Wikipedia has a good summary of the risks: http://en.wikipedia.org/wiki/BRCA_mutation http://en.wikipedia.org/wiki/BRCA_mutation A 25-year-old woman with no m

Wikipedia has a good summary of the risks: http://en.wikipedia.org/wiki/BRCA_mutation http://en.wikipedia.org/wiki/BRCA_mutation A 25-year-old woman with no mutation in her BRCA genes has an 84% probability to reach at least the age of 70.[16] Of those not surviving, 11% die from either breast or ovarian cancer, and 89% from other causes. Compared to that, a woman with a high-risk BRCA1 mutation, if she had breast cancer screening but no prophylactic medical or surgical intervention, would have only 59% chance to reach age 70, twenty-five percentage points lower than normal. Of those women not surviving, 26% would die of breast cancer, 46% ovarian cancer, and 28% other causes.[16] Women with high-risk BRCA2 mutations, with screening but with no prophylactic medical or surgical intervention, would have only 75% chance to reach age 70, nine percentage points lower than normal. Of those not surviving, 21% would die of breast cancer, 25% ovarian cancer and 54% other causes.[16] The likelihood of surviving to at least age 70 can be improved by several medical interventions, notably prophylactic mastectomy and oophorectomy.[16]