In the Netherlands, approximately 12,000 women are diagnosed with breast cancer annually, of whom about 5-10% carry a mutation in the BRCA1 or BRCA2 gene. Genetic counseling and DNA testing are usually offered to selected patients after primary treatment has been completed (e.g. the first year after diagnosis). For women with a mutation in one of the two breast-ovarian cancer syndrome genes, chances of a second breast cancer are high, and therefore a proportion of these women may opt for preventive measures in addition to their immediate breast cancer treatment. Contralateral prophylactic mastectomy significantly reduces this risk, and is associated with a reduction in mortality. Genetic counseling and testing for breast cancer typically takes approximately 4-6 months to complete.