title: Is extramedullary relapse of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation associated with improved survival?
abstract: OBJECTIVE
  Recent reports have suggested that extramedullary (EM) relapse of acute myeloid leukemia (AML) post-hematopoietic stem cell transplantation (HSCT), unlike isolated bone marrow (BM) relapse, is associated with improved prognosis. We reviewed the outcomes of relapsed AML post-HSCT at our institution to determine whether survival for patients with EM relapse was truly improved in comparison to patients suffering BM relapses treated in a similar (active) way.
  
  
  METHODS
  Outcomes of all 274 allogeneic HSCT performed for adult AML between 2000 and 2010 at our institution were retrospectively reviewed.
  
  
  RESULTS
  As of January 2011, 72 relapses post-HSCT had occurred, including 64 BM relapses (89%), two concomitant BM and EM relapses (3%), and six EM relapses alone (8%). EM relapses occurred significantly later post-HSCT than BM relapses (median 25.2 vs 3.9 months, respectively; P = 0.001). Patients suffering an EM relapse were significantly more likely to receive active therapy at relapse (7/8; 88%) than those suffering a BM relapse alone (28/64; 44%; P = 0.026). When survival analysis was restricted to outcomes of patients treated actively (i.e., with curative intent), no difference in outcome between EM and BM relapses was observed (median survival 13.5 vs 8 months for EM vs BM relapses, respectively, P = 0.44).
  
  
  CONCLUSIONS
  Our results suggest that EM relapse post-HSCT has similar outcomes to BM relapses treated in a similar way. Furthermore, choice of therapy at relapse appears related to the time post-HSCT that the relapse occurs, with BM relapses occurring significantly earlier post-HSCT than relapses at EM sites.
authors: Department of Haematology, Royal Brisbane and Women's Hospital, Queensland, Australia.
authors: Cameron
authors: C
authors: Curley
authors: Simon
authors: S
authors: Durrant
authors: Glen A
authors: GA
authors: Kennedy
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D016019:Survival Analysis; D014184:Transplantation, Homologous; D016896:Treatment Outcome; D055815:Young Adult
keywords: acute myeloid leukemia; allogeneic stem cell transplantation; extramedullary; relapse; survival