Clinical and molecular insights into pediatric acute myeloid leukemia in resource-constrained settings.

Abstract

e22004 Background: Pediatric Acute Myeloid Leukemia (AML) is a rare and heterogeneous malignancy with variable outcomes across different regions. This study examined the clinical and molecular profiles of pediatric AML in a Brazilian referral center, emphasizing their correlation with diagnostic and prognostic parameters in a resource-limited setting. Methods: A retrospective analysis was conducted on pediatric AML patients treated between 2014 and 2022. Clinical, demographic, molecular, cytogenetic, and immunophenotypic data were collected and analyzed to identify patterns, correlations, and survival outcomes. Results: A total of 53 pediatric AML patients were analyzed, with a male predominance (56.6%) and the highest incidence among children aged 6–9 years (32.1%). Most patients presented with less than one month of symptoms prior to diagnosis (69.8%) and were referred from public hospitals (83.0%). Common clinical features included febrile neutropenia (66%) and neurological symptoms (24.5%). Karyotyping revealed a predominance of t(15;17)(q22;q21) in 28.3% of cases, complex karyotypes in 20.7%, and t(8;21)(q22;q22.1) in 18.9%. Molecular classification showed a higher prevalence of recurrent genetic abnormalities (58.5%), followed by AML NOS (Not Otherwise Specified) (26.4%) and alterations associated with myelodysplasia (11.3%). Most patients were categorized as intermediate risk (58.4%), with favorable risk observed in 26.4%. PCR identified the PML-RARA fusion in 34% of cases, followed by RUNX1T1-RUNX1 fusion in 18.9%, while 32.1% of patients tested negative. Immunophenotyping demonstrated high expression of CD33 (83%), CD13 (77.3%), and CD117 (75.4%). Subtypes M3 (35.9%), M2 (22.6%), and M7 (9.4%) were the most frequent. Notably, M2 and M3 subtypes were associated with CNS infiltration in 44.4% of cases, while M7 was prevalent in half of the patients who died within the first year of life. Overall survival rates were 60.4%, with 78.9% for M3 and 50% for non-M3 subgroups. Early disease onset ( < 1 year) and complex karyotypes were significantly associated with increased mortality risk. Conclusions: These findings demonstrate higher survival rates compared to underdeveloped countries (20.2–58%) and are comparable to those in developed nations (53.2–75.2%). This study underscores the importance of characterizing the clinical and molecular profiles of pediatric AML in underserved populations. Such insights are critical for improving diagnostic accuracy, refining prognostic tools, and tailoring treatment strategies to bridge survival gaps.