Cervical cancer and hormonal contraceptives: Collaborative reanalysis of individual data for 16 573 women with cervical cancer and 35 509 women without cervical cancer from 24 epidemiological studies

Research output: Contribution to journalArticle

Abstract

Background Combined oral contraceptives are classified by the International Agency for Research on Cancer as a cause of cervical cancer. As the incidence of cervical cancer increases with age, the public-health implications of this association depend largely on the persistence of effects long after use of oral contraceptives has ceased. Information from 24 studies worldwide is pooled here to investigate the association between cervical carcinoma and pattern of oral contraceptive use. Methods Individual data for 16 573 women with cervical cancer and 35 509 without cervical cancer were reanalysed centrally. Relative risks of cervical cancer were estimated by conditional logistic regression, stratifying by study, age, number of sexual partners, age at first intercourse, parity, smoking, and screening. Findings Among current users of oral contraceptives the risk of invasive cervical cancer increased with increasing duration of use (relative risk for 5 or more years' use versus never use, 1-90 [95% Cl 1-69-2-13]). The risk declined after use ceased, and by 10 or more years had returned to that of never users. A similar pattern of risk was seen both for invasive and in-situ cancer, and in women who tested positive for high-risk human papillornavirus. Relative risk did not vary substantially between women with different characteristics. Interpretation The relative risk of cervical cancer is increased in current users of oral contraceptives and declines after use ceases. 10 years' use of oral contraceptives from around age 20 to 30 years is estimated to increase the cumulative incidence of invasive cervical cancer by age 50 from 7.3 to 8.3 per 1000 in less developed countries and from 3.8 to 4.5 per 1000 in more developed countries.

Details

Authors
  • International Collaboration of Epidemiological Studies of Cervical Cancer
  • Paul Appleby
  • Valerie Beral
  • Amy Berrington de Gonzalez
  • Didier Colin
  • Silvia Franceschi
  • Adrian Goodhill
  • Jane Green
  • Julian Peto
  • Martyn Plummer
  • Sian Sweetland
  • Joakim Dillner
  • Ilvars Silins
  • et al
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Microbiology in the medical area
Original languageEnglish
Pages (from-to)1609-1621
JournalThe Lancet
Volume370
Issue number9599
Publication statusPublished - 2007
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

Collaborators from: Lund University, Malmo, Sweden: J Dillner, I Silins.