title: [Basal cell carcinoma: often more than one].
abstract: OBJECTIVE
  To calculate the cumulative risks and incidence rates for the development of multiple (two or more) basal cell carcinomas (BCC).
  
  
  METHODS
  A retrospective cohort study with data from PALGA, the nationwide network and registry of histopathology and cytopathology in the Netherlands.
  
  
  METHODS
  Using pathology reports, the first 2483 patients diagnosed with a first histologically confirmed BCC in the year 2004 were retrospectively followed for 5 years. The Andersen-Gill survival analysis was used to study whether gender or age affected the risk of developing multiple BCCs.
  
  
  RESULTS
  In total, 2483 patients developed 3793 BCCs. The five-year cumulative risk of developing multiple BCCs was 29.2%. The incidence rate for the development of two or more BCCs was 25,318 per 100,000 person-years in the first half year after first BCC diagnosis, decreasing to 6953 per 100,000 person-years after 5 years of follow-up. Compared with women men had a 30% (adjusted HR 1.30; 95% CI 1.11-1.53) higher risk of developing multiple BCCs and those aged 65-79 years had an 80% (adjusted HR 1.81; 95% CI 1.37-2.41) higher risk of having two or more BCCs compared with patients younger than 50 years.
  
  
  CONCLUSIONS
  Almost one third of the patients with a BCC developed two or more BCCs, most frequently in the period shortly after the first BCC. At diagnosis of BCC a full body skin examination should be performed and repeated annually for at least three years.
authors: Erasmus MC Universitair Medisch Centrum, Rotterdam, Afd. Dermatologie, the Netherlands.
authors: Sophie C
authors: SC
authors: Flohil
authors: Senada
authors: S
authors: Koljenović
authors: Ellen R M
authors: ER
authors: de Haas
authors: Lucia I H
authors: LI
authors: Overbeek
authors: Esther
authors: E
authors: de Vries
authors: Tamar
authors: T
authors: Nijsten
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002280:Basal Cell Carcinoma / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D012042:Registries; D012189:Retrospective Studies; D012306:Risk; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D016019:Survival Analysis