Abstract
IntroductionBreastfeeding has been inversely related to breast cancer risk in the general population. Clarifying the role of breastfeeding among women with a BRCA1 or BRCA2 mutation may be helpful for risk assessment and for recommendations regarding prevention. We present an updated analysis of breastfeeding and risk of breast cancer using a large matched sample of BRCA mutation carriers.MethodsWe conducted a case-control study of 1,665 pairs of women with a deleterious mutation in either BRCA1 (n = 1,243 pairs) or BRCA2 (n = 422 pairs). Breast cancer cases and unaffected controls were matched on year of birth, mutation status, country of residence and parity. Information about reproductive factors, including breastfeeding for each live birth, was collected from a routinely administered questionnaire. Conditional logistic regression was used to estimate the association between ever having breastfed, as well as total duration of breastfeeding, and the risk of breast cancer.ResultsAmong BRCA1 mutation carriers, breastfeeding for at least one year was associated with a 32% reduction in risk (OR = 0.68; 95% CI 0.52 to 0.91; P = 0.008); breastfeeding for two or more years conferred a greater reduction in risk (OR = 0.51; 95% CI 0.35 to 0.74). Among BRCA2 mutation carriers, there was no significant association between breastfeeding for at least one year and breast cancer risk (OR = 0.83; 95% CI 0.53 to 1.31; P = 0.43).ConclusionsThese data extend our previous findings that breastfeeding protects against BRCA1-, but not BRCA2-associated breast cancer. BRCA mutation carriers should be advised of the benefit of breastfeeding in terms of reducing breast cancer risk.
Highlights
Breastfeeding has been inversely related to breast cancer risk in the general population
We have previously reported in a study of 965 matched pairs that the total duration of breastfeeding was associated with a significant reduction in breast cancer risk among breast cancer susceptibility gene 1 (BRCA1), but not among breast cancer susceptibility gene 2 (BRCA2), mutation carriers [11]
Hormone replacement therapy (HRT) use was significantly lower in both BRCA1 and BRCA2 cases versus controls (5% vs. 12%; P < 0.0001 and 10.7% vs. 16.5%; P = 0.02, respectively)
Summary
Breastfeeding has been inversely related to breast cancer risk in the general population. We present an updated analysis of breastfeeding and risk of breast cancer using a large matched sample of BRCA mutation carriers. Reproductive factors, including late age at menarche, parity and breastfeeding, have been shown to protect against the development of breast cancer [1,2,3]. We have previously reported in a study of 965 matched pairs that the total duration of breastfeeding was associated with a significant reduction in breast cancer risk among BRCA1, but not among BRCA2, mutation carriers [11]. We update the analysis of total duration of breastfeeding and risk of breast cancer using a larger sample of BRCA mutation carriers with the addition of 700 matched pairs. Because childbirth and breastfeeding are strongly correlated, we restricted the present analysis to parous women and we matched on parity to eliminate any potential confounding effect of parity
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
