Your test for a BRCA gene mutation has come back positive —what now? Here are some options available to you for early identification or prevention of cancers associated with BRCA mutations:

• Intensive surveillance for early evidence of breast cancer
• Chemoprevention to try to reduce the risk of, or to delay the development of breast cancer
• Prophylactic bilateral mastectomy (the surgical removal of both breasts before the formation of cancerous cells)
• Surgical removal of ovaries and Fallopian tubes

Frequent surveillance.
The American Cancer Society recommends frequent surveillance with both conventional mammography and with MRI screening. If you have a BRCA mutation, you should start getting an annual mammogram at about age 25. And, although MRI screening is more expensive than regular mammography ($1,000 to $2,000 for MRI compared with $100 to $200 for mammography), an MRI is more sensitive, especially in women with dense breasts.

It is more difficult to identify early ovarian cancer. Possible screening tests include annual or semiannual transvaginal ultrasound, as well as blood tests for detecting CA-125 levels. (CA-125 is a protein present in higher-than-normal amounts in the blood and urine of patients with certain cancers.) These tests should start before age 35.

Chemoprevention.
Some studies have shown that chemoprevention treatment with estrogen-like agents, tamoxifen or possibly raloxifene, reduced the risk of developing breast cancer in women with BRCA mutations. These findings are somewhat surprising because BRCA1 mutations are generally associated with estrogen-negative breast cancers (cancers whose growth is not affected by estrogen and that usually don't respond to the administration of tamoxifen or raloxifene). Some studies have shown a reduction of ovarian cancer by as much as 60 percent when women with BRCA mutations use oral contraceptives.

Bilateral mastectomy.
Prophylactic removal of both breasts is unappealing, but is about 90 percent effective in preventing breast cancer in women at high risk. Because identification of cancer in one breast is associated with a high likelihood (at least 30 percent) of cancer in the other breast, removal of the apparently normal breast or treatment with tamoxifen should be considered.

Surgical removal of ovaries and Fallopian tubes. Prophylactic removal of both ovaries and Fallopian tubes lowers the risk of cancers at these sites by nearly 100 percent. Since ovarian cancer occurs later than breast cancer, such surgical procedures can be delayed until age 35, or after childbearing is completed. For reasons that are unclear, removal of both ovaries before menopause also halves the risk of breast cancer.