Abstract

Purpose
Outcomes of children and adolescents with acute lymphoblastic leukemia (ALL) treated using an institutional risk-adapted strategy were assessed, and survival was compared among risk groups.
Materials and Methods
This retrospective study included patients newly diagnosed with ALL during 2006–2020. Patients were stratified as standard-risk (SR), high-risk (HR), or very-high-risk (VHR). The SR group received a POG 9605-based protocol in 2006–2011 and a modified regimen with an additional delayed intensification phase in 2012–2020. The HR group received the ALL 0601 regimen, and the VHR group received institutional hematopoietic stem cell transplantation-oriented treatment.
Results
Ninety-two patients were included (SR, 34; HR, 45; and VHR, 13). The 10-year overall survival (OS) and event-free survival (EFS) were 85.2% and 70.9%, with cumulative incidences of relapse and treatment-related mortality of 22.6% and 3.3%, respectively. The 10-year OS was 92.8%, 88.7%, and 60.9% in the SR, HR, and VHR groups, and the corresponding 10-year EFS was 78.5%, 77.2%, and 34.2%, respectively. In SR, 10-year OS/EFS were 85.1%/71.4% in 2006–2011 and 100%/84.4% in 2012–2020. In the HR group, rapid early responders exhibited significantly better outcomes than did slow early responders, with 10-year OS of 97.0% vs. 63.6% (p = 0.001) and 10-year EFS of 87.9% vs. 43.6% (p < 0.001). Most relapses occurred during therapy or within 3 years of treatment completion.
Conclusion
VHR patients and HR patients with slow early response demonstrated the poorest outcomes. This supports refining risk-directed treatment strategies, including prospective evaluation of intensified and novel therapeutic approaches.

• Keywords: Acute lymphoblastic leukemia, Pediatrics, Risk factors, Prognosis