What Is Breast Cancer Staging?
Breast cancer staging covers from stage 0 to stage IV. Cancer staging is a uniform way for health care providers to know the location, size and type of tumor involved, and if the tumor has spread or metastasized to other parts of the body. In addition to the stage 0 to IV designation, subcategories further delineate the invasiveness of the cancer, according to the National Cancer Institute. An understanding of the staging process gives the basis for recognizing the prognosis for each stage.
Stages 0 and I
Stage 0 breast cancer is a non-invasive cancer, in which there are no cancer cells noted outside the area of the breast where they started. There is no invasion of surrounding normal tissue. The five year survival rate, according to the American Cancer Society for Stage 0 is 93 percent.
Stage I breast cancer is further divided into stages IA, in which the tumor is no larger than 2 centimeters and is contained within the breast, and stage IB, where the tumor is no larger than 2 centimeters and small clusters of cancer cells are found in the lymph nodes. Stage I survival rate is at 88 percent.
Stage IIA breast cancer diagnostic criteria includes:
- No tumor in the breast, but cancer in the lymph nodes under the arm; or
- A tumor up to 2 centimeters has spread to the lymph nodes under the arm; or
- A tumor between 2 and 5 centimeters has spread to the axillary lymph nodes; or
- The tumor is larger than 5 centimeters and is contained in the breast.
The five year survival rate for stage IIA breast cancer is 81 percent.
Stage IIB has only two criteria. The tumor is either between 2 and 5 centimeters and is found in the axillary lymph nodes, or it is larger than 5 centimeters and is not found in the lymph nodes under the arm. Stage IIB survival is at 74 percent.
Stage IIIA breast cancer is an invasive cancer which meets one of the following criteria:
- No tumor is in the breast, but cancer is found in axillary lymph nodes stuck together or near the breastbone; or
- The tumor is up to 5 centimeters in the breast and the cells that are stuck or clumped together have spread to the axillary nodes; or
- The tumor is larger than 5 centimeters and spread to lymph nodes in the armpit.
The survival rate for stage IIIA is at 67 percent.
Stage IIIB breast cancer can be any size cancer that has spread to surrounding chest wall or breast tissue and also involves the lymph nodes in the armpit or near the breastbone. Stage IIIB survival is at 41 percent.
Stage IIIC breast cancer may have no cancer in the breast; a tumor of any size may be in the chest wall or skin of the breast. In addition, cancer is found in lymph nodes near the collarbone, breast bone and armpit. Stage IIIC breast cancer is further divided into operable and inoperable as follows:
- Operable: found in at least 10 axillary lymph nodes; or any lymph nodes below the collarbone; or in lymph nodes near the breastbone and the armpit
- Inoperable: breast cancer that has spread to any of the lymph nodes above the collarbone.
Survival for stage IIIC breast cancer is at 49 percent.
Stage IV breast cancer is an invasive cancer that has spread to other locations in the body, such as the lungs, bone, brain or liver. Stage IV is considered late-stage cancer with a survival rate of 15 percent.
National Cancer Institute: Stages of Breast Cancer https://www.cancer.gov/cancertopics/pdq/treatment/breast/Patient/page2
American Cancer Society: Breast Cancer Survival Rates by Stage https://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-survival-by-stage