Achieving stringent CR is essential before reduced-intensity conditioning allogeneic hematopoietic cell transplantation in AML.
Reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (allo-HCT) can cure patients with AML in CR. However, relapse after RIC allo-HCT may indicate heterogeneity in the stringency of CR. Strict definition of CR requires no evidence of leukemia by both morphologic and flow cytometric criteria. We re-evaluated 85 AML patients receiving RIC allo-HCT in CR to test if a strict definition of CR had direct implications for the outcome. These patients had leukemia immunophenotype documented at diagnosis and analyzed at allo-HCT. Eight (9.4%) had persistent leukemia by flow cytometric criteria at allo-HCT. The patients with immunophenotypic persistent leukemia had a significantly increased relapse (hazard ratio (HR): 3.7; 95% confidence interval (CI): 1.3-10.3, P=0.01) and decreased survival (HR: 2.9; 95% CI: 1.3-6.4, P<0.01) versus 77 patients in CR by both morphology and flow cytometry. However, the pre-allo-HCT bone marrow (BM) blast count (that is, 0-4%) was not significantly associated with risks of relapse or survival. These data indicate the presence of leukemic cells, but not the BM blast count affects survival. A strict morphologic and clinical lab flow cytometric definition of CR predicts outcomes after RIC allo-HCT, and therefore is critical to achieve at transplantation.
1] Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, USA [2] Blood and Marrow Transplant Program, University of Minnesota, Minneapolis, MN, USA.
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Ustun
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Wiseman
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Defor
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Yohe
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Linden
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Oran
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Burke
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Warlick
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Miller
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Weisdorf
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000601:surgery / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual / Q000601:surgery / Q000628:therapy*; D011379:Prognosis; D012189:Retrospective Studies; D019172:Transplantation Conditioning / Q000379:methods*; D014184:Transplantation, Homologous; D016896:Treatment Outcome; D055815:Young Adult