Highlighting the Prognostic Importance of Measurable Residual Disease Amongst Acute Myeloid Leukemia Risk Factors

Objective The optimal timing of measurable residual disease (MRD) evaluation in acute myeloid leukemia (AML) patients has not been well-defined yet. We aimed to investigate the impact of MRD in pre and post allogeneic hematopoietic stem cell transplantation (AHSCT) periods on prognostic parameters. Materials and methods Seventy-seven AML patients who underwent AHSCT in complete morphological remission were included. MRD analyses were performed by 10 color multiparameter flow cytometer and 10-4 was defined as positive. Relapse risk and survival outcomes were assessed based on pre- and post-AHSCT MRD positivity. Results The median age of the patients was 46 (18-71) years, of whom 41 (%53.2) were male and 36 (%46.8) were female. The median follow-up after AHSCT was 12.2 months (range 0.2-73.0). The 2-year overall survival (OS) in the entire cohort was 37.0%, with a significant difference between patients who were MRD-negative and MRD-positive before AHSCT, estimated as 63.0% vs. 16.0%, respectively (p=0.005). MRD positivity on +28 days post-AHSCT was also associated with a significantly inferior 2-year OS, when compared to MRD negatives (p=0.03). The risk of relapse at 1-year was 2.4 times [95% confidence interval (CI): 1.1-5.6; p=0.04] higher in the pre-SCT MRD-positive group when compared to the MRD-negative, regardless of other transplant related factors, including pre-AHSCT disease status [i.e.; complete remission 1 (CR1) and CR2]. Event free survival (EFS) was significantly shorter in patients who were pre-AHSCT MRD-positive (p=0.016). Post-AHSCT MRD positivity was also related to an increased relapse risk. OS and EFS were significantly inferior among patients MRD-positive on +28 days post-AHSCT (p=0.03 & p=0.019). Conclusion Our results indicate the importance of MRD before and after AHSCT independent of the other factors.