Allogenic hemopoietic stem cell transplants for patients with relapsed acute leukemia: long-term outcome

We assessed the long-term outcome of patients with relapsed acute myeloid (n=86) or acute lymphoid leukemia (n=66), undergoing an allogeneic hemopoietic stem cell transplantation in our unit. The median blast count in the marrow was 30%. Conditioning regimen included total body irradiation (TBI) (10-12Gy) in 115 patients. The donor was a matched donor (n = 132) or a family mismatched donor (n = 20). Twenty-two patients (15%) survive disease free, with a median follow-up of 14 years: 18 are off medications. The cumulative incidence of transplant related mortality is 40% and the cumulative incidence of relapse related death (RRD) is 45%. In multivariate analysis of survival, favorable predictors were chronic graft-versus-host disease (GvHD) (P = 0.0003), donor other than family mismatched (P = 0.02), donor age less than 34 years (P=0.02) and blast count less than 30% (P = 0.07). Patients with all four favorable predictors had a 54% survival. In multivariate analysis of relapse, protective variables were the use of TBI (P = 0.005) and cGvHD (P = 0.01). This study confirms that a fraction of relapsed leukemias is cured with an allogeneic transplant: selection of patients with a blast count <30%, identification of young, human leukocyte antigen-matched donors and the use of total body radiation may significantly improve the outcome.