Nonsurgical Prevention Strategies in <b><i>BRCA1</i></b> and <b><i>BRCA2</i></b> Mutation Carriers

Background: Female carriers of a BRCA1 or 2 germline mutation face a high lifetime risk to develop breast and ovarian cancer. Risk-reducing surgery, such as prophylactic bilateral mastectomy and prophylactic bilateral salpingo-oophorectomy, are proven strategies to prevent breast and ovarian cancer. These procedures are, however, associated with considerable side effects, and the uptake of these highly effective interventions is therefore low in many countries. This highlights the need for alternative and noninvasive strategies for risk reduction in mutation carriers. Summary: While endocrine treatments with tamoxifen and aromatase inhibitors (AI) have been shown to be effective in secondary prevention, their benefit in primary prevention has never been prospectively evaluated. Moreover, their side effect profile makes them inappropriate candidates for chemoprevention in healthy premenopausal women. Recently, denosumab, a well-tolerated osteoprotective drug, has been shown to have an antitumoral effect on RANK+, BRCA1 -deficient luminal progenitor cells in vitro, and has been demonstrated to abrogate tumors in BRCA1 -deficient mouse models. Key Message: The prospectively randomized, double-blind BRCA-P trial is currently investigating the preventative effect of denosumab in healthy BRCA1 germline mutation carriers.