title: Validation of a large basal cell carcinoma registry.
abstract: BACKGROUND
  The epidemiological study of basal cell carcinomas (BCCs) is difficult because BCCs lack distinct disease codes and are excluded from most cancer registries.
  
  
  OBJECTIVE
  To develop and validate a large BCC registry based on electronically assigned Systematized Nomenclature of Medicine (SNOMED) codes and text-string searches of electronic pathology reports from Kaiser Permanente Northern California.
  
  
  METHODS
  Potential BCCs were identified from electronic pathology reports (n=39,026) in 2005 and were reviewed by a dermatologist who assigned case/non-case status (gold-standard). A subset of the records (n=9,428) was independently reviewed by a second dermatologist to ascertain reliability of case assignment. In addition, a subset of excluded electronic pathology reports from 2005 (n=2,700) was reviewed to determine whether inclusion criteria had missed potential BCCs. We calculated the positive predictive value (PPV) of 3 different algorithms for identifying BCCs from electronic pathology data.
  
  
  RESULTS
  BCC-specific SNOMED codes had the highest PPV for identifying BCCs, 0.992 (95 percent CI: 0.991-0.993). Inter-rater reliability for case assignment was high (kappa=0.92, 95 percent CI: 0.91-0.93). Standardized incidence rates were consistent with previously published rates in the United States.
  
  
  CONCLUSIONS
  We created and validated a large BCC registry to serve as a unique resource for studying BCCs.
authors.forename: Maryam M
authors.initials: MM
authors.lastname: Asgari
authors.forename: Melody J
authors.initials: MJ
authors.lastname: Eide
authors.forename: E Margaret
authors.initials: EM
authors.lastname: Warton
authors.forename: Suzanne W
authors.initials: SW
authors.lastname: Fletcher
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002140:California / Q000453:epidemiology; D002280:Basal Cell Carcinoma / Q000453:epidemiology*; D018287:Carcinoma, Large Cell / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012042:Registries / Q000592:standards*; D017678:Sex Distribution; D012878:Skin Neoplasms / Q000453:epidemiology*; D039061:Systematized Nomenclature of Medicine; D055815:Young Adult