title: Breast cancer and ductal carcinoma in situ among women with prior squamous or glandular precancer in the cervix: a register-based study.
abstract: BACKGROUND
  Human papillomavirus and hormonal contraceptives may be risk factors for cervical precancer and malignant breast tumours.
  
  
  METHODS
  Standardised incidence ratios (SIRs) of malignant breast tumours during 1970-2008 were estimated separately for women with prior squamous and glandular cervical precancer.
  
  
  RESULTS
  Women with squamous precancer and women with glandular precancer in the cervix had a significantly higher risk of malignant breast tumours than the general female population (SIR, 95% confidence interval: 1.10, 1.05-1.14 and 1.52, 1.11-2.08, respectively).
  
  
  CONCLUSIONS
  Shared risk factors or screening attendance may explain the excess risk of malignant breast tumours among women with a history of cervical precancer.
authors.affiliation: Department of Research, Cancer Registry of Norway, PO Box 5313 Majorstuen, Oslo 0304, Norway. bo.terning.hansen@kreftregisteret.no
authors.forename: B T
authors.initials: BT
authors.lastname: Hansen
authors.forename: M
authors.initials: M
authors.lastname: Nygård
authors.forename: R S
authors.initials: RS
authors.lastname: Falk
authors.forename: S
authors.initials: S
authors.lastname: Hofvind
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology*; D002278:Carcinoma in Situ / Q000453:epidemiology*; D002294:Carcinoma, Squamous Cell / Q000453:epidemiology*; D002584:Cervix Uteri / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011230:Precancerous Conditions / Q000453:epidemiology; D012042:Registries; D012307:Risk Factors; D002583:Uterine Cervical Neoplasms / Q000453:epidemiology*