Prognostic Factors Of Allogeneic Hematopoietic Stem Cell Transplantation In The Treatment Of Refractory/relapsed Acute Myeloid Leukemia

Objective:To investigate the prognostic factors of patients with refractory/relapsed acute myeloid leukemia(r/r AML)who underwent allogeneic hematopoietic stem cell transplantation(allo-HSCT).Methods:The clinical data of 77 patients with r/r AML who underwent allo-HSCT in the Department of Hematology of Zhejiang Provincial People’s Hospital from January 1,2013 to August 31,2021 were collected,and the follow-up time was up to December 31,2021.The primary endpoints were non-relapsing mortality(NRM),2-year overall survival(OS)and 2-year disease-free survival(DFS)after allo-HSCT.DFS),cumulative relapse rate,and the risk factors of prognosis were analyzed,such as the patient’s age,gender,white blood cell count at first diagnosis,relapse before transplantation,the length of disease before transplantation,disease status before transplantation,conditioning regimen,and the number of infused MNC and CD34~+cells.Results:All 77 r/r AML patients included in the study completed hematopoietic reconstitution except 1 case of transplantation failure.The median time of neutrophil and platelet engraftment were 14(9,25)days and 16(9,48)days,respectively.The cumulative NRM after allo-HSCT was 20.8%(16/77).Twenty-six patients relapsed after allo-HSCT with a median relapse time of 5(1,67)months and a cumulative relapse rate of 33.8%(26/77).The 2-year overall survival(OS)rate of 77 r/r AML patients was 54.5%,and the 2-year disease-free survival(DFS)rate was 49.4%.The results of univariate analysis showed that the cytogenetic abnormalities and/or abnormal chromosome before transplantation,the number of infused MNC<6.9×10~8/kg and II-IV a GVHD during transplantation were poor prognostic factors for OS and DFS.The results of multivariate analysis showed that the cytogenetic abnormalities and/or abnormal chromosome before transplantation,the number of infused MNC<6.9×10~8/kg and II-IV a GVHD were independent prognostic factors for OS(HR=0.377,95%CI:0.191-0.743,P=0.005;HR=0.502,95%CI:0.257 0.982,P=0.044;HR=1.980,95%CI:0.999 3.926,P=0.05)and DFS(HR=0.401,95%CI:0.302 0.792,P=0.009;HR=0.524,95%CI:0.267-1.027,P=0.05;HR=1.819,95%CI:0.921-3.592,P=0.45).Conclusion:allo-HSCT was an effective treatment for refractory/relapsed AML,and the long-term survival rate(5-year OS rate)was 42.8%.Achieving CR before transplantation as much as possible can enhance the efficacy of transplantation and reduce the recurrence rate after transplantation.However,in order to achieve CR,we should not repeat ineffective chemotherapy repeatedly and miss the best opportunity for transplantation.Therefore,haploidentical allo-HSCT can be used for relapsed/refractory AML patients who cannot be matched to a matched sibling donor.