Prognostic significance of end-of-induction measurable residual disease in childhood acute lymphoblastic leukemia: a retrospective cohort study from Eastern India

Measurable residual disease (MRD) has emerged as the most important prognostic biomarker in pediatric acute lymphoblastic leukemia (ALL). However, robust outcome data from resource-constrained settings in India remain limited. The aim of this study was to evaluate the prognostic significance of end-of-induction MRD (EOI-MRD) in childhood ALL and its association with baseline clinicobiologic characteristics and survival outcomes. This retrospective single-center cohort study included children with ALL treated between January 2016 and December 2025 using a modified ALL BFM-IC 2002 protocol. EOI-MRD was assessed by multiparameter flow cytometry (sensitivity 0.01%). Survival analysis was performed using the Kaplan–Meier method, whereas logistic regression analysis identified predictors of MRD positivity. A total of 262 children with ALL were included, of whom 247 underwent EOI-MRD assessment; 13 died during induction chemotherapy and 2 had induction failure. MRD positivity was detected in 27 patients (10.9%) and was significantly associated with older age (> 10 years; p = 0.038), T-cell immunophenotype ( p = 0.005), NCI high-risk disease ( p = 0.038), and BFM high-risk stratification ( p = 0.016). T-cell immunophenotype demonstrated the strongest association with EOI-MRD positivity (OR 3.73; 95% CI 1.57–8.87; p = 0.003). At a median follow-up of 36 months, estimated 5-year EFS and OS were 71.5% and 78.7%, respectively. MRD-positive patients had inferior 5-year EFS (52.6% vs. 73.9%; p = 0.012) and OS (63.1% vs. 81.6%; p = 0.020), with higher relapse rates (37.0% vs. 15.9%). Our findings are consistent with previously published studies and further confirm the prognostic importance of end-of-induction MRD in children with ALL treated in a low- and middle-income country. MRD-guided risk stratification should be routinely incorporated into pediatric ALL management.