Assessing breast cancer risk: genetic factors are not the whole story.

Genetic syndromes that convey a significant risk of breast cancer are responsible for a small but significant percentage of these cancers. However, the vast majority of breast cancers occur in women with no family history of the disease. Nongenetic risk factors include age, previous breast disease, breast tissue density, radiation exposure, and lifestyle factors, such as weight, exercise, and alcohol consumption. In this article, the authors outline genetic and other risk factors for breast cancer, explore risk-reduction strategies, and encourage primary care physicians to assess breast cancer risk in all their patients.