2021 Volume 58 Issue 2 Pages 103-110
The overall survival (OS) rate of pediatric patients with acute leukemia undergoing allogeneic hematopoietic cell transplantation (HCT) in the first or second complete remission (CR) is in the range of 60% to 70%. By contrast, the OS rates of patients undergoing allogeneic HCT in the third and subsequent CR or in non-CR remain unsatisfactory, suggesting the need to further decrease the risk of post-HCT relapse. On the other hand, long-term survivors of allogeneic HCT are at increased risk of developing late adverse effects, which are associated with high-dose total body irradiation (TBI) or high-dose chemotherapy used in myeloablative conditioning regimens, or with chronic graft-versus-host disease. Intensification of the conditioning regimen to reduce the risk of relapse after HCT increases transplant-related mortality, which cannot improve the transplantation outcomes. Instead, several therapeutic approaches are ongoing, aiming for the reduction of the pre-HCT tumor burden and the prevention or early intervention of post-HCT relapse. Non-TBI, non-busulfan reduced-toxicity conditioning will contribute to the improvement of long-term transplantation outcomes by reducing late adverse effects. Measurement of minimal residual disease by highly accurate assays is required to select these pre- and post-HCT treatments and assess their efficacies.
