Breast feeding for a cumulative total of more than 1 year is associated with a reduced risk of breast cancer in BRCA1 mutation carriers, according to a new study published in the Journal of the National Cancer Institute.

Previous studies of the general population have shown that the risk of breast cancer is reduced in women who breast-feed their children.

In a case-control study, Steven A. Narod, M.D., of the Centre for Research in Women's Health in Toronto, and colleagues examined the association between breast cancer risk and breast-feeding among women with deleterious BRCA mutations.

They found that, among women with BRCA1 mutations, the total duration of breast-feeding was associated with a reduced risk of breast cancer. Women with BRCA1 mutations who breast-fed for more than 1 year in total during their lifetime were less likely to have breast cancer than those who never breast-fed, although no such association was seen for women with BRCA2 mutations.

SOURCE:
Journal of the National Cancer Institute, July 21, 2004