Breast Cancer

What is Breast Cancer?

How Tumors Form

The body is made up of many types of cells. Normally, cells grow, divide and produce more cells as needed to keep the body healthy. Sometimes, however, the process goes wrong. Cells become abnormal and form more cells in an uncontrolled way. These extra cells form a mass of tissue, called a growth or tumor. Tumors can be benign, which means not cancerous, or malignant, which means cancerous. Breast cancer occurs when malignant tumors form in the breast tissue.

Who Gets Breast Cancer?

Breast cancer is one of the most common cancers in American women. It is most common among women between the ages of 45-85.

(Watch the video to learn more about breast cancer survival rates. To enlarge the videos appearing on this page, click the brackets in the lower right-hand corner of the video screen. To reduce the videos, press the Escape (Esc) button on your keyboard.)

Men can get breast cancer too, although they account for only 1 percent of all reported cases.

Read more about breast cancer in men.

When Breast Cancer Spreads

When cancer grows in breast tissue and spreads outside the breast, cancer cells are often found in the lymph nodes under the arm. If the cancer has reached these nodes, it means that cancer cells may have spread, or metastasized, to other parts of the body.

When cancer spreads from its original location in the breast to another part of the body such as the brain, it is called metastatic breast cancer, not brain cancer. Doctors sometimes call this "distant" disease.

Learn about different kinds of breast cancer.

Breast Cancer is Not Contagious

Breast cancer is not contagious. A woman cannot "catch" breast cancer from other women who have the disease. Also, breast cancer is not caused by an injury to the breast. Most women who develop breast cancer do not have any known risk factors or a history of the disease in their families.

Treating and Surviving Breast Cancer

Today, more women are surviving breast cancer than ever before. Nearly three million women are breast cancer survivors.

(Watch the video to hear a woman discuss surviving breast cancer.)

There are several ways to treat breast cancer, but all treatments work best when the disease is found early. As a matter of fact, when it is caught in its earliest stage, 98.5 percent of women with the disease are alive five years later.

Every day researchers are working to find new and better ways to detect and treat cancer. Many studies of new approaches for women with breast cancer are under way. With early detection, and prompt and appropriate treatment, the outlook for women with breast cancer can be positive.

To learn more about what happens after treatment, see Surviving Cancer.