Among BRCA1/2 carriers, we found a statistically significant risk-reducing effect on breast cancer according to BRRM (with or without RR-BSO) (adjusted HR 0.06, CI 0.02–0.25) (Table 3), but not according to RR-BSO (adjusted HR 1.31, CI 0.90–1.91). Here, BRCA1 is linked to breast cancer.