Life-saving, risk-reducing medical interventions are required for women with a BRCA1/2 mutation. Interventions comprise a four-stage approach that involves risk assessment, genetic counseling, gene-mutation analysis and medical intervention strategies. Genetic counseling should be offered at specialized familial breast-cancer clinics and gene-mutation analysis should be recommended on the basis of personal and family-history-based risk criteria. Prophylactic bilateral salpingo-oophorectomy appears to offer the optimal benefit-risk ratio compared with prophylactic bilateral mastectomy, chemoprevention, or intensified surveillance. Tamoxifen is an alternative approach only for BRCA2 mutation carriers. The comprehensive, clinical decision-making Ioannina algorithm provided here can facilitate the complex preventive strategic approach. Newly diagnosed BRCA1/2 carriers might benefit from extensive surgery and a specific pharmacological treatment, but data to support this strategy are limited. Microarray gene-expression studies show that breast tumors from BRCA1 carriers are predominantly of basal subtype (i.e. triple negative) and BRCA2 carriers are of luminal subtype (i.e. estrogen-receptor-positive). Although optimum management of women with familial susceptibility to breast and ovarian cancer has not yet been prospectively validated, data indicate substantial benefits when an individualized evidence-based prevention strategy is provided by an experienced team.