Is it appropriate to offer allogeneic hematopoietic stem cell transplantation to patients with primary refractory acute myeloid leukemia?

Although continued advances have been made in the treatment of acute myeloid leukemia (AML), approximately 20 - 30% of patients will never achieve a remission. For these patients with primary refractory AML, the only curative option remains an allogeneic stem cell transplant. Allogeneic transplantation provides the ability to administer myeloablative doses of chemotherapy or chemoradiotherapy, as well as the advantage of a possible graft-versus-leukemia effect. Difficulty in interpreting the literature is due to selection bias, in particular, the varying definitions of primary refractory disease with respect to the morphological criteria and the number of induction regimen required before being defined as being refractory. Regardless, it is a procedure with high treatment-related mortality and risk of relapse. Most studies demonstrate an event-free survival of 10 - 20% at 5 years. Predictive factors of outcome include blast cell count in the marrow, karyotype, the number of prior regimen, age, performance status and availability of a related donor. These prognostic factors should be considered prior to offering allogeneic transplantation for primary refractory AML. Those patients with many favorable prognostic factors and an HLA-matched related donor available would be the best candidate for the procedure. Those with many poor prognostic factors and only an unrelated donor available may be better served by being offered palliation or being enrolled in investigational studies.