[Autologous versus unrelated donor stem cell transplantation for adults with primary acute myeloid leukemia in first remission]

Objective: To compare differences of autologous and unrelated donor stem cell transplantation (auto-HSCT and URD-HSCT) for adults with primary acute myeloid leukemia (AML) in first complete remission (CR(1)) from a single center and to investigate the appropriate patients for the 2 types of transplant. Methods: In this retrospective investigation, we studied adults with primary AML who received auto-HSCT and URD-HSCT from March 2008 to November 2018. Overall survival (OS) , leukemia-free survival (LFS) , relapse, transplant-related mortality (TRM) , and hematopoietic reconstitution were compared along with the prognostic value of cytogenetics. Results: A total of 147 adult patients were enrolled in this study (n=87 for auto-HSCT and n=60 for URD-HSCT) . Baseline characteristics were comparable between the 2 groups. The accumulative neutrophil engraftment rate at +30 days was not statistically different between the 2 groups[92.6% (95% CI 86.9%-98.3%) vs 98.3% (95% CI 95.0%-100.0%) , P=0.270], whereas the accumulative platelet engraftment rate at +60 days was significantly lower in the auto-HSCT group[83.6% (95% CI 75.8%-91.4%) vs 93.3% (95% CI 87.0%-99.6%) , P<0.001]. In patients undergoing URD-HSCT, the accumulative incidences of acute GVHD (aGVHD) and grade Ⅱ-Ⅳ aGVHD were 56.7% (95% CI 43.0%-68.2%) and 16.7% (95% CI 8.5%-27.2%) , and the incidences of chronic GVHD (cGVHD) and extensive cGVHD were 33.3% (95% CI 21.7%-45.4%) and 15.0% (95% CI 7.3%-25.2%) , respectively. After a median follow-up of 53.8 (0.8-127.8) months, patients in the 2 groups demonstrated comparable OS and LFS at 5 years after transplant[71.7% (95% CI 61.7%-81.7%) vs 67.8% (95% CI 55.8%-79.8%) , P=0.556; 64.6% (95% CI 54.4%-74.8%) vs 68.1% (95% CI 56.3%-79.9%) , P=0.642]. Patients in the auto-HSCT group showed significantly higher incidence of relapse at 5 years after transplant[31.9% (95% CI 22.2%-42.1%) vs 15.1% (95% CI 7.4%-25.6%) , P=0.015] and significantly lower incidence of TRM[3.4% (95% CI 0.9%-8.9%) vs 16.7% (95% CI 8.5%-27.2%) , P=0.006] compared with the URD group. HLA mismatching had no effects on the incidences of hematopoietic reconstitution, GVHD, OS, LFS, relapse, and TRM. Patients of cytogenetically favorable and intermediate risk demonstrated comparable OS and LFS after auto-HSCT and URD-HSCT, while patients of poor risk had significantly higher relapse and lower LFS after auto-HSCT. Conclusions: In this study, adults with primary AML in CR(1) demonstrated relatively higher relapse but lower TRM after auto-HSCT, resulting in comparable survival to that of URD-HSCT. In the absence of matched sibling donors, patients of cytogenetically poor risk should receive URD-HSCT in order to achieve lower relapse and better survival.