Current Status and Perspectives of Irradiation-Based Conditioning Regimens for Patients with Acute Leukemia Undergoing Hematopoietic Stem Cell Transplantation

Abstract

Acute myeloid leukemia and acute lymphoblastic leukemia are the most common indications for allogeneic hematopoietic stem cell transplantation. Total body irradiation (TBI) is an important part of conditioning regimens. TBI-based regimens offer advantages in sanctuary sites but are associated with significant risks of early and late side effects, including pulmonary toxicity, growth retardation, and second malignancy. TBI is also associated with technical problems, such as dose heterogeneity. With evolving techniques in radiation oncology, it is possible to focus the dose to the entire skeleton while sparing the rest of the body. This technique is called total marrow irradiation (TMI). TMI is able to deliver the same or higher doses to bone marrow while reducing toxicity. With the success of TMI, we are moving toward ultra-personalized conditioning. We review the clinical role of the irradiation-based regimens currently in clinical use, emphasizing on their strengths and limitations. Novel technologies with targeted irradiation accompanied by the modern imaging techniques and increased knowledge of the disease process can help us achieve our goal of maximum response with minimum toxicity.

Allogeneic peripheral blood stem cell transplantation with anti-thymocyte globulin versus allogeneic bone marrow transplantation without anti-thymocyte globulin

“…We elected to restrict the analyses of patients given grafts after myeloablative conditioning since it was a inclusion criteria in most phase III ATG studies, although many AML patients are nowadays transplanted following reduced-toxicity regimens. 20,21 Several observations can be made.…”

Fractionated gemtuzumab ozogamicin in association with high dose chemotherapy: a bridge to allogeneic stem cell transplantation in refractory and relapsed acute myeloid leukemia

“…5 Allogeneic hematopoietic stem cell transplantation (allo-HCT) is the only salvage option with curative potential in these two scenarios. 6 However, disease status at transplant remains one of the main prognostic factors. 7,8 There is no consensus on the optimum salvage therapy which may be used as a bridge to allo-HCT.…”

Two compound techniques for total body irradiation

“…High-dose total body irradiation (TBI) is a radiotherapy modality in which the whole body is irradiated. Typically, the body is irradiated to a mean of 12–15 Gray (Gy) in 8–12 fractions with one to three fractions a day over three to six days [1] , [2] , [3] , [4] , [5] , [6] . This modality is a part of the treatment of systemic hematologic malignancies [1] , [2] , [3] , [4] , [5] , [7] .…”