Dr. Alexandra J. van den Broek of the Netherlands Cancer Institute in San Antonio (EGMN) reported at the San Antonio Breast Cancer Symposium that certain factors predict the high risk of contralateral breast cancer in breast cancer patients carrying a BRCA mutation. key predictors in subjects in the BOSOM (Study of Mutations and Breast Cancer Prognosis) include: age at first breast cancer diagnosis, whether the breast cancer is triple negative (estrogen receptor negative, progesterone receptor negative, HER2 receptor negative). The BOSOM study enrolled 5,065 consecutive female patients diagnosed with breast cancer before the age of 50 years from 10 Dutch hospitals, and all subjects were tested for BRCA mutations. the prevalence of BRCA1 mutations was 3% and BRCA2 mutations was 1%. The 10-year cumulative risk of contralateral breast cancer in patients without BRCA mutations was 6%, while the risk was as high as 11% for BRCA1 mutation carriers and 20% for BRCA2 mutation carriers. Among BRCA mutation carriers, those diagnosed for the first time before age 41 were more likely to develop contralateral breast cancer, with a cumulative 10-year risk of 26%, while the risk for the low-risk subgroup (diagnosed with non-triple-negative breast cancer between ages 41 and 50) was only about 4%. BRCA mutation carriers diagnosed with triple-negative breast cancer between the ages of 41 and 50 years were also at high risk for contralateral breast cancer, with a 10-year cumulative risk of 15%. The number of BRCA mutation carriers in this consecutive cohort of breast cancer patients is quite small, so the BOSOM results need to be confirmed by additional data. If confirmed, the investigators believe that the recommendations in the practice guidelines for prevention and screening for contralateral breast cancer after the development of breast cancer in BRCA mutation carriers should be modified. The study was initiated by the Dutch Cancer Society. van den Broek, MD, claims no relevant conflicts of interest.