Cancer is a disease in which cells become abnormal and form more cells in an uncontrolled way. With breast cancer, the cancer begins in cells that make up the breasts — usually in the tubes that carry milk to the nipple or the glands that make milk. The cancerous cells form a mass of tissue called a tumor. Sometimes, the cancer spreads to other parts of the body.
Other than skin cancer, breast cancer is the most common cancer in American women. It also is the second-leading cancer killer of women, after lung cancer. Every woman has a chance of getting breast cancer. About 1 in 8 women will find out she has breast cancer at some point in her life. This might sound scary. But today, most women with breast cancer survive it. With breast cancer screening, including mammograms, doctors often can find cancer early. Treatment has the best chance of success when cancer is found early.
For more information about breast cancer, call womenshealth.gov at 800-994-9662 (TDD: 888-220-5446) or contact the following organizations:
Content last updated July 16, 2012.
Resources last updated December 08, 2008.