from developing countries are reported to be inferior to developed nations. We hypothesized that risk- and response-based outcome in high-income resource-rich developing countries would be comparable to developed nations as access to care and supportive measures would be similar. A total of 193 children diagnosed with de novo AML between January 2005 and December 2012 were identified, of those 175 were evaluable for outcome. Patients were stratified into low-risk (LR), intermediate-risk (IR), or high-risk (HR) groups. The complete remission (CR), early death, and induction failure rates were: 85.7%, 2.3%, and 12%; respectively. The 5-year cumulative incidences of relapse (CIR) and non-relapse mortality (NRM) were 43.1% and 9.8% respectively; overall survival (OS) was 58.8±4% and event-free survival (EFS) 40.9±4.1%. The 5-year OS for LR, IR, and HR groups were 72.0±6.9%, 59.8±6.2%, and 45.1±7.4%; respectively (p=0.003); and EFS 50.5±8.0%, 46.3±6.4%, and 23.3±6.4%; respectively (p=0.001). This study demonstrated comparable outcomes to those reported from developed countries. This suggests that utilization of risk- and response-based protocols in developing countries can overcome ethnic and geographic variation, if access to care and supportive measures were similar.