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About Breast Cancer

What is Breast Cancer?

Cancer is a word that describes a wide range of similar diseases. There are over 100 different types of cancer, but they all have a lot in common. Primarily, all cancers are an extreme growth of abnormal cells that your body can't stop or destroy. These cell growths can spread from one part of the body to another, and they destroy normal, healthy cells.
Cancer cells often form a lump called a tumor, but the word ‘tumor’ does not always mean cancer, or ‘malignant.'  Some tumors are ‘benign’, or non-cancerous.

Breast Biopsy Health Stats

 Download Quick Facts: Breast Cancer PDF

Cancer cells can start growing anywhere in the body. The type of cancer a person has will depend on where the cancer cells first began to grow and the kinds of cell abnormalities found. Different treatments are used based on the type of cancer, as each cancer type can behave differently.  Some types of cancer grow and spread very quickly, while others grow and spread slowly.  If the cancer has spread to a new location within the body, then the new growth is called a ‘metastasis.'
Cancer that first begins to grow within the breast is called breast cancer. Breast cancer is the second-most-common form of cancer diagnosed in women, after skin cancer.2  It’s estimated that 1 in 8 women will develop breast cancer at some point in her life, and for men, the estimate is 1 in 1,000.13 If you or your loved one has been diagnosed with breast cancer, you should know that a variety of treatments are available.

Doctors will perform multiple tests to help identify the cancer and the type.  Once cancer is diagnosed, it will then be described by the ‘stage’.  The stage of cancer is based on the size of the cancer and if it has spread, or ‘metastasized’, anywhere else within the body. Doctors may describe the stage using a number (0-IV or 0-4), or they may use the TNM system (click here for a detailed explanation of the TNM system from the National Cancer Institute).12 Stages with low numbers mean that the cancer hasn't spread very far or at all. Stages with high numbers mean that the cancer has spread, which tends to make the cancer more serious and more difficult to treat.
The American Cancer Society has a Cancer Glossary, which can be used to explain cancer-related words more clearly.


  1. (WebMD: Breast Cancer Health Center)
  2. (Mayo Clinic: Breast Cancer)
  3. (National Cancer Institute: Cancer Statistics) and (National Cancer Institute: SEER Stat Fact Sheets: Female Breast Cancer)
  4. (World Health Organization: Cancer Fact Sheet)
  5. (MedlinePlus: Breast Cancer)
  6. (National Cancer Institute: Breast Cancer—Health Professional Version)
  7. (National Cancer Institute: Breast Cancer—Patient Version)
  8. (American Cancer Society: Breast Cancer)
  9. (American Cancer Society: Breast Cancer Risk Factors)
  10. (American Cancer Society: Guidelines for the Early Detection of Cancer)
  11. (American Cancer Society: Cancer Glossary)
  12. (National Cancer Institute: Staging)
  13. (American Cancer Society: Breast Cancer in Men Key Statistics)
  14. (MedlinePlus definition of general anesthesia)