Minimal residual disease in childhood B Lymphoblastic Leukemia and its correlation with other risk factors

Area of Science:

• Pediatric Oncology
• Hematology
• Molecular Diagnostics

Background:

• Minimal residual disease (MRD) is a critical prognostic indicator in pediatric B-lymphoblastic leukemia (B-ALL).
• Understanding MRD kinetics and its association with clinical factors is crucial for risk stratification and treatment optimization.

Purpose of the Study:

• To determine the frequency of MRD positivity after induction and consolidation therapy in pediatric B-ALL patients.
• To investigate the association between post-induction and post-consolidation MRD status and various clinical risk factors.

Main Methods:

• A retrospective, cross-sectional study of pediatric B-ALL patients (ages 1-17) treated between May 2015 and January 2018.
• MRD testing was performed on bone marrow aspirates using four-color flow cytometry with a 0.01% cutoff on day 35 post-induction and post-consolidation.
• Clinical data including demographics, total leukocyte count (TLC), central nervous system (CNS) status, and cytogenetics (BCR-ABL, MLL, TEL-AML1) were analyzed.

Main Results:

• Out of 362 patients, 37% were MRD positive post-induction, with no significant association to most clinical factors except MLL (p=0.05).
• Post-consolidation, 44% of patients were MRD positive.
• Age, National Cancer Institute (NCI) risk groups, and CNS status showed a statistically significant association with post-consolidation MRD (p < 0.05).

Conclusions:

• High rates of MRD positivity are observed in pediatric B-ALL patients post-induction and post-consolidation.
• Post-induction MRD status showed limited association with clinical risk factors.
• Post-consolidation MRD positivity is significantly associated with adverse prognostic factors including age, NCI risk group, and CNS status, highlighting its importance in late-stage risk assessment.