Oral contraceptive and reproductive risk factors for ovarian cancer within sisters in the breast cancer family registry |
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Authors: | J S Ferris M B Daly S S Buys J M Genkinger Y Liao M B Terry |
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Institution: | 1.Department of Epidemiology, Columbia University, Mailman School of Public Health, New York, NY 10032, USA;2.Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111-2497, USA;3.Huntsman Cancer Institute, University of Utah Health Sciences Center, Salt Lake City, UT 84112, USA;4.Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY 10032, USA |
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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. |
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Keywords: | oral contraceptives parity breastfeeding ovarian cancer family sisters high risk BRCA1/2 |
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