You will read about possible causes, screening, symptoms, diagnosis, treatment, and supportive care. You will also find ideas about how to cope with the disease.

Scientists are studying breast cancer to find out more about its causes. And they are looking for better ways to prevent, find, and treat it.

NCI provides information about cancer, including the publications mentioned in this booklet. You can order these materials by telephone or on the Internet. You can also read them online and print your own copy.

• Telephone (1-800-4-CANCER): Information Specialists at NCI's Cancer Information Service can answer your questions about cancer. They also can send NCI booklets, fact sheets, and other materials.
• Internet (http://www.cancer.gov): You can use NCI's Web site to find a wide range of up-to-date information. For example, you can find many NCI booklets and fact sheets at http://www.cancer.gov/publications. People in the United States and its territories may use this Web site to order printed copies. This Web site also explains how people outside the United States can mail or fax their requests for NCI booklets.

  You can ask questions online and get help right away from Information Specialists through LiveHelp ¹ at http://www.cancer.gov/cis.

Words that may be new to readers appear in italics. The "Dictionary ²" section explains these terms. Some words in the "Dictionary" have a "sounds-like" spelling to show how to pronounce them.

The breasts sit on the chest muscles that cover the ribs. Each breast is made of 15 to 20 lobes. Lobes contain many smaller lobules. Lobules contain groups of tiny glands that can produce milk. Milk flows from the lobules through thin tubes called ducts to the nipple. The nipple is in the center of a dark area of skin called the areola. Fat fills the spaces between the lobules and ducts.

The breasts also contain lymph vessels. These vessels lead to small, round organs called lymph nodes. Groups of lymph nodes are near the breast in the axilla (underarm), above the collarbone, in the chest behind the breastbone, and in many other parts of the body. The lymph nodes trap bacteria, cancer cells, or other harmful substances.

These pictures show the parts of the breast and the lymph nodes and lymph vessels near the breast.

Understanding Cancer

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body.

Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.

Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form