Does Tamoxifen Prevent Contralateral Breast Cancer in BRCA Mutation Carriers?

Women with BRCA mutations have high lifetime breast cancer risk that can be reduced by >90% with bilateral mastectomy and by 50% with bilateral salpingo-oophorectomy (BSO). However, many mutation carriers choose not to undergo these risk-reducing surgeries. Although adjuvant tamoxifen lowers risk for contralateral breast cancer (CBC) by half in the general population of women with breast cancer, its efficacy for preventing CBC in BRCA mutation carriers has not been thoroughly studied; thus, tamoxifen is not commonly used in this setting. Now, investigators have pooled data from three cohort studies to analyze CBC risk in 2464 BRCA1 or BRCA2 carriers with breast cancer (median time since first diagnosis, 6.6 years).

One quarter of BRCA1 carri…