Later studies estimated even higher incidences of contralateral breast cancer within the first 5 years of follow-up after the primary breast cancer: 12–33% among BRCA1 or BRCA2 mutation carriers (2.4–6.5% per year) (Robson et al, 1998; Verhoog et al, 1998, 1999) as compared to a 0.4–1% per year for breast cancer patients in general (Fisher et al, 1984). This evidence concerns the gene BRCA1 and breast cancer.