title: Conization as a marker of persistent cervical human papillomavirus (HPV) infection and risk of gastrointestinal cancer: a Danish 34-year nationwide cohort study.
abstract: OBJECTIVE
  Persistent cervical infection with human papillomavirus (HPV) may be a marker of poor immune function and thus associated with an increased cancer risk. HPV infection is implicated in all cases of cervical cancer, but except for anal and esophageal cancers, the association between persistent HPV infection and gastrointestinal cancer has not been investigated.
  
  
  METHODS
  We performed a nationwide population-based cohort study of 83,008 women undergoing cervical conization between 1978 and 2011, using cervical conization as a marker of chronic HPV infection. We computed standardized incidence ratios (SIRs) as a measure of the relative risk of each cancer comparing women undergoing conization with that expected in the general population. We also calculated absolute risks.
  
  
  RESULTS
  During follow-up, 988 GI cancers occurred versus 880 expected among 83,008 women followed for a median of 14.9 years, corresponding to a SIR of 1.1 (95 % CI 1.1-1.2). Risks were increased for anal (SIR 2.9; 95 % CI 2.3-3.5) and esophageal (SIR 1.5; 95 % CI 1.1-2.0) cancers, with suggested increased risks of cancers of the gallbladder and biliary tract (SIR 1.3; 95 % CI 0.90-1.8), pancreas (SIR 1.2; 95 % CI 0.97-1.4), and liver (SIR 1.1; 95 % CI 0.79-1.6). The SIRs decreased with increasing follow-up time. The risks of gastric, small intestinal, colon, or rectal cancers were not elevated. Overall, the absolute cancer risk was 0.18 % (95 % CI 0.15-0.21) after 5 years.
  
  
  CONCLUSIONS
  The relative risks of several gastrointestinal cancers were raised among women who underwent cervical conization for persistent HPV infection, but the absolute risks were low.
authors.affiliation: Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Allé 43-45, 8200, Aarhus N, Denmark.
authors.forename: Jakob
authors.initials: J
authors.lastname: Kirkegård
authors.forename: Dora Körmendiné
authors.initials: DK
authors.lastname: Farkas
authors.forename: Mette
authors.initials: M
authors.lastname: Søgaard
authors.forename: Sigrún Alba Jóhannesdóttir
authors.initials: SA
authors.lastname: Schmidt
authors.forename: Eva Bjerre
authors.initials: EB
authors.lastname: Ostenfeld
authors.forename: Deirdre
authors.initials: D
authors.lastname: Cronin-Fenton
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers; D015331:Cohort Studies; D019092:Conization / Q000706:statistics & numerical data*; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000175:diagnosis* / Q000473:pathology; D044382:Population Groups; D012306:Risk; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis* / Q000473:pathology; D016387:Women's Health; D055815:Young Adult; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000473:pathology
chemical_list: D015415:Biomarkers