Stages of Breast Cancer
Breast Cancer

The pathology report will include information about the stage of breast cancer and will inform the doctor if it is limited to one area in the breast or has spread to other parts of the breast or body. Stage of breast cancer is based on 4 characteristics:

  • Size of the cancer
  • Whether the cancer is invasive or not
  • Whether the cancer has reached the lymph nodes or not
  • Whether the cancer has spread to other parts of the body other than the breast.

Stages of breast cancer include:

  1. Stage 0: non-invasive breast cancer or what is named Ductal carcinoma in Situ (DCIS). There is no evidence of cancer cells or abnormal cells breaking out of the part of the breast in which they started, or invading neighboring normal tissue.
  2. Stage I: invasive breast cancer where cancer cells have broken through to or invading normal surrounding breast tissue.  Stage I is divided into subcategories known as IA and IB.
    • 1A: tumor measures up to 2 centimeters AND the cancer has not spread outside the breast; no lymph nodes are involved.
    • 1B: tumor in the breast that is no larger than 2 centimeters, and there are small groups of cancer cells which are larger than 0.2 millimeter but not larger than 2 millimeters in the lymph nodes.
  3. Stage II: it is invasive cancer and is further subdivided into IIA and IIB.
    • IIA: no tumor can be found in the breast, but cancer (larger than 2 millimeters) is found in 1 to 3 axillary lymph nodes (the lymph nodes under the arm) or in the lymph nodes near the breast bone (found during a sentinel node biopsy) OR the tumor measures 2 centimeters or smaller and has spread to the axillary lymph nodes OR the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes
    • IIB: the tumor is larger than 2 centimeters but no larger than 5 centimeters; small groups of breast cancer cells larger than 0.2 millimeter but not larger than 2 millimeters are found in the lymph nodes OR the tumor is larger than 2 centimeters but no larger than 5 centimeters; cancer has spread to 1 to 3 axillary lymph nodes or to lymph nodes near the breastbone (found during a sentinel node biopsy) OR the tumor is larger than 5 centimeters but has not spread to the axillary lymph nodes.
  4. Stage III: Invasive cancer further subdivided into IIIA,IIB and IIIC.
    • IIIA: no tumor is found in the breast or the tumor may be any size; cancer is found in 4 to 9 axillary lymph nodes or in the lymph nodes near the breastbone (found during imaging tests or a physical exam) OR the tumor is larger than 5 centimeters; small groups of breast cancer cells (larger than 0.2 millimeter but not larger than 2 millimeters) are found in the lymph nodes OR tumor is larger than 5 centimeters; cancer has spread to 1 to 3 axillary lymph nodes or to the lymph nodes near the breastbone (found during a sentinel lymph node biopsy)
    • IIIB: the tumor may be any size and has spread to the chest wall and/or skin of the breast and caused swelling or an ulcer AND may have spread to up to 9 axillary lymph nodes OR may have spread to lymph nodes near the breastbone
    • Inflammatory breast cancer is considered stage IIIB. features of inflammatory breast cancer include reddening of a large portion of the breast skin, the breast feels warm and may be swollen and cancer cells have spread to the lymph nodes and may be found in the skin.
    • IIIC: there may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast AND the cancer has spread to 10 or more axillary lymph nodes OR the cancer has spread to lymph nodes above or below the collarbone OR the cancer has spread to axillary lymph nodes or to lymph nodes near the breastbone
  5. Stage IV: invasive breast cancer that has spread beyond the breast and nearby lymph nodes to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver, or brain.