title: Cervical cancer and use of hormonal contraceptives: a systematic review.
abstract: BACKGROUND
  Human papillomavirus (HPV) is believed to be the most important cause of cervical cancer. Recent studies suggest that long duration use of oral contraceptives increases the risk of cervical cancer in HPV positive women.
  
  
  METHODS
  Results from published studies were combined to examine the relationship between invasive and in situ cervical cancer and duration and recency of use of hormonal contraceptives, with particular attention to HPV infection.
  
  
  RESULTS
  28 eligible studies were identified, together including 12531 women with cervical cancer. Compared with never users of oral contraceptives, the relative risks of cervical cancer increased with increasing duration of use: for durations of approximately less than 5 years, 5-9 years, and 10 or more years, respectively, the summary relative risks were 1.1 (95% CI 1.1-1.2), 1.6 (1.4-1.7), and 2.2 (1.9-2.4) for all women; and 0.9 (0.7-1.2), 1.3 (1.0-1.9), and 2.5 (1.6-3.9) for HPV positive women. The results were broadly similar for invasive and in situ cervical cancers, for squamous cell and adenocarcinoma, and in studies that adjusted for HPV status, number of sexual partners, cervical screening, smoking, or use of barrier contraceptives. The limited available data suggest that the relative risk of cervical cancer may decrease after use of oral contraceptives ceases. However, study designs varied and there was some heterogeneity between study results.
  
  
  CONCLUSIONS
  Although long duration use of hormonal contraceptives is associated with an increased risk of cervical cancer, the public health implications of these findings depend largely on the extent to which the observed associations remain long after use of hormonal contraceptives has ceased, and this cannot be evaluated properly from published data.
authors.affiliation: International Agency for Research on Cancer, Lyon, France.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Smith
authors.forename: Jane
authors.initials: J
authors.lastname: Green
authors.forename: Amy
authors.initials: A
authors.lastname: Berrington de Gonzalez
authors.forename: Paul
authors.initials: P
authors.lastname: Appleby
authors.forename: Julian
authors.initials: J
authors.lastname: Peto
authors.forename: Martyn
authors.initials: M
authors.lastname: Plummer
authors.forename: Silvia
authors.initials: S
authors.lastname: Franceschi
authors.forename: Valerie
authors.initials: V
authors.lastname: Beral
mesh_terms: D016022:Case-Control Studies; D003278:Contraceptives, Oral, Hormonal / Q000009:adverse effects*; D005260:Female; D006801:Humans; D030361:Papillomavirus Infections / Q000150:complications*; D012306:Risk; D002583:Uterine Cervical Neoplasms / Q000139:chemically induced / Q000209:etiology
chemical_list: D003278:Contraceptives, Oral, Hormonal