Comparison of total body irradiation plus cyclophosphamide with busulfan plus cyclophosphamide as conditioning regimens in patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplant

Conditioning regimens used during stem cell transplant provide prolonged control or cure of the disease in patients with acute lymphoblastic leukemia (ALL). In this study, we present a comparison of treatment results for 95 patients with ALL who underwent allogeneic hematopoietic stem cell transplant (AHSCT) with total body irradiation plus cyclophosphamide (TBI + Cy) or busulfan plus cyclophosphamide (Bu + Cy) as conditioning regimen. Median age was 25 (range: 9-54) years. Median follow-up was 24 (range: 3-107) months. Median overall survival (OS) was found to be 29 months. Median event-free survival (EFS) was 9 months. Median OS was 37 months in the TBI + Cy arm, while it was 12 months in the Bu + Cy arm, suggesting a significant advantage favoring the TBI + Cy arm (p = 0.003). Median EFS was 13 months in the TBI + Cy arm, while it was 4 months in the Bu + Cy arm, indicating a significant difference (p = 0.006). In univariate and multivariate analysis, it was found that high OS and EFS were significantly correlated with TBI + Cy conditioning regimen and lack of transplant-related mortality (p < 0.05). The TBI + Cy conditioning regimen was found to be superior to the Bu + Cy regimen in patients with ALL undergoing AHSCT regarding both OS and EFS.