Efficacy Of Hematopoietic Stem Cell Transplantation For T-cell Acute Lymphoblastic Leukemia

Objective To investigate the outcomes of hematopoietic stem cell transplantation (HSCT) for T-cell acute lymphoblastic leukemia(T-ALL) and to analysis risk factors of prognosis.Methods A total of 45 patients with T-ALL, who received allo-HSCT or auto-HSCT in transplant center of Institute of Hematology and Blood Disease Hospital from July 2001 to June 2015, were retrospectively analyzed. Overall survival (OS), disease-free survival (DFS), graft-versus-host disease (GVHD), transplant-related mortality (TRM), recurrence rate(RR), and risk factors of survival were analysed. The statistics was performed by software SPSS17.0 and R2.15.0.Results The median age of the 45 patients was 24(10～49), including 29 males and 16 females. There were 33 and 12 patients who underwent allo-HSCT and auto-HSCT, respectively. Only one patient who underwent auto-HSCT died of pulmonary fungal infection at 18 days after transplantation. All the other patients experienced hematopoietic reconstruction. Of the 33 patiens who received allo-HSCT, the median time of nuetrophil and pletlet engraftment was 16 (11～20) days and 20 (11～42) days, respectively. Of the 11 patiens who received auto-HSCT, the median time for nuetrophil and pletlet engraftment was 13 (10～21) days and 16(11～39) days, respectively. The probabilities of aGVHD and grade II-IV aGVHD 100 days post transplant were 57.6%(95% CI 38.6～72.6%) and 24.2%(95% CI 11.2～39.9%), respectively. The median occurrence time of aGVHD was 22 (11～60) days. The probabilities of cGVHD and extensive cGVHD 2 years post transplant were 37.4%(95% CI 10.3～43.1%) and 21.5%(95% CI 8.0～39.3%), respectively. The median occurrence time of cGVHD were 180 (100～552) days. The 3-year OS rates of allo-HSCT and auto-HSCT were (61.9±9.4)% and (54.0±15.4)%,respectively (p=0.586). By univariate analysis,we found that transplant before 2010,white blood cell (WBC)≥100×10/L, no B lineage antigen expression, failed to reach complete remission (CR) after 1 course induction chemotherapy, more than 4 courses of consolidation, poor response at early stage of induction chemotherapy (at least 5% leukemia cells in the bone marrow smear on the 14th day of the induction chemotherapy), no L-asparaginase in the chemotherapy regimens, and pulmonary infection post transplant demonstrated negative effect on OS. In multivariate analysis, the pulmonary infection was the only independent risk factor (HR=7.962,95% CI 1.254～ 50.536, p=0.028). The 3-year DFS rates of allo-HSCT and auto-HSCT were (59.6± 9.3)% and (57.1±14.6)%, respectively (p=0.684). By univariate analysis, transplant before 2010, WBC≥100×109/L, no L-asparaginase in the chemotherapy regimens, and pulmonary infection post transplant demonstrated to be risk factors for DFS. In multivariate analysis, WBC≥100×109/L was the only independent risk factor (HR=0.306,95%CI 0.113～0.829, p=0.020). A total of 9 patients experienced relapse after transplant, including 5 patients in the allo-HSCT group, and 4 patients in the auto-HSCT group. The 3-year relapse rate (RR) was 16.5%(95% CI 5.8 ～31.9%) in the allo-HSCT group, and 34.5%(95%CI 9.4～62.0%) in the auto-HSCT group. There was no significant difference between the two groups (p= 0.171). The median relapse time was 141 (68-332) days. By univariate analysis, we found that no L-asparaginase in the chemotherapy regimens, poor response of induction chemotherapy, more than 30 years old, negative cytomegalovirus (CMV) viremia after transplant were risk factors of relapse. However, none of them was independent risk factor for relapse in multivariate analysis. A total of 8 patients died of transplantion related complications, including 7 patients in allo-HSCT group and 1 patient in auto-HSCT, respectively. The 3-year transplant-related mortality (TRM) of allo-HSCT and auto-HSCT were 23.9%(95% CI 9.9～41.1%) and 8.3%(95%CI 0.4～32.3%), respectively (p=0.339). The median time of TRM was 117 (18～545) days. By univariate analysis, younger than 30 years old, TBI+CY+Flu+Ara-C as conditioning regimen, pulmonary infection and CMV viremia post transplant demonstrated to be risk factors of TRM. But none of them independent risk factor in multivariate analysis.Conclusions allo-HSCT and auto-HSCT are effective treatment for T-ALL. good response at early stage of individual induction chemotherapy, CR after 1 course of induction chemotherapy; L-asparaginase in the chemotherapy regimens, effective prophylaxis and treatment of pulmonary infection after transplant are the keys to improve the outcomes of HSCT for T-ALL.