Minimal residual disease in B-precursor acute lymphoblastic leukemia: Clinical significance on post-induction treatment

Abstract

Minimal residual disease (MRD) assessment in patients with acute lymphoblastic leukemia (ALL) became an integral part of total evaluation of chemotherapy efficacy. No doubt, that it is necessary to evaluate MRD at remission induction and before allogenic stem cell transplantation, but MRD prognostic role at post-induction treatment is on-study.Aim. To evaluate a prognostic significance of MRD at post-induction treatment in pediatric patients with ALL.Materials and methods. From October 2010 to September 2022, there were 142 pediatric patients with primary diagnosed B-precursor ALL enrolled the study. All the patients were treated by ALL–IC BFM 2009 protocol.Results. 6-year overall survival (OS) for patients with MRD-positive status at post-induction treatment (78th day of therapy) was 90.8 ± 4.0 %, with MRD-negative – 91,1 ± 3.9 % (р = 0,8). Relapse-free survival (RFS) for MRD-positive – 67.4 ± 11.6 %, MRD-negative – 88.9 ± 4.3 % (р = 0,03). Event-free survival for MRD-positive – 67.4 ± 11.6 %, MRD-negative – 87,5 ± 4.5 % (р = 0,06).Conclusion. MRD level at induction remission treatment is an important risk-stratified factor in pediatric patients with ALL, but prognostic significance of MRD at post-induction therapy is under investigation. Presented our data showed increased relapse incidence on 21.5 % in patients with MRDpositive status at 78th day of therapy. OS was the same and not depended on post-induction MRD-level.