title: The incidence of metastatic basal cell carcinoma (mBCC) in Denmark, 1997-2010.
abstract: BACKGROUND
  Few data exist on the occurrence of metastatic basal cell carcinoma (mBCC).
  
  
  OBJECTIVE
  To identify all cases of mBCC in Denmark over a 14-year period.
  
  
  METHODS
  We searched the Danish National Patient Registry covering all Danish hospitals, the Danish Cancer Registry, the National Pathology Registry and the Causes of Death Registry during the period 1997 to 2010 for potential cases of mBCC registered according to the International classification of diseases ICD-10 and the International Systemized Nomenclature of Medicine (SNOMED).
  
  
  RESULTS
  We identified 126,627 patients with a history of primary basal cell carcinoma (BCC) in the registries during the 14-year study period. Using case identifications from the four registries, a total of 170 potential mBCC cases were identified. However, after a pathology review, only five cases could be confirmed, of which three were basosquamous carcinomas. The 14-year cumulative incidence proportion of mBCC was 0.0039% (95% CI 0.0016-0.0083) among individuals with a history of previous BCC (n = 126,627) and 0.0001% (95% CI 0.0000-0.0002) in the general population.
  
  
  CONCLUSIONS
  MBCC is a rare disease and only a small proportion of potential cases identified in automated clinical databases or registries can be confirmed by pathology and medical record review.
authors.affiliation: Department of Clinical Epidemiology.
authors.forename: Mary
authors.initials: M
authors.lastname: Nguyen-Nielsen
authors.affiliation: Genentech, South San Francisco, CA, USA.
authors.forename: Lisa
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Clinical Epidemiology.
authors.forename: Lars
authors.initials: L
authors.lastname: Pedersen
authors.affiliation: Department of Dermatology.
authors.forename: Anne Braae
authors.initials: AB
authors.lastname: Olesen
authors.affiliation: Genentech, South San Francisco, CA, USA.
authors.forename: Jeannie
authors.initials: J
authors.lastname: Hou
authors.affiliation: Genentech, South San Francisco, CA, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Mackey
authors.affiliation: Genentech, South San Francisco, CA, USA.
authors.forename: Margaret
authors.initials: M
authors.lastname: McCusker
authors.affiliation: Service de dermatologie, Hôpital Saint-Louis, Paris, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Basset-Seguin
authors.affiliation: Department of Clinical Epidemiology,, EpidStat Institute, Ann Arbor, MI, USA.
authors.forename: Jon
authors.initials: J
authors.lastname: Fryzek
authors.affiliation: Institute of Pathology, Aalborg University Hospital, 9000Aalborg C, Denmark.
authors.forename: Mogens
authors.initials: M
authors.lastname: Vyberg
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D002280:Basal Cell Carcinoma / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009362:Neoplasm Metastasis / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D012042:Registries; D015203:Reproducibility of Results; D012189:Retrospective Studies; D017678:Sex Distribution; D012878:Skin Neoplasms / Q000453:epidemiology* / Q000473:pathology* / Q000628:therapy; D016019:Survival Analysis
keywords: basal cell carcinoma; epidemiology; incidence; metastases