[Prognostic significance of flow cytometric minimal residual disease in acute myeloid leukemia during aplasia]

Objective: To investigate the impact of minimal residual disease (MRD) by multiparameter flow cytometry (MPFC) during aplasia on efficacy and prognosis of de novo acute myeloid leukemia (AML) (non M(3)) patients. Methods: The MRD data by 8-color MPFC during aplasia (day 14-15 of induction therapy) in 85 de novo AML (non M(3)) patients and the MRD impact on efficacy and prognosis were retrospectively analyzed. Results: Data of 85 patients, including 42 males (49.4%) and 43 females (50.6%) , were collected, with a median age of 35 (15-54) years. The median MRD by MPFC during aplasia was 0.58% (0-81.11%) , and 70 (82.4%) patients achieved complete remission (CR) after first induction chemotherapy. The cutoff of MRD by receiver operating characteristic (ROC) analysis was 2.305% (Se= 0.867, Sp=0.800) . The CR rate after one course was significantly higher in patients with MRD<2.305% [96.6% (56/58) ]than in patients with MRD≥2.305%[51.9% (14/27) ] (χ(2)=22.348, P<0.001) ; no significant difference with respect to relapse-free survival rate (χ(2)=1.08, P=0.299) or overall survival rate (χ(2)=0.42, P=0.516) could be demonstrated for the comparison of the two groups. Multivariates analysis showed MRD divided by 2.305% was the only independent prognostic factor for CR after one course (OR= 21.560, 95% CI 4.129-112.579, P<0.001) . Conclusion: Flow cytometric MRD divided by 2.305% during aplasia could be a predictor of efficacy after first induction therapy in AML patients.