title: The applicability of the WHO classification in paediatric AML. A NOPHO-AML study.
abstract: The World Health Organization (WHO) classification of myeloid leukaemia was revised in 2008. It incorporates newly recognized entities and emphasizes the pivotal role of cytogenetic abnormalities. The aim of this study was to evaluate the usability of the WHO classification when applied to a large population-based paediatric acute myeloid leukaemia (AML) cohort. We included children diagnosed with de novo AML, 0-18 years of age from the Nordic countries and Hong Kong from 1993 to 2012. Data were retrieved from the Nordic Society for Paediatric Haematology and Oncology AML database and patients classified according to the WHO 2008 classification. A successful karyotype was available in 97% of the cases. AML with recurrent genetic abnormalities were present in 262 (41%) and 94 (15%) were classified as AML with myelodysplasia-related changes (AML-MDS). WHO classifies patients with monosomy 7 and del(7q) into one group. We found that -7 (n = 14) had significantly poorer outcome than del(7q) (n = 11); 5-year event-free survival 26% vs. 67%, (P = 0·02), and 5-year overall survival 51% vs. 90%, (P = 0·04). The largest group was the highly heterogeneous AML not otherwise specified (NOS) (n = 280) (44%). In conclusion, the WHO classification allocated 15% to AML-MDS, 44% to NOS and grouped together entities with clearly different outcome, therefore limiting the applicability of the current WHO classification in children with AML.
authors.affiliation: Department of Paediatrics, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Julie D
authors.initials: JD
authors.lastname: Sandahl
authors.affiliation: Cancer Cytogenetics Laboratory, Department of Haematology Aarhus University Hospital, Aarhus, Denmark.
authors.forename: Eigil
authors.initials: E
authors.lastname: Kjeldsen
authors.affiliation: Institution for Clinical Sciences, Department of Paediatrics, Queen Silvia Children's Hospital, Gothenburg, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Abrahamsson
authors.affiliation: Department of Paediatrics, Queen Mary Hospital and Hong Kong Paediatric Haematology & Oncology Study Group (HKPHOSG), Hong Kong, China.
authors.forename: Shau-Yin
authors.initials: SY
authors.lastname: Ha
authors.affiliation: Department of Paediatrics, University Hospital, Lund, Sweden.
authors.forename: Jesper
authors.initials: J
authors.lastname: Heldrup
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Jahnukainen
authors.affiliation: Department of Paediatrics, Landspitalinn, Reykjavik, Iceland.
authors.forename: Ólafur G
authors.initials: ÓG
authors.lastname: Jónsson
authors.affiliation: Department of Paediatrics and Adolescent Medicine, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Birgitte
authors.initials: B
authors.lastname: Lausen
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors.forename: Josefine
authors.initials: J
authors.lastname: Palle
authors.affiliation: Department of Paediatric Medicine, Oslo University Hospital, Oslo, Norway.
authors.forename: Bernward
authors.initials: B
authors.lastname: Zeller
authors.affiliation: Department of Medical Biosciences, Clinical Genetics, Umeå University Hospital, Umeå, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Forestier
authors.affiliation: Department of Paediatrics, Aarhus University Hospital Skejby, Aarhus, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Hasle
mesh_terms: D000293:Adolescent; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D020732:Cytogenetic Analysis / Q000379:methods; D006723:Hong Kong; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000235:genetics / Q000401:mortality; D010372:Pediatrics; D012537:Scandinavian and Nordic Countries
keywords: World Health Organization; acute myeloid leukaemia; classification; leukaemia; paediatrics