Minimal residual disease (MRD) is an important predictor of relapse in acute lymphoblastic leukemia (ALL), but its relationship to other prognostic variables has not been fully assessed.
Studies show that the presence of residual leukemia is significantly correlated with the risk of early relapse.
The Children's Oncology Group studied the prognostic impact of MRD measured by flow cytometry in the peripheral blood at day 8, and in end-induction (day 29) and end-consolidation marrows in 2143 children with precursor B-cell ALL (B-ALL). The presence of MRD in day-8 blood and day-29 marrow MRD was associated with shorter event-free survival (EFS) in all risk groups; even patients with 0.01% to 0.1% day-29 MRD had poor outcome compared with patients negative for MRD patients (59% ± 5% vs 88% ± 1% 5-year EFS).
