Women with a pathogenic sequence variation in the BRCA1 or BRCA2 gene face a lifetime risk of breast cancer of 70%. Approximately one-third of these women undergo risk-reducing mastectomy, but the majority opt for intensified surveillance. In North America, women with a BRCA1 or BRCA2 sequence variation are recommended to have annual screening with magnetic resonance imaging (MRI) from age 25 or 30 years to age 70 years, and it is important to measure the effectiveness of MRI surveillance in terms of mortality reduction. Here, BRCA1 is linked to breast cancer.