title: Degree-of-spread artefact in the New South Wales Central Cancer Registry.
abstract: OBJECTIVE
  To describe a data artefact in degree-of-spread at first presentation in the New South Wales Central Cancer Registry (NSW CCR), the only Australian cancer registry that records degree-of-spread data for all solid tumours.
  
  
  METHODS
  Trends in the proportions of cancer cases diagnosed annually over 1972-2004 by degree-of-spread categories of localised, regional, distant and unknown were calculated for each major cancer type.
  
  
  RESULTS
  Excepting breast cancer and melanoma, the proportion of localised cancer cases reported from 1993-1998 was approximately 5% lower than expected, and was mirrored by an artefactual increase in unknown degree-of-spread cases.
  
  
  CONCLUSIONS
  This artefact was caused by the introduction of the Electronic Notification System and cannot easily be remedied retrospectively. However, regional and distant categories of degree-of-spread in the NSW CCR data are reliably recorded for the 1972-2004 period.
  
  
  CONCLUSIONS
  It is important that past and present cancer data users are notified and understand the quality issues with NSW CCR degree-of-spread data, and use it as recommended to avoid anomalous results or conclusions.
authors.affiliation: Cancer Institute NSW, Australia.
authors.forename: Helen
authors.initials: H
authors.lastname: Barraclough
authors.forename: Stephen
authors.initials: S
authors.lastname: Morrell
authors.forename: Maria
authors.initials: M
authors.lastname: Arcorace
authors.forename: Heather J
authors.initials: HJ
authors.lastname: McElroy
authors.forename: Deborah F
authors.initials: DF
authors.lastname: Baker
mesh_terms: D003937:Diagnosis, Differential; D006751:Hospital Information Systems / Q000592:standards; D006801:Humans; D008403:Mass Screening / Q000592:standards*; D009361:Neoplasm Invasiveness / Q000175:diagnosis*; D009367:Neoplasm Staging; D009369:Neoplasms / Q000175:diagnosis / Q000401:mortality* / Q000473:pathology; D009517:New South Wales; D040442:Public Health Informatics / Q000592:standards; D012042:Registries / Q000592:standards*; D016019:Survival Analysis