OBJECTIVETo investigate the therapeutic effects of the conditioning regimen with busulfan plus cyclophosphamide (BU+CY) or total body irradiation plus cyclophosphamide (TBI+CY) on haploidentical stem cell transplantation (HSCT) in hematologic malignancy.

METHODSThe clinical outcomes of 77 HSCT recipients with hematologic malignancy from January 2001 to December 2010, including 21 AML, 33 ALL, 19 CML and 4 MDS were retrospectively evaluated. Among them, 65 patients obtained complete remission (CR) and 12 non-remission (NR) before transplantation; 39 patients received conditioning regimen with BU+CY, and 38 with TBI+CY.

RESULTSThere were no statistically significant differences in hematopoietic reconstitution, disease free survival (DFS), and transplant- related mortality (TRM) between two groups. The estimated 3- years overall survival (OS) was 56.4% for BU+CY and 31.6% for TBI + CY (P=0.0283). The overall relapse rate was similar between two groups (15.4% vs 34.2%; P=0.1538). However, the accumulative probability of relapse at 1-year was significantly lower in BU+CY than that in TBI+CY group (2.56% vs 26.67%; P=0.0116). The incidence of grade II-IV graft-versus-host disease (GVHD) was similar between two regimens (20.5% in BU+CY group and 18.4% in TBI+CY group; P=0.8168). The incidence of chronic GVHD (cGVHD) was higher in the TBI+CY group than that of BU+CY group (84.6% vs 41.1%; P=0.0007). The extensive GVHD obtained the similar outcome (30.8% vs 10.5%; P=0.0416).

CONCLUSIONPatients using BU+CY as conditioning regimen before transplant could obtain a better 3 year OS and lower short-term relapse rate. The TBI+CY conditioning regimen could significantly increase the incidence of cGVHD without increasing the acute GVHD. BU+CY conditioning regimen could be used for HSCT, but the attention should be paid to prevent the related hemorrhagic cystitis.