Breast cancer risk factors. Contributions to planning breast cancer control.

The analytic epidemiology of breast cancer has identified several risk factors that may be the bases for developing preventive interventions and refining screening guidelines. Breast cancer risk factors include both personal and environmental sources of risk. The available data, however, do not yet support the feasibility of large scale preventive interventions. Controlled trials will be needed to assess the effectiveness of those approaches. Knowledge of risk factors may be used by physicians to tailor their recommendations for individual patients. Risk factor data also may be used to modify screening recommendations for special populations. A family history of breast cancer may be a basis for modifying screening recommendations but this may be appropriate only for a subset of women with breast cancer in a relative.