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Breast cancer is a malignant (cancerous) tumor that forms in the tissues of one or both breasts. Although breast cancer primarily affects women, it can also occur in children and men. For the most part, the content in this section describes breast cancer in women.

 

According to the American Cancer Society (ACS), in the United States breast cancer is the most common cancer among women and is the second leading cause of cancer death in women (after lung cancer). In their most recent findings, the ACS estimated that 182,460 new cases of breast cancer were diagnosed among women in 2008. Breast cancer affects one in eight women, but it can be a highly curable disease if detected and treated early.

 

Breast Cancer Symptoms

Get familiar with common warning signs of breast cancer.

Screening & Diagnosis

Learn about screening tests for woman with no symptoms, plus diagnostic tests used when breast cancer is suspected.

Types and Grades of Breast Cancer

Here's a quick overview of some of the more common types of breast cancer.

Stages of Breast Cancer

Find out how a cancer is classified based on its size and how far it’s spread—key factors that influence treatment.

Risk Factors

Who is most at risk of getting breast cancer.

Questions & Answers

Your questions answered, from information about hormone replacement therapy to the use of Tamoxifen.