[Clinical significance of minimal residual disease in patients with Ph-negative precursor B-acute lymphoblastic leukemia].

To explore the predictive value of minimal residual disease (MRD) level in Ph-negative precursor B-acute lymphoblastic leukemia (ALL) patients. 193 Ph-negative B-ALL patients from Sep 2010 to Nov 2017 were involved in the study. The patients' MRD evaluation which can be performed by multiparametric flow cytometry (MFC) after 1 month, 3-month, 6-month treatment. Relapse free survival (RFS) and overall survival (OS) were compared in patients with different MRD level. The median follow-up was 22 months. All patients was evaluated at 497 MRD level. Patients who reach the good MRD level at 1 month (<0.1% or ≥0.1%), 3-month (negative or positive), 6-month (negative or positive) had a significantly higher probability of estimated RFS (74.5% 29.9%; 75.6% 29.7%; 74.6% 11.6%) and of estimated OS (67.5% 30.3%; 71.6% 27.8%; 74.0% 15.7%). Patients who reach the MRD negative at all 3 times had a significantly higher probability of estimated RFS (80.5% 30.5%) and better estimated OS (77.1% 29.4%) compared to patients with at least MRD failure in one time (<0.001). Multivariable analysis showed MRD level at 3-month was an independent prognostic factor for DFS and OS. MRD is an important prognosis factor for Ph-negative B- ALL patients.