Hyperleukocytosis and Access to Minimal Residual Disease Testing Impact Outcomes in Children With Newly Diagnosed Acute Myeloid Leukemia in Thailand.

[BACKGROUND] The survival outcomes among children with acute myeloid leukemia (AML) in low- and middle-income countries are still poor despite adopting modern treatment regimens from developed countries. The study aimed to identify additional potential determinant factors for relapse and death among children with AML in Thailand.

[METHODS] In all, data from 282 children newly diagnosed with AML between 2015 and 2019 across Thailand were retrospectively reviewed. Data, including initial white blood cell numbers, genetic analysis, post-induction minimal residual disease (MRD), hematopoietic stem cell transplantation, and supportive care, were analyzed.

[RESULTS] The probability of 5-year, event-free survival, overall survival, and cumulative incidence of relapse were 40.5%, 42.3%, and 47.4%, respectively. The risk of death was significantly increased among patients stratified as high-risk AML with an adjusted hazard ratio (HR) of 1.8 (95% confidence interval [CI]: 1.1-2.9, p = 0.01). The accessibility to MRD was significantly associated with the risk of death with an adjusted HR of 1.7 (95% CI: 1.1-2.5, p = 0.01). Patients with low-risk AML did carry a significant risk for both death, with an adjusted HR of 1.8 (95% CI: 1.1-3.0, p = 0.02), and relapse, with an adjusted HR of 2.6 (95% CI: 1.5-4.7, p < 0.001) for initial WBC greater than 100,000/mm.

[CONCLUSION] Elevated initial WBC numbers and accessibility to MRD could be considered additional risk factors for unfavorable outcomes in childhood AML.