Recognition and management of hereditary breast cancer syndromes.

Clinicians should recognize the genetic syndromes that predispose to the development of breast cancer so that patients may be afforded the opportunity to have genetic testing to assist them and their family members in making medical management decisions. Approximately 80%-90% of hereditary breast cancer cases are caused by mutations in the BRCA1 and BRCA2 genes. Other important clinical genetic predispositions include Cowden syndrome, Li-Fraumeni syndrome, Peutz-Jeghers syndrome, and ataxia-telangiectasia. The key to identifying women who are at risk for a hereditary breast cancer lies in obtaining an adequate, three-generation family history, including ethnic background. For unaffected women, breast cancer risks can be estimated using the quantitative models of Gail and Claus, but there are limitations to these models. Other quantitative models predict the likelihood that a patient is carrying a mutated gene. Genetic testing is available at selected laboratories for each of the hereditary syndromes described, and there are three possible outcomes to testing. These outcomes and their management implications are described in detail. Clinical management options for women at high risk for breast cancer include surveillance, chemoprevention, and prophylactic surgery. Application of these principles can reduce morbidity in women with genetic predispositions to breast cancer.