title: Characteristics and Survival Outcome Analysis of Extramedullary Involvement in Adult Patients With t(8;21) Acute Myeloid Leukemia.
abstract: Acute myeloid leukemia (AML) with t(8;21)(q22;q22) is classified into a favorable-risk group. Extramedullary (EM) involvement has frequently been reported in this subgroup as resulting in a poor prognosis. However, characteristics or standard treatments of t(8;21) AML with EM involvement (EM-positive t(8;21)) have not yet been elucidated.
  
  
  
  We retrospectively analyzed 154 adult AML patients with t(8;21). Among them, 17 were EM positive and 137 were EM negative at the time of diagnosis. EM involvement was evaluated only when a patient showed suspicious signs or symptoms. All EM-positive patients were treated according to a strategy based on allogeneic hematopoietic cell transplantation (allo-HCT).
  
  
  
  Central nervous system was the most frequently involved site (70.6%). EM-positive t(8;21) was associated with age ≤ 45 years, leukocytosis (≥ 30 × 109/L), and c-kit mutation compared to EM-negative t(8;21) in multivariate analysis. After intensive chemotherapy with or without local therapy, high-risk t(8;21) AML including EM-positive t(8;21) underwent allo-HCT for postremission therapy. Three-year OS (52.3% vs. 60.0%, P = .658) and event-free survival (51.5% vs. 58.0%, P = .496) were not different between the 2 groups. The subgroup of patients who underwent allo-HCT also showed similar outcomes.
  
  
  
  EM-positive t(8;21) was associated with young age, leukocytosis, and c-kit mutation, and central nervous system was frequently involved. Allo-HCT resulted in good outcomes in EM-positive t(8;21).
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sung-Soo
authors.initials: SS
authors.lastname: Park
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jae-Ho
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. Electronic address: cumckim@catholic.ac.kr.
authors.forename: Hee-Je
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Jeon
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sung-Eun
authors.initials: SE
authors.lastname: Lee
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Byung-Sik
authors.initials: BS
authors.lastname: Cho
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Ki-Seong
authors.initials: KS
authors.lastname: Eom
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Yoo-Jin
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Seok
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Chang-Ki
authors.initials: CK
authors.lastname: Min
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Seok-Goo
authors.initials: SG
authors.lastname: Cho
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Kim
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jong-Wook
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Department of Hematology, Catholic Blood and Marrow Transplantation Center, Leukemia Research Institute, Seoul St Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Woo-Sung
authors.initials: WS
authors.lastname: Min
mesh_terms: D000293:Adolescent; D000328:Adult; D018572:Disease-Free Survival; D005260:Female; D006086:Graft vs Host Disease / Q000209:etiology; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult
keywords: Central nervous system; Core-binding factor; Extramedullary; Hematopoietic cell transplantation; c-kit