Staging

Your doctor can give a detailed description of the state of your breast cancer by determining its stage. Staging summarizes important information also referenced in your pathology report, including tumor size, lymph-node status and cancer spread. Your doctor will use the stage of your cancer to choose the best treatment options for you.

 

The State of Your Cancer: Staging

There are five main stages of breast cancer:

  • Stage 0: This cancer has not spread outside of the breast ducts or lobes where it started—it is non-invasive or “in situ.” Learn more about these terms in Breast Cancer Types.
  • Stage 1 or I:  This cancer has a 2 cm or smaller tumor and has not spread to the lymph nodes.
  • Stage 2a or IIa: Three different conditions can qualify as this type of cancer:
    • No cancer exists in the breast, but it has reached the axillary lymph nodes (those under the arm).
    • OR the tumor measures 2 cm or less, and cancer also exists in the axillary lymph nodes.
    • OR the tumor measures 2-5 cm, but cancer cells have not entered the lymph nodes.
  • Stage 2b or IIb: Two conditions qualify as this type of cancer:
    • The tumor measures 2–5 cm and has spread to the axillary lymph nodes.
    • OR the tumor measures more than 5 cm but has not spread to the lymph nodes.
  • Stage 3a or IIIa: Two conditions qualify as this type of cancer:
    • No tumor exists in the breast; cancer is found in lymph nodes near the breastbone or in axillary lymph nodes that are sticking together or to other structures.
    • OR the tumor is any size. Cancer has spread to the lymph nodes near the breastbone or the axillary lymph nodes, which are sticking together or to other structures.
  • Stage 3b or IIIb: This type of cancer has two features:
    • A tumor of any size has spread to the chest wall or skin of the breast.
    • AND cancer cells may have spread to lymph nodes near the breastbone or to axillary lymph nodes that are clumped together or sticking to other structures.
  • Stage 3c or IIIc: This type of cancer has two features:
    • No sign of cancer in the breast or a tumor of any size that has spread to the chest wall or the skin of the breast.
    • AND the cancer has spread to lymph nodes either above or below the collarbone; the cancer may also have spread to axillary lymph nodes or to lymph nodes near the breastbone.
  • Stage 4 or IV: The cancer has spread to other parts of the body, becoming metastatic. Learn more about this and other Breast Cancer Types.