Losing weight in young adult life can reduce the risk of early-onset breast cancers associated with BRCA1/2 mutations, according to a multicenter study. "Breast cancer prevention starts early in life," Dr. Steven A. Narod told Reuters Health. "Probably this is a critical period for the hormones involved to be interacting with the breast tissue."
Narod, from the University of Toronto, Ontario, Canada, and colleagues investigated whether changes in body weight were associated with the risk of breast cancer in 1,073 women who carried BRCA1 or BRCA2 mutations.
Weight loss of at least 10 pounds between age 18 and 30 was associated with a 33-percent reduction in the risk of breast cancer thereafter, the researchers report in the Breast Cancer Research, whereas weight gain was not associated with a change in risk.
This reduction in risk was mainly seen for cancers occurring between the ages of 30 and 40, the report indicates.
The risk reduction appeared to be greater among women with a BRCA1 mutation (65-percent risk reduction) than among women with a BRCA2 mutation (12-percent risk reduction), the researchers note.
A weight gain greater than 10 pounds among women who had at least two full-term pregnancies was associated with a 44 percent increased risk of breast cancer, the investigators found.
"Our findings suggest that weight loss in early adult life (and not weight per se) decreases the risk of BRCA-associated breast cancer diagnosed at an early age," the authors conclude. "More specifically, the period between age 18 and 30 years appears to be a critical one when weight gain should be avoided in mutation carriers."
"We are doing a prospective study looking at new cases of breast cancer which arise among healthy women to confirm and extend these findings," Narod added.
SOURCE: Breast Cancer Research, August 19, 2005.
