Breast Cancer Staging

Learn how Dr. Levine and the breast team tackle any stage of breast cancer with a multidisciplinary approach.

Breast cancer staging refers to how large the breast tumor has grown and whether it has spread beyond the breast to lymph nodes or distant sites. Your breast cancer will be characterized using these stages:

  • Stage 0 (carcinoma in situ): The term, in situ means the cancer cells are found only in their initial location. For example, ductal carcinoma in situ means abnormal cells have not spread outside the ducts. Lobular carcinoma in situ means the abnormal cells are confined to the lobules. In Paget disease of the nipple, cancer cells are found only in the nipple.
  • Stage IA: The tumor 2 centimeters (cm) or smaller, and cancer cells have not spread beyond the breast.
  • Stage IB: The tumor is 2 cm or smaller, or possibly no breast tumor, and small clusters of cancer cells are found in lymph nodes.
  • Stage IIA: refers to either of these situations:
    • The breast tumor is 2 cm or small, or possibly no breast tumor, by clusters of cancer cells (2 mm or larger) are found in 1 to 3 underarm lymph nodes or in the nodes near the breastbone;
    • The breast tumor is between 2 cm and 5 cm in size, with no lymph node involvement
  • Stage IIB: refers to one of these situations:
    • The breast tumor is between 2 cm and 5 cm in size, and small clusters of cancer cells (smaller than 2 mm) are found in lymph nodes
    • The breast tumor is between 2 cm and 5 cm in size, and cancer has spread to 1 to 3 underarm lymph nodes or the nodes along the breast bone
    • The breast tumor is larger than 5 cm, with no lymph node involvement
  • Stage IIIA: refers to one of these situations:
    • The breast tumor is 5 cm or smaller and has spread to 4 to 9 underarm lymph nodes that are attached to each other or nearby tissue, or to the lymph nodes behind the breastbone;
    • The breast tumor is larger than 5cm and small clusters of cancer cells (less than 2mm) are found in lymph nodes.
    • The breast tumor is larger than 5cm and has spread to 1 to 3 underarm nodes or to the nodes near the breastbone.
  • Stage IIIB: refers to a breast tumor of any size that has grown into the chest wall or skin of breast causing swelling or an ulcer and the cancer may have spread to:
    • Up to 9 underarm lymph nodes; or
    • The lymph nodes behind the breastbone
  • Stage IIIC: refers to a tumor of any size that has spread to the chest wall, and/or the skin of the breast and has spread to:
    • Up to 10 or more underarm nodes
    • Lymph nodes above or below the collarbone
    • Underarm nodes and nodes near the breastbone Cancer that has spread to the skin may be inflammatory breast cancer.
  • Stage IV: Tumor may be any size and cancer cells have spread to other areas such as the lungs, liver, bones or brain.