Early detection of MRD in peripheral blood after induction chemotherapy of newly diagnosed patients with AML and its correlation with curative effects

Abstract

The purpose of this study was to detect the minimal residual disease (MRD) in peripheral blood of newly diagnosed patients with acute myeloid leukemia (AML) on day 8 of induction chemotherapy and analyze the correlation between day 8 MRD (D8RD) and therapeutic effectiveness. 29 adult patients (13 males and 16 females, aged 16 - 75 years, median 41 years) with AML diagnosed and treated in West China Hospital from September 2009 to June 2010 were analyzed and followed up in the study. The leukemia-associated aberrant immunophenotype (LAIP) of all the patients were detected by multiparameter flow cytometry (FCM) before therapy. The level of MRD in the peripheral blood at day 8 of induction chemotherapy was detected by FCM based on the LAIP. The overall survival curve was drawn by calculation using Kaplan-Meier method using, and the comparison between different groups was carried out by Log-rank test. The results indicated that after first course therapy, the levels of peripheral D8RD in 7 out of 29 AML cases were lower than 0.01% (negative group), and that in another 22 cases were higher than 0.01% (0.08% - 55%, positive group). The sex, age, WBC, LDH, percentage of bone marrow blasts at diagnosis in these groups were not statistically different. 6 cases achieved CR (86%) in D8RD negative group, and also 6 cases achieved CR (27%) in D8RD positive group, CR rate in D8RD negative group was higher than in D8RD positive group (86% vs 27%, P < 0.05). The median follow-up of 29 cases lasted for 15 months; the 1-year overall survival rate of D8RD negative and D8RD positive groups was 100% and 39.4%, respectively (P < 0.01). It is concluded that MRD level in peripheral blood at day 8 of induction chemotherapy is an early index to predict clinical efficacy of induction therapy in AML.