Objective: To determine whether oral contraceptive (OC) use, childbearing, breastfeeding and tubal ligation differ between ovarian cancer cases with and without a BRCA1/2 mutation.
Methods: A case-only study of 242 Jewish women with invasive epithelial ovarian cancer. Women were genotyped for three Ashkenazi founder mutations (185delAG and 5382insC in BRCA1 and 6174delT in BRCA2). We obtained data on OC use, childbearing, breastfeeding, gynecologic surgeries and other reproductive factors from each woman. We compared the frequencies of these risk factors in carriers and non-carriers using unconditional logistic-regression, controlling for other covariates.
Results: Among the 242 cases, 64 (26.4%) carried one of the BRCA1 founder mutations, and 31 (12.8%) carried the BRCA2 mutation. Although there were no differences in the percent of nulliparous women between carriers and non-carriers, parous BRCA1 carriers reported fewer live births than non-carriers (average of 2.1 versus 2.5 live births, OR = 0.61, 95% CI = 0.39-0.95, adjusted for age at diagnosis, tubal ligation and duration of OC use). Carriers and non-carriers did not differ in their history of breastfeeding, or in their lifetime use of OCs. BRCA1 carriers were more likely than non-carriers to have had a tubal ligation (25.0 versus 10.2%, OR = 3.67, 95% CI = 1.55-8.70, adjusted for age at diagnosis, number of live births and OC duration).
Conclusions: In general, OC use, childbearing and breastfeeding do not differ between BRCA1/2 carriers and non-carriers with ovarian cancer. However, the effects of tubal ligation may differ between BRCA1 carriers and non-carriers.