High-Dose Total Body Irradiation and Myeloablative Conditioning before Allogeneic Hematopoietic Cell Transplantation: Time to Rethink?

• Over the last decade Long-term survival significantly improved after allo-HCT.
• Long-term survivorship is associated with significant chronic morbidities.
• High dose TBI and myeloablative conditioning regimens are major risk factors.
• Improved conditioning and preventive practices will allow decreasing their onset.

Over the last decade, the care of patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) has significantly improved, leading to a decrease in deaths related to allo-HCT as well as improved long-term survival. However, for many patients, long-term survivorship is associated with a substantial burden of chronic morbidities. Indeed, malignant and nonmalignant late complications after allo-HCT are numerous and usually multifactorial, with all organs and tissues a potential target. In many cases, these long-term side effects are associated with the use of high-dose total body irradiation, myeloablative conditioning regimens, and the onset of chronic graft-versus-host disease. It appears to be essential to change the natural history of these late effects. This requires the introduction of improved conditioning regimens and the development of lifelong monitoring controls, patient counseling, and preventative treatment measures. This approach will allow us to pursue our efforts to improve patient outcome.