Background: Extramedullary relapse after allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia is a contributor to post-transplant mortality but risk factors for, and outcomes, are not well characterized. Design and methods: We analyzed 257 consecutive patients receiving allogeneic stem cell transplantation for acute myeloid leukemia at our institution to characterize extramedullary relapse, identify predictive variables and assess outcomes. Results: The 5-year cumulative incidence of isolated extramedullary or marrow relapse was 9% and 29%, respectively. Extramedullary relapse occurred later than marrow relapse and most frequently involved skin and soft tissue. Factors predictive of extramedullary relapse post-transplant included previous extramedullary disease, French-American-British classification M4/M5 leukemia, high risk cytogenetics, and advanced disease status at time of transplant. Children were more likely to develop extramedullary relapse than adults, a finding probably explained by an overrepresentation of extramedullary disease prior to transplant and M4/M5 leukemia in children. Acute graft-versus-host disease was not protective against relapse. Unlike medullary relapse, chronic graft-versus-host disease was not protective against extramedullary relapse. Survival after extramedullary relapse was 30% at 1-yr and 12% at 2-yrs. Conclusions: Extramedullary relapse is a significant contributor to mortality after allogeneic transplantation for acute myeloid leukemia that appears to be resistant to the immunotherapeutic effect of allo-transplantation. Effective strategies for these patients are needed to improve outcomes after transplant.
- Received June 29, 2012.
- Accepted September 12, 2012.
- Copyright © 2012, Ferrata Storti Foundation