title: International Classification of Childhood Cancer, third edition.
abstract: BACKGROUND
  The third edition of the International Classification of Diseases for Oncology (ICD-O-3), which was published in 2000, introduced major changes in coding and classification of neoplasms, notably for leukemias and lymphomas, which are important groups of cancer types that occur in childhood. This necessitated a third revision of the 1996 International Classification of Childhood Cancer (ICCC-3).
  
  
  METHODS
  The tumor categories for the ICCC-3 were designed to respect several principles: agreement with current international standards, integration of the entities defined by newly developed diagnostic techniques, continuity with previous childhood classifications, and exhaustiveness.
  
  
  RESULTS
  The ICCC-3 classifies tumors coded according to the ICD-O-3 into 12 main groups, which are split further into 47 subgroups. These 2 levels of the ICCC-3 allow standardized comparisons of the broad categories of childhood neoplasms in continuity with the previous classifications. The 16 most heterogeneous subgroups are broken down further into 2-11 divisions to allow study of important entities or homogeneous collections of tumors characterized at the cytogenetic or molecular level. Some divisions may be combined across the higher-level categories, such as the B-cell neoplasms within leukemias and lymphomas.
  
  
  CONCLUSIONS
  The ICCC-3 respects currently existing international standards and was designed for use in international, population-based, epidemiological studies and cancer registries. The use of an international classification system is especially important in the field of pediatric oncology, in which the low frequency of cases requires rigorous procedures to ensure data comparability.
authors.affiliation: International Agency for Research on Cancer, Lyon, France. steliarova@iarc.fr
authors.forename: Eva
authors.initials: E
authors.lastname: Steliarova-Foucher
authors.forename: Charles
authors.initials: C
authors.lastname: Stiller
authors.forename: Brigitte
authors.initials: B
authors.lastname: Lacour
authors.forename: Peter
authors.initials: P
authors.lastname: Kaatsch
mesh_terms: D001932:Brain Neoplasms / Q000145:classification; D002648:Child; D006801:Humans; D038801:International Classification of Diseases; D007938:Leukemia / Q000145:classification; D008223:Lymphoma / Q000145:classification; D009190:Myelodysplastic Syndromes / Q000145:classification; D009196:Myeloproliferative Disorders / Q000145:classification; D009369:Neoplasms / Q000145:classification*; D012042:Registries; D013125:Spinal Neoplasms / Q000145:classification