Reduced Intensity Conditioning Before Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia in Complete Remission and Myelodysplastic Syndrome: A Meta-Analysis of Randomized Controlled Trials

BackgroundReduced intensity conditioning (RIC) before allogeneic hematopoietic stem cell transplantation (allo-HSCT) was reported had the same overall survival (OS) as myeloablative conditioning (MAC) for acute myeloid leukemia (AML) in complete remission (CR) and myelodysplastic syndrome (MDS) but results in different studies are contradictory. Therefore, we conducted a meta-analysis according to the PRISMA 2009 guidelines to confirm the efficacy and safety of RIC vs. MAC for AML in CR and for MDS.MethodsPubMed, Web of Science, Embase, Cochrane central, related websites, major conference proceedings were searched, and related journals were hand-searched from Jan 1, 1980 to July 1, 2020 for studies comparing RIC with MAC before the first allo-HSCT in patients with AML in CR or MDS. Only RCTs were included. OS was the primary endpoint and generic inverse variance method was used to combine hazard ratio (HR) and 95% CI.ResultsWe retrieved 7770 records. Six RCTs with 1413 participants (711 in RIC, 702 in MAC) were included. RIC had the same OS (HR = 0·95, 95% CI 0·64–1·4, P = 0·80) and cumulative incidence of relapse as MAC (HR = 1·18, 95% CI 0·88–1·59, P = 0·28). RIC reduced non-relapse mortality more than total body irradiation/busulfan based MAC (HR = 0·53, 95% CI 0·36–0·80, P = 0·002).ConclusionRIC also had similar long-term OS and graft failure as MAC. RIC is also a good choice for patients with AML in CR or MDS.