Except for skin cancers, breast cancer is the most common type of cancer in women in the U.S.

Breast cancer accounts for 1 of every 3 cancers found in women in the U.S. and is the second most common cause of cancer death. However, progress in treatment and early detection has led to improved survival and breast cancer mortality in the U.S. has declined by more than 40 percent since 1989.

All women are at risk of breast cancer. Researchers have identified a number of risk factors that increase a person’s chance of developing breast cancer. The 2 most common risk factors are being born female and getting older. Other risk factors are related to genetics and family health history, as well as reproductive and lifestyle choices. The presence of risk factors does not guarantee a person will develop breast cancer, nor does the absence of risk factors guarantee someone won’t develop breast cancer. Cancer occurs when cells begin to grow and divide out of control. Cancer cells are abnormal cells that outlive normal cells and develop into malignant tumors.