BACKGROUND: Multiparity and breast-feeding reduce breast cancer risk, whereas oral contraceptive use may slightly increase breast cancer risk in the general population. However, the effects of these factors in BRCA1 and BRCA2 mutation carriers are less clear. METHODS: Case patients were 1,469 women from Los Angeles County ages 20 to 49 years with newly diagnosed breast cancer. Control subjects were 444 women without breast cancer, individually matched to a subset of cases on race, age, and neighborhood. BRCA1/2 genes were sequenced in the cases, and odds ratios of breast cancer associated with various reproductive and hormonal factors in BRCA1/2 mutation carriers and noncarriers were estimated using multivariable logistic regression. RESULTS: Ninety-four women had a deleterious BRCA1 or BRCA2 mutation. Number of full-term pregnancies was inversely associated with breast cancer risk regardless of BRCA1/2 mutation status. Longer breast-feeding duration was protective among noncarriers but not among mutation carriers; however, this apparent effect modification was not statistically significant (P = 0.23). Neither oral contraceptive use overall nor the use of low-dose oral contraceptives was associated with an increased risk of breast cancer in any subgroup. CONCLUSIONS: Our results suggest that parity protects against breast cancer in BRCA1/2 mutation carriers, whereas breast-feeding does not. Our data suggest no association between oral contraceptive use and breast cancer risk in BRCA1/2 mutation carriers. Further confirmation that currently available low-dose oral contraceptives do not increase breast cancer risk in carriers is important from a public health perspective given the high prevalence of oral contraceptive use in the United States.
BACKGROUND: Multiparity and breast-feeding reduce breast cancer risk, whereas oral contraceptive use may slightly increase breast cancer risk in the general population. However, the effects of these factors in BRCA1 and BRCA2 mutation carriers are less clear. METHODS: Case patients were 1,469 women from Los Angeles County ages 20 to 49 years with newly diagnosed breast cancer. Control subjects were 444 women without breast cancer, individually matched to a subset of cases on race, age, and neighborhood. BRCA1/2 genes were sequenced in the cases, and odds ratios of breast cancer associated with various reproductive and hormonal factors in BRCA1/2 mutation carriers and noncarriers were estimated using multivariable logistic regression. RESULTS: Ninety-four women had a deleterious BRCA1 or BRCA2 mutation. Number of full-term pregnancies was inversely associated with breast cancer risk regardless of BRCA1/2 mutation status. Longer breast-feeding duration was protective among noncarriers but not among mutation carriers; however, this apparent effect modification was not statistically significant (P = 0.23). Neither oral contraceptive use overall nor the use of low-dose oral contraceptives was associated with an increased risk of breast cancer in any subgroup. CONCLUSIONS: Our results suggest that parity protects against breast cancer in BRCA1/2 mutation carriers, whereas breast-feeding does not. Our data suggest no association between oral contraceptive use and breast cancer risk in BRCA1/2 mutation carriers. Further confirmation that currently available low-dose oral contraceptives do not increase breast cancer risk in carriers is important from a public health perspective given the high prevalence of oral contraceptive use in the United States.
Authors: Calvin C Willhite; Nataliya A Karyakina; Robert A Yokel; Nagarajkumar Yenugadhati; Thomas M Wisniewski; Ian M F Arnold; Franco Momoli; Daniel Krewski Journal: Crit Rev Toxicol Date: 2014-10 Impact factor: 5.635
Authors: Mohammad R Motie; Sima Besharat; Reza Torkjazi; Mahdieh Shojaa; Mahsa Besharat; Abbasali Keshtkar; Gholamreza Roshandel; Saba Besharat; Arab Ameri Fateme Journal: Breast Care (Basel) Date: 2011-12-15 Impact factor: 2.860
Authors: Patricia G Moorman; Edwin S Iversen; P Kelly Marcom; Jeffrey R Marks; Frances Wang; Eunjung Lee; Giske Ursin; Timothy R Rebbeck; Susan M Domchek; Banu Arun; Lisa Susswein; Claudine Isaacs; Judy E Garber; Kala Visvanathan; Constance A Griffin; Rebecca Sutphen; Jennifer Brzosowicz; Stephen Gruber; Dianne M Finkelstein; Joellen M Schildkraut Journal: Breast Cancer Res Treat Date: 2010-03-23 Impact factor: 4.872