Oral Contraceptive and Reproductive Risk Factors for Ovarian Cancer Within Sisters in the Breast Cancer Family Registry

Br J Cancer. 2014 Feb 18;110(4):1074-80. doi: 10.1038/bjc.2013.803. Epub 2014 Jan 7.

Abstract

Background: Oral contraceptive use has been consistently associated with a reduced risk of ovarian cancer in unrelated, average risk women; however little data exist on whether this benefit extends to higher risk women from cancer families. To examine this, we conducted family-based analyses using the Breast Cancer Family Registry.

Methods: We used generalised estimating equations to obtain the population average effect across all families (n=389 cases, n=5643 controls) and conditional logistic regression to examine within-family differences in a subset with at least two sisters discordant on ovarian cancer status (n=109 cases, n=149 unaffected sister controls).

Results: In the multivariable generalised estimating equation model there was a reduced risk of ovarian cancer for ever use of oral contraceptives compared with never use (OR=0.58, 95% CI: 0.37, 0.91), and in the conditional logistic model there was a similar inverse association; however, it was not statistically significant (OR=0.52, 95% CI: 0.23, 1.17). We examined this association by BRCA1/2 status and observed a statistically significant reduced risk in the non-carriers only.

Conclusion: We observed a decreased risk of ovarian cancer with oral contraceptive use supporting that this association observed in unrelated women extends to related women at higher risk.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • BRCA1 Protein / genetics
  • BRCA2 Protein / genetics
  • Breast Neoplasms / epidemiology*
  • Breast Neoplasms / genetics
  • Contraceptives, Oral / adverse effects*
  • Female
  • Humans
  • Middle Aged
  • Ovarian Neoplasms / epidemiology*
  • Ovarian Neoplasms / genetics
  • Risk
  • Risk Assessment
  • Risk Factors
  • Siblings
  • Surveys and Questionnaires

Substances

  • BRCA1 Protein
  • BRCA1 protein, human
  • BRCA2 Protein
  • BRCA2 protein, human
  • Contraceptives, Oral