Definition

Breast cancer is cancer of the breast. Cancer (see cancer entry) is a disease in which cells begin to grow rapidly and out of control. Cancer cells can travel through the body by way of blood or lymph nodes. They can then come to rest and start growing in other parts of the body.

Description

Every woman is at risk for breast cancer. The risk varies with age. At age twenty-five, a woman's risk is about 1 in 20,000. At age forty-five, it is 1 in about 100. At age eighty-five, it is more than 1 in 10. About 80 percent of all breast cancers are found in women over the age of fifty.

Causes

Researchers do not know how normal cells suddenly become cancerous. Thus, the fundamental cause or causes of breast cancer are still a puzzle. Scientists do know that certain risk factors are related to the development of breast...