title: Diagnostic chest X-rays and breast cancer risk before age 50 years for BRCA1 and BRCA2 mutation carriers.
abstract: BACKGROUND
  The effects of low-dose medical radiation on breast cancer risk are uncertain, and few studies have included genetically susceptible women, such as those who carry germline BRCA1 and BRCA2 mutations.
  
  
  METHODS
  We studied 454 BRCA1 and 273 BRCA2 mutation carriers ages younger than 50 years from three breast cancer family registries in the United States, Canada, and Australia/New Zealand. We estimated breast cancer risk associated with diagnostic chest X-rays by comparing mutation carriers with breast cancer (cases) with those without breast cancer (controls). Exposure to chest X-rays was self-reported. Mammograms were not considered in the analysis.
  
  
  RESULTS
  After adjusting for known risk factors for breast cancer, the ORs for a history of diagnostic chest X-rays, excluding those for tuberculosis or pneumonia, were 1.16 [95% confidence interval (CI), 0.64-2.11] for BRCA1 mutations carriers and 1.22 (95% CI, 0.62-2.42) for BRCA2 mutations carriers. The OR was statistically elevated for BRCA2 mutation carriers with three to five diagnostic chest X-rays (P = 0.01) but not for those with six or more chest X-rays. Few women reported chest fluoroscopy for tuberculosis or chest X-rays for pneumonia; the OR estimates were elevated, but not statistically significant, for BRCA1 mutation carriers.
  
  
  CONCLUSIONS
  Our findings do not support a positive association between diagnostic chest X-rays and breast cancer risk before the ages of 50 years for BRCA1 or BRCA2 mutation carriers.
  
  
  CONCLUSIONS
  Given the increasing use of diagnostic imaging involving higher ionizing radiation doses, further studies of genetically predisposed women are warranted.
authors.affiliation: Cancer Prevention Institute of California, 2201 Walnut Avenue, Suite 300, Fremont, CA 94538-2334, USA. esther.john@cpic.org
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.forename: Valerie
authors.initials: V
authors.lastname: McGuire
authors.forename: Duncan
authors.initials: D
authors.lastname: Thomas
authors.forename: Robert
authors.initials: R
authors.lastname: Haile
authors.forename: Hilmi
authors.initials: H
authors.lastname: Ozcelik
authors.forename: Roger L
authors.initials: RL
authors.lastname: Milne
authors.forename: Anna
authors.initials: A
authors.lastname: Felberg
authors.forename: Dee W
authors.initials: DW
authors.lastname: West
authors.forename: Alexander
authors.initials: A
authors.lastname: Miron
authors.forename: Julia A
authors.initials: JA
authors.lastname: Knight
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Terry
authors.forename: Mary
authors.initials: M
authors.lastname: Daly
authors.forename: Saundra S
authors.initials: SS
authors.lastname: Buys
authors.forename: Irene L
authors.initials: IL
authors.lastname: Andrulis
authors.forename: John L
authors.initials: JL
authors.lastname: Hopper
authors.forename: Melissa C
authors.initials: MC
authors.lastname: Southey
authors.forename: Graham G
authors.initials: GG
authors.lastname: Giles
authors.forename: Carmel
authors.initials: C
authors.lastname: Apicella
authors.forename: Heather
authors.initials: H
authors.lastname: Thorne
authors.forename: Alice S
authors.initials: AS
authors.lastname: Whittemore
mesh_terms: D000328:Adult; D001315:Australia / Q000453:epidemiology; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000235:genetics*; D002170:Canada / Q000453:epidemiology; D003955:Diagnostic Tests, Routine; D005260:Female; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D020022:Genetic Predisposition to Disease; D006801:Humans; D008875:Middle Aged; D009154:Mutation; D009520:New Zealand / Q000453:epidemiology; D013902:Radiography, Thoracic / Q000706:statistics & numerical data*; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology