Estimating an individual woman's risk of breast cancer is no easy task.
Risk is predicted over the next five years and over the course of a lifetime.
The results are compared to the numbers of a woman of the same age having no risk factors for the disease. The risk of developing breast cancer increases with age. Most breast cancers occur in women over the age of 50. Women who had their first menstrual period before the age of 12 are at slightly greater risk for breast cancer. Women who had their first child after age 30 or who have never borne a child have a greater risk of developing breast cancer.