Long-Term Outcomes After Allogeneic Stem Cell Transplantation

Allogeneic stem cell transplantation (AlloSCT) with hematopoietic stem cells derived from donor peripheral blood (PB) or bone marrow is a curative option for patients with high-risk or relapsed hematologic malignancies, but procedure-related morbidity and mortality may be increased in the years following the procedure. A retrospective cohort study is now reported from three U.S. transplant centers, assessing outcomes for AlloSCT patients who survived 2 years or more following the procedure, performed from 1974 through 2014. The investigators assessed all-cause disease recurrence- and non–recurrence-related mortality. The latter included deaths from infections, second primary malignancies, and cardiopulmonary disease.

Among the 4741 patients, myeloid malignancies accounted for about half of primary diagnoses and acute lymphoblastic leukemia for about 20%. Patients treated from 1974 through 1989 were relatively young, had predominately marrow grafts, had more matched sibling transplants, and had limited options for preventing/treating graft-versus-host disease (GVHD). Those treated from 1990 through 2004 had increased use of unrelated donor transplants and PB stem cell grafts and reduced-intensity conditioning regimens. Those treated from 2005 through 2014 tended to be older, and more received PB grafts and cord blood transplants. Improved HLA typing methodologies were used during the time periods of the second two cohorts.

While recurrence-related mortality plateaued after 10 years of follow-up, nonrelapse mortality (particularly from cardiopulmonary causes) continued to increase with follow-up. Nonrelapse mortality was improved for the most recent cohort, but only for patients younger than 18 and those receiving donor marrow rather than PB. Overall, AlloSCT patients had 8.8-fold higher mortality than the general population and a relative reduction in life expectancy of 8.7 years. Chronic GVHD was associated with infection- and pulmonary-related deaths; older age at time of transplant was associated with infection-related death.