Comparison Of Unrelated-donor And Sibling-donor Umbilical Cord Blood Transplantation For The Treatment Of Pediatric Patients With Hematological Malignancies

BackgroundAllogeneic hematopoietic stem cell transplantation has been the effective and the only cure method for hematological malignancies.The umbilical cord blood has been the significant alternative donor for the patients who lacking of human leukocyte antigen matched sibling donors and human leukocyte antigen matched unrelated donors.In recent years,umbilical cord blood transplantation has been gradually improved and became a indispensable alternative source of stem cells,which plays an important role on the treatment of pediatric patients with hematological malignancies.Reserving umbilical cord blood has a profound effect on the future development of umbilical cord blood transplantation with the substantial support of national two-child policy in China.ObjectiveTo compare the clinical efficacy of single sibling-donor umbilical cord blood transplantation(SUCBT)and single unrelated-donor UCBT(UUCBT)for the treatment of pediatric patients with hematological malignancies.Methods1.We retrospectively analyzed the clinical data of pediatric patients with hematological malignancies who receiving single-unit sibling-donor UCBT or unrelated-donor UCBT at the hematopoietic stem cell transplantation center of the first affiliated hospital of Zhengzhou University between January 1,1998 and December 31,2019.All of the patients were divided in tow groups named SUCBT group and UUCBT group according to the source of stem cells.2.Both of the groups received myeloablative conditioning regimen,adopting cyclosporine A separately in SUCBT group and CsA combined with mycophenolate mofetil in UUCBT group for GVHD prophylaxis.3.Comparing the time of hematological engraftment,the incidence of GVHD,transplant-related mortality(TRM),5-year overall survival(OS)and 5-year disease-free survival(DFS).4.Statistical description and analysis:All of the related clinical data on disease attributes and efficacy of transplantation adopted SPSS 23.0 software.The estimate of survival rate and depicting survival curves depended on Kaplan-Meier method,and then using Log-rank test to compare the group survival.Results1.There were 37 patients successfully attaining hematological engraftment in all patients,which had the engraftment of 88.1%.The median time of neutrophil engraftment in SUCBT group and UUCBT group were[16 days(11～43 days)vs 20 days(12～45 days),respectively(P=0.350)].The median time of platelet engraftment in two groups were[20 days(15～50 days)vs 28 days(18～56 days),respectively(P=0.805)].There were no remarkable differences in hematological engraftment between them.2.The cumulative incidence of acute graft-versus-host disease(aGVHD)at day-100 in SUCBT group and UUCBT group were[33.3%(5/15)vs 40.9%(9/22),P=0.738].The cumulative incidence of chronic graft-versus-host disease(cGVHD)in two groups were[14.3%(2/14)vs 33.3%(6/18),P=0.412].There were no remarkable differences in terms of the cumulative incidence of aGVHD and cGVHD.3.There were no significant differences with regards to the transplant-related mortality in SUCBT group and UUCBT group[29.4%(5/17)vs 44.0%(11/25),P=0.339].4.There were 4 patients relapsed in SUCBT group and 8 patients relapsed in UUCBT group respectively,which had no significant differences in the incidence of relapse between them[23.5%(4/17)vs 32.0%(8/25),P=0.804].5.There were remarkable differences in 5-year overall survival(OS)[(52.3%±12.3%)vs(27.2%±9.9%),P=0.047],5-year disease-free survival(DFS)[(47.1%±12.1%)vs(23.5%±9.2%),P=0.045]between SUCBT group and UUCBT group.Moreover,the sibling-donor UCBT was significantly better than the unrelated-donor UCBT in long-term OS and DFS.Conclusions1.Umbilical cord blood transplantation is one of the most safe and effective methods for the treatment of pediatric patients with hematological malignancies.The umbilical cord blood is also a crucial alternative donor stem cell sources for them.2.This study confirms that sibling-donor UCBT patients can benefit from long-term survival compared with unrelated-donor UCBT patients.Therefore,in the context of the national two-child policy,it is particularly important to reserve umbilical cord blood for the protection of sibling-donor umbilical cord blood transplantation,and it is worth promoting gradually in clinical practice.