Redefining Transplant in Acute Leukemia

Assigning the correct treatment to those with acute leukemia is challenging and requires careful assessment of both the disease and the patient. Our ability to assign relapse risk to disease is evolving and incorporates cytogenetics, molecular lesions, and assessment of minimal residual disease after initial treatment. Allogeneic hematopoietic progenitor cell transplantation (alloHCPT) is one of the most efficacious treatments available to the physician. In adult acute lymphoblastic leukemia (ALL) despite the treatment risk, patients with a matched sibling who achieve CR should be referred for transplant. Prospective trials investigating the role of unrelated donors are in progress. There is little prospective evidence, but nonetheless encouraging data, to support referring older patients for alloHPCT using reduced intensity conditioning (RIC) regimens. In acute myeloid leukemia (AML), all high-risk patients and the majority of intermediate-risk patients with a matched sibling should be offered alloHPCT in CR1. In addition there is evidence that some patients previously assigned as good-risk would benefit from sibling transplant. Use of unrelated donors will expand the numbers eligible for transplant and should be considered when a matched-sibling is not available particularly in high-risk patients. Similarly to ALL, the use of RIC is allowing transplantation to be offered to those deemed too old or unfit for myeloablative conditioning. The importance of enrolling patients into suitable prospective clinical trials cannot be overstated.