Breast Cancer: Prevention...

If you are considered a high risk for breast cancer there are some recommendations that your doctor may make to limit your risk:

Removal of the Ovaries

Prophylactic oophorectomy (removal of ovaries), in high-risk individuals, when child-bearing is complete, reduces the risk of developing breast cancer by 60%, as well as reducing the risk of developing ovarian cancer by 96%.
Managing side effects of prophylactic oophorectomy
Non-hormonal treatments
The side effects of Oophorectomy may be alleviated by medicines other than hormonal replacement. Non-hormonal biphosphonates (such as Fosamax and Actonel) increase bone strength and are available as once-a-week pills. Low-dose Selective Serotonin Reuptake Inhibitors (e.g. Paxil, Prozac) alleviate so called "hot flashes".
Hormonal treatments
Short-term hormone replacement with estrogen, was not shown to increase the risk of breast cancer in women who are post-oophorectomy. This result can probably be generalized to other women at high risk, in whom short term (i.e., one or two year) treatment with estrogen for hot flashes, may be acceptable.

Prophylactic mastectomy

Bilateral prophylactic mastectomies have been shown to prevent breast cancer in high-risk individuals.

Medications

Hormonal therapy has been used for chemoprevention in individuals at high risk for breast cancer. In 2002, a clinical practice guideline by the U.S. Preventive Services Task Force (USPSTF) recommended "clinicians discuss chemoprevention with women at high risk for breast cancer and at low risk for adverse effects of chemoprevention" with a grade B recommendation.