AML-487 Prognostic Significance of Residual Disease Detected by Flow Cytometry in Acute Myeloid Leukemia With Normal Karyotype and Negative FLT3-ITD/ D835

Abstract

Complete remission in patients with AML is still cytomorphological, representing a highly heterogeneous state with a wide range of tumor burden and diverse clinical findings. To evaluate prognostic significance of residual disease detected by flow cytometry in acute myeloid leukemia with normal cytogenetics and negative FLT3-ITD/D835. This is a prospective study, spanning a period of five years from January 2017 to December 2021. Our patients were followed for 25 months. The study is carried out in the context of hospitalized care for better management of LAM. We followed 54 adult patients diagnosed with AML according to the 2016 WHO criteria in the hematology and pediatric oncology department of the August 20 Hospital in Casablanca, of which 30 patients achieved complete cytological remission after induction. Any patient presenting a therapeutic failure in post induction and salvage therapy was excluded from the study. After that, we selected patients with normal karyotype for FLT3 gene mutational analysis. Quantification of minimal residual disease (MRD) and leukemic stem cells (LSC) using a six-color Navios type flow cytometer and the cxp acquisition and analysis software. A large panel of monoclonal antibodies was used to determine leukemia-associated immunophenotypes in most patients. Molecular analysis of FLT3-ITD/D835 was performed by PCR/RFLP (restriction fragment length polymorphism). The hypothesis of our study was that the group of patients with favorable and intermediate prognosis will have a relatively better relapse-free survival (RFS) than those with a poor prognosis. The intermediate risk group was predominant with a rate of 83%, of which 67% (20/30) had a normal karyotype. MRD and LSC positivity in this group was predominant with considerable decrease in hematogone count frequency as a marker of good prognosis. Non-mutated FLT3 gene in this group conferred a more improved relapse-free survival compared to that of the negative MRD in all our patients studied. MRD, LSC and are FLT3 gene analysis are powerful prognostic factors for relapse that should be integrated routinely to guide our clinicians in risk stratification, especially in patients with normal karyotype.