BRCA1 and breast cancer: Women who underwent RRSO had a lower risk of first diagnosis of breast cancer in BRCA1 mutation carriers; 20% vs 14% (HR= 0.63, 95% CI, 0.41-0.96) and BRCA2 mutation carriers; 23% vs 7% (HR= 0.36, 95% CI, 0.16-0.82).