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[Clinical Study on Dynamic Detection of Minimal Residual Disease in Acute Myeloid Leukemia by Multiparameter Flow Cytometry].

OBJECTIVE
To investigate the prognostic significance of dynamic detection of minimal residual disease (MRD) in patients with acute myeloid leukemia (AML) by 8-color flow cytometry.


METHODS
MRD of 282 AML patients who achieved remission after initial therapy was detected by 8-color flow cytometry. MRD threshold for predicting recurrence was determined by receiver operating characteristic (ROC) curve, and time from MRD-positive to clinical recurrence was analyzed. The differences in overall survival (OS) time and relapse-free survival (RFS) time of patients with different MRD-changes were compared, and the related factors of recurrence in patients with MRD-negative were analyzed by univariate and logistic regression analysis.


RESULTS
ROC curve determined that the MFC-MRD threshold for predicting the recurrence of AML was 0.105%, and the recurrence rate of MRD-positive patients was significantly higher than that of MRD-negative patients [52.45% (75/143 cases) vs 35.97% (50/139 cases), P=0.005]. The patients in MRD persistent positive group and negative to positive group recurred earlier than those in positive to negative group and negative-positive fluctuation group (P<0.005). Survival analysis showed that OS and RFS time of patients with MRD persistent positive were significantly shorter than those of patients with MRD persistent negative, positive to negative, and negative-positive fluctuation (P<0.005). There was no significant difference in OS and RFS between MRD negative to positive group and MRD persistent positive group (P>0.005), either between MRD persistent negative group and MRD positive to negative group (P>0.005). Among 139 MRD-negative patients, 50 recurred. Univariate and logistic regression analysis showed that the risk of recurrence increased with the increase of white blood cells level (95%CI: 1.000-1.013, P=0.045). The risk of recurrence in patients without hematopoietic stem cell transplantation (HSCT) was 9.694 times higher than that in patients who received HSCT (95%CI: 1.720-54.651, P=0.010), and in the high-risk group was 5.848 times higher than that in the low-risk group (95%CI: 1.418-24.121, P=0.015).


CONCLUSION
The prognosis of AML patients with different MRD changes is significantly different. No matter MRD-positive or MRD-negative at the initial remission, dynamic detection of MRD after treatment is more helpful to accurately guide treatment.