Reduced Intensity versus Full Myeloablative Conditioning in Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia

Abstract

Introduction: Allogeneic hematopoietic stem cell transplantation (HSCT) has been reported to be a successful curative treatment in AML patients. Myeloablative conditioning (MAC) is used more frequent as a preparing regimen. This study attempts to compare the outcome of patients who has received MAC and reduced- intensity conditioning (RIC).
Methods: Totally, 618 patients with AML underwent HSCT at our center between 1991 and 2011. Of these, 564 received MAC (Busulfan plus Cyclophosphamide) and 54 patients received RIC consisting of Fludarabine and Busulfan. Patients with suitable performance were assigned in the MAC study group while patients who did not meet these criteria were assigned to the RIC group.
Results: The median age at transplantation was 27 years for MAC and 30 years for RIC group (P value= 0.12). The median follow-up of survivors was 1.75 years for MAC and 4.5 years for RIC. The 3-year OS for MAC and RIC groups was 74.2% and 80.7% (P value= 0.75), respectively. The 3-year DFS was 67.2% for MAC and 69.7% for RIC, (P value= 0.73). The 3-year incidence of relapse for MAC and RIC groups was 16.80% and 26.40%, respectively (P value= 0.05).
Conclusion: the results of the study showed borderline significance (P value=0.05) for incidence of relapse between MAC and RIC groups. However, to make accurate results longer follow up is required. No significant difference in OS and DFS was found between two groups. Further long- term follow- up of more cases is necessary to confirm this difference statistically. Our results indicated that the introduction of RIC allogeneic HSCT for AML patients, especially in elderly, was safe and feasible.