Minimal Residual Disease-guided Risk Restratification and Therapy Improves the Survival of Childhood Acute Lymphoblastic Leukemia: Experience From a Tertiary Children's Hospital in China.

The minimal residual disease (MRD) has been shown to be very important to evaluate the prognostic significance in childhood acute lymphoblastic leukemia (ALL), but the impact under the current treatment protocol in China has not been fully elucidated. The aim of this study was to investigate the efficacy of MRD-guided risk restratification of ALL. A total of 676 children with ALL were enrolled. In the predictive study group, 476 patients were enrolled with 5-year cumulative incidence of relapse rates of the low-risk (LR), intermediate-risk (IR), and high-risk groups being 11.0%±2.3%, 12.6%±3.3%, and 32.7%±4.9%, respectively. In the intervention study group, 19/200 patients enrolled were reclassified into risk groups according to the MRD levels. The 3-year event-free survival and overall survival were 85.2%±2.9% and 90.6%±2.1%, respectively, which were higher than those of the predictive study group (79.1%±1.9% and 84.7%±1.7%, respectively; P<0.05). The 3-year cumulative incidence of relapse in the LR and IR groups of the intervention study group were 4.2%±3.1% and 6.4%±3.1%, respectively, which were significantly lower than those in the predictive study group (7.2%±1.8% and 11.8%±3.2%, respectively; P<0.05). We conclude that the risk of relapse in the LR and IR groups can be significantly reduced after MRD-guided risk restratification.