No one knows very much about why breast cancer happens, except that it likely starts in our genes. "Cancer in general is a disease of aging, and breast cancer is probably caused by an error in gene replicationthe older we get, the more error prone we get," says Ramona F. Swaby, MD, a medical oncologist specializing in breast cancer at Fox Chase Cancer Center in Philadelphia. Indeed, a womans chance of getting breast cancer doesnt rise to the terrifying one in eight until shes reached 85 years of age. If youre a woman under 40, for instance, your risk is much lower: one in 233.
If youre wondering whether you carry the BRCA-1 or BRCA-2 mutations, you may have considered getting a genetic test to find out. Thats a tough decision, because its not always clear what to do with your test results. Some women who know they are at higher risk without taking the test simply commit to more frequent mammograms; others feel the need to know as much as possible and may consider prophylactic surgery if they test positive.