The well-known risk of breast cancer for women who harbor mutations in the BRCA1 gene is significantly reduced among those who have breast-fed for a cumulative total of more than 12 months, new research shows.

The protective effects of breast-feeding seem to be much greater for BRCA1 mutation carriers than for women in general population.

“This means that if the woman is identified to have a BRCA1 mutation, it is possible to modify her breast cancer risk without having to resort to surgery,” Dr. Steven A. Narod from the Centre for Research in Women’s Health in Toronto told Reuters Health.

Narod’s team evaluated of 965 women with breast cancer and an equal number of control women without breast or ovarian cancer. Among the 685 women with BRCA1 mutations, the average total duration of breast-feeding was significantly shorter for those who developed cancer than for those who did not.

Women carrying BRCA1 mutations who breast-fed for more than 1 year were about 60 percent less likely to have breast cancer than women who never breast-fed, the investigators report in the Journal of the National Cancer Institute.

Nonetheless, “the remaining risk is still high,” Narod commented.

“We are making a lot of progress in identifying the means of reducing breast and ovarian cancer risk in BRCA1 mutation carriers,” Narod continued. “And this means that it will become more acceptable to undergo genetic testing,” he added.

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