Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

The clinical significance of extramedullary relapse (EMR) of acute myelogenous leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains poorly defined. Here we report the clinical outcomes of patients who underwent allo-HSCT for AML at our institution between 2000 and 2012. A total of 293 patients with AML who underwent allo-HSCT were included. The median duration of follow-up in survivors was 1840 days. Disease status at the time of allo-HSCT was complete remission in 192 patients and nonremission in 101 patients. A total of 110 patients experienced AML relapse after allo-HSCT, including 18 with EMR only, 83 with bone marrow relapse (BMR) only, and 9 with both EMR and BMR. The 5-year cumulative incidence of EMR after allo-HSCT was 9.5%, whereas that of BMR only was 28.9%. In multivariate analysis, peripheral blood stem cell transplantation was associated with an increased risk of EMR. The 2-year overall survival after post-transplantation relapse was 7.5% in patients with BMR only, 11.1% in those with both EMR and BMR, and 27.5% in those with EMR only (P < .05). Although the short-term survival was better in patients with EMR only, they rarely achieved long-term survival. Appropriate strategies for both post-transplantation EMR and BMR are needed.