Breast cancer risk after chemoprevention in BRCA1 versus BRCA2 mutation carriers

Problem: Breast cancer is one of the most common types of cancer and a leading cause of cancer-related deaths among women in the United States. The average American woman carries a 12% lifetime risk for developing breast cancer. A woman with a mutation in a BRCA1 or BRCA2 gene has an increased lifetime risk for developing breast cancer to that of 60-85%. Research has identified various methods for reducing a woman's risk for breast cancer including increased surveillance, chemoprevention, and prophylactic surgery. Methods: A review of the literature was performed to investigate whether chemoprevention or prophylactic surgery (bilateral mastectomy and bilateral oophorectomy) has the highest efficacy in reducing the incidence of breast cancer in female patients at high risk for the disease. Results: The literature search yielded 24 articles of which eight were ultimately used in this literature review. Conclusions: Bilateral mastectomy was found to have the greatest risk-reducing potential at nearly 90%. Bilateral oophorectomy appears to reduce the risk of breast cancer by 45-70% in high-risk women and chemoprevention with tamoxifen or raloxifene therapy showed an approximate 50% risk reduction in breast cancer incidence. This author identified several gaps within the literature including varying definitions for "high-risk" patients and a failure to differentiate between BRCA1 and BRCA2 subjects when analyzing the effects of the preventive measures.