title: A family history of breast cancer will not predict female early onset breast cancer in a population-based setting.
abstract: BACKGROUND
  An increased risk of breast cancer for relatives of breast cancer patients has been demonstrated in many studies, and having a relative diagnosed with breast cancer at an early age is an indication for breast cancer screening. This indication has been derived from estimates based on data from cancer-prone families or from BRCA1/2 mutation families, and might be biased because BRCA1/2 mutations explain only a small proportion of the familial clustering of breast cancer. The aim of the current study was to determine the predictive value of a family history of cancer with regard to early onset of female breast cancer in a population based setting.
  
  
  METHODS
  An unselected sample of 1,987 women with and without breast cancer was studied with regard to the age of diagnosis of breast cancer.
  
  
  RESULTS
  The risk of early-onset breast cancer was increased when there were: (1) at least 2 cases of female breast cancer in first-degree relatives (yes/no; HR at age 30: 3.09; 95% CI: 128-7.44), (2) at least 2 cases of female breast cancer in first or second-degree relatives under the age of 50 (yes/no; HR at age 30: 3.36; 95% CI: 1.12-10.08), (3) at least 1 case of female breast cancer under the age of 40 in a first- or second-degree relative (yes/no; HR at age 30: 2.06; 95% CI: 0.83-5.12) and (4) any case of bilateral breast cancer (yes/no; HR at age 30: 3.47; 95%: 1.33-9.05). The positive predictive value of having 2 or more of these characteristics was 13% for breast cancer before the age of 70, 11% for breast cancer before the age of 50, and 1% for breast cancer before the age of 30.
  
  
  CONCLUSIONS
  Applying family history related criteria in an unselected population could result in the screening of many women who will not develop breast cancer at an early age.
authors.affiliation: Department of Epidemiology, Groningen University Medical Center, Groningen, The Netherlands. g.h.de.bock@epi.umcg.nl
authors.forename: Geertruida H
authors.initials: GH
authors.lastname: de Bock
authors.forename: Catharina E
authors.initials: CE
authors.lastname: Jacobi
authors.forename: Caroline
authors.initials: C
authors.lastname: Seynaeve
authors.forename: Elly M M
authors.initials: EM
authors.lastname: Krol-Warmerdam
authors.forename: Jannet
authors.initials: J
authors.lastname: Blom
authors.forename: Christi J
authors.initials: CJ
authors.lastname: van Asperen
authors.forename: Cees J
authors.initials: CJ
authors.lastname: Cornelisse
authors.forename: Jan G M
authors.initials: JG
authors.lastname: Klijn
authors.forename: Peter
authors.initials: P
authors.lastname: Devilee
authors.forename: Rob A E M
authors.initials: RA
authors.lastname: Tollenaar
authors.forename: Cecile T M
authors.initials: CT
authors.lastname: Brekelmans
authors.forename: Johannes C
authors.initials: JC
authors.lastname: van Houwelingen
mesh_terms: D000328:Adult; D017668:Age of Onset; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D005828:Genetics, Population; D006801:Humans; D008875:Middle Aged; D008957:Models, Genetic; D015999:Multivariate Analysis; D009154:Mutation; D011237:Predictive Value of Tests; D012306:Risk