According to an early online article in the Journal of Clinical Oncology, long-term follow-up indicates that breast cancer recurrences near the site of the original cancer are similar among women with BRCA1/2 mutations with early breast cancer who are treated with breast-conserving therapy, radiation therapy, and oophorectomy when compared to outcomes for other women following standard treatment. However, rates of breast cancer developing in the other breast remain significantly higher among women with BRCA1/2 mutations than other women.
Inherited mutations in two genes-BRCA1 and BRCA2-have been found to greatly increase the lifetime risk of developing breast and ovarian cancer. Alterations in these genes can be passed down through either the mother’s or the father’s side of the family.
Genetic testing for BRCA1 and BRCA2 mutations is often offered to women at high risk for carrying a gene mutation, but the currently available tests do not detect all types of mutations.
Women with BRCA1 and/or BRCA2 mutations often undergo frequent screening for breast and ovarian cancer so that the cancer is detected in its earliest and most treatable stages. A significant portion of women with these mutations also choose to undergo more radical preventive strategies, such as the removal of the ovaries (oophorectomy) or removal of the breasts (mastectomy), before cancer develops.
An oophorectomy not only significantly reduces the risk of developing ovarian cancer, but also reduces a woman’s risk of developing breast cancer. This is because the ovaries produce the hormone estrogen, which stimulates growth in the majority of breast cancers; these are referred to as hormone-positive or estrogen receptor-positive breast cancers.
Researchers from the U.S. and Canada recently evaluated data from long-term follow-up results among women with early breast cancer who were BRCA1/2 carriers; their results were compared to results from other women diagnosed with early breast cancer.
This study included 160 women with BRCA1/2 mutations and 445 women without these mutations with early breast cancer. Patients with BRCA1/2 mutations were treated with breast-conserving therapy (removal of the cancer and surrounding tissue), radiation therapy with or without oophorectomy. Patients without these mutations were treated with breast-conserving therapy and radiation therapy.
At ten and fifteen years, the estimated results are as follows:
- Cancer recurrences within the breast of the original cancer were similar between women with BRCA1/2 mutations who underwent an oophorectomy and those without BRCA1/2 mutations.
- Cancer recurrences within the breast of the original cancer among women with BRCA1/2 mutations were higher among women who did not undergo an oophorectomy compared to women without BRCA1/2 mutations.
- The rates of developing breast cancer in the other breast remained significantly higher in women with BRCA1/2 mutations, regardless of treatment choice, compared to women without these mutations.
The researchers concluded that breast-conserving therapy, radiation therapy, and oophorectomy for women with BRCA1/2 mutations diagnosed with early breast cancer lead to recurrence rates within the breast where the cancer originated that are similar to such recurrences in women without these mutations who undergo breast-conserving therapy and radiation therapy. However, women with BRCA1/2 mutations who do not undergo oophorectomy have higher rates of recurrences within the breast of the original cancer. Furthermore, all women with early breast cancer and BRCA1/2 mutations have an increased risk of developing breast cancer in the opposite breast when compared to other women with breast cancer.
Reference: Pierce L, Levin A, Rebbeck T, et al. Multi-Institutional 10-Year Results of Breast-Conserving Surgery and Radiotherapy in BRCA1/2-Associated Stage I/II Breast Cancer. *Journal of Clinical Oncology.*2006; published online ahead of print Apr 24 2006. DOI: 10.1200/JCO.2005.02.7888.
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