Relative impact of residual cytogenetic abnormalities and flow cytometric measurable residual disease on outcome after allogeneic hematopoietic cell transplantation in adult acute myeloid leukemia

Measurable residual disease (MRD) before hematopoietic cell transplantation (HCT) is an independent established prognostic factor in patients with acute myeloid leukemia (AML). Several methods exist to evaluate the presence of residual leukemia cells, but how these are used best in combination is unclear. In order to examine how residual cytogenetic abnormalities and MRD testing by multiparameter flow cytometry (MFC) may refine risk assessment before HCT, we analyzed 506 adults with cytogenetically abnormal AML who underwent both routine karyotyping and MFC MRD testing before receiving a first allograft while in morphologic remission. Testing for residual cytogenetic abnormalities and MFC MRD identified four groups of patients with differential relapse-free survival (RFS) (hazard ratio [HR]=1.63 for Cytoabnormal/MFCnegative [P=0.01, n=63], HR=3.24 for Cytonormal/MFCpositive [P