Hereditary breast cancer treatment
Hereditary breast cancer may differ from sporadic breast cancer in ways that could effect treatment options. Therefore genetic counseling and testing are often recommended soon after breast cancer diagnosis if it is believed that the results may effect treatment decisions.
Some possible treatment decisions that may be influenced by genetic test results include:
- lumpectomy and radiation vs. mastectomy
- Research has shown that, under certain circumstances, lumpectomy followed by radiation is as effective as mastectomy for treating breast cancer. In women with BRCA mutations or hereditary breast cancer, however, there is an elevated risk for a second primary cancer in the same or the opposite breast. Because of this risk for a second cancer, some women who are diagnosed with hereditary breast cancer choose bilateral mastectomy (surgical removal of both breasts) rather than undergoing lumpectomy and radiation. Studies have shown similar survival rates for women with BRCA mutations who undergo lumpectomy and radiation and women who undergo mastectomy. However, mutation carriers who undergo mastectomy are less likely to develop a second breast cancer.
- oophorectomy vs. medication to induce menopause
- Some women with hereditary breast cancer are at increased risk for ovarian cancer due to mutations in BRCA, BRIP1, RAD51C, RAD51D or family history of ovarian cancer. In women with estrogen receptor-positive breast cancer, treatment often involves injections to shut down the ovaries' production of estrogen. For women who are at increased risk for ovarian cancer, another option may be oophorectomy, which removes the ovaries to lower the risk for ovarian cancer. Further, oophorectomy has also been shown to lower the risk for primary breast cancers in BRCA carriers who do not have bilateral mastectomies. One very small observational study showed a lower recurrence rate in BRCA 1 mutation carriers who had oophorectomy within 6 months of their breast cancer diagnosis compared with those who retained their ovaries. Another study showed that a quarter of early stage breast cancer survivors with a BRCA mutation later develop ovarian cancer if they do not remove their ovaries.
- Tamoxifen, aromatase inhibitors or other hormonal therapies
- Tamoxifen is a treatment used for estrogen receptor-positive breast cancer. Studies of BRCA carriers who were diagnosed with cancer in one breast and took tamoxifen demonstrated a reduced risk for breast cancer in the other breast. One such study showed tamoxifen lowered the risk for a new breast cancer in the other breast by about 40% in women with BRCA 1 mutations and by about 25% in women with BRCA 2 mutations. Tamoxifen may also protect bone density and reduce osteoporosis risk in postmenopausal women who cannot take hormone replacement. Not all experts agree that tamoxifen is appropriate for preventing a second breast cancer in women with BRCA1 mutations. For more information, see our section on tamoxifen.
- Aromatase inhibitors are medications that are prescribed for some post-menopausal women to reduce estrogen production by their fat cells and adrenal cells. These drugs are used for preventing breast cancer recurrence in women with cancers that are estrogen or hormone-receptor positive. One study found that an aromatase inhibitor known as anastrozole reduced breast cancer survivors' risk developing a new cancer in the other breast by 58 percent. This study did not look specifically at women with BRCA mutations, so the benefits of these medications to prevent breast cancer in BRCA carriers is not certain. For more information, see our section on aromatase inhibitors.
As new research continues, treatments specifically targeting hereditary cancers may become available. Some studies have suggested that BRCA-associated cancers may respond more favorably to certain chemotherapies. Other research suggests that people diagnosed with triple negative breast cancer who have a BRCA mutation may respond particularly well to platinum chemotherapy.
A new class of medications called "PARP Inhibitors" may specifically kill cancer cells with mutations in BRCA or other genes involved hereditary cancer and spare healthy cells. Two PARP inhibitors, Lynparza and Rubraca, are approved for treatment of some advanced ovarian cancer. Several large clinical trials are looking at using PARP inhibitors to treat hereditary breast cancer. See our clinical trials page for information on PARP inhibitor studies.