Staging refers to the extent of your cancer, such as how large the tumor is and if it has spread. A cancer is always referred to by the stage it was given at diagnosis, even if it gets worse or spreads. The TNM system is the most widely used tool to describe the stage of breast cancer. The staging guidelines were updated in 2018 and the prognostic stage was added. The prognostic stage adds the grade (G), ER/PR, Her2/neu and status to the TNM system. With this additional information, stage grouping for breast cancer has become more complex than other cancers. Because of this, it is best to ask your doctor about your specific stage and what it means.
T followed by a number from 0 to 4 describes the primary tumor’s size and if it has spread to the chest wall under the breasts. The higher the T number means the larger the tumor in size and if it has spread to tissues near the breast.
N followed by a number from 0 to 3 indicates if the cancer has spread to lymph nodes near the breast and the number of lymph nodes involved.
M followed by a 0 or 1 indicates if the cancer has spread to distant organs, the lungs, liver or bones.
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TX: The primary tumor cannot be evaluated.
T0: Main tumor cannot be found.
Tis: Carcinoma in situ; the cancer has not spread into the surrounding tissue.
T1: Tumor is 2 cm or smaller in diameter.
T2: Tumor is larger than 2 cm but smaller 5 cm.
T3: Tumor is larger than 5 cm in diameter.
T4: Tumor has grown into the chest wall, skin or both.
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NX: The lymph nodes were not evaluated.
N0: There is no cancer in nearby lymph nodes or areas of cancer smaller than 0.2 mm.
N1: The cancer has spread to 1 to 3 axillary lymph nodes and/or internal mammary lymph nodes.
N2: The cancer has spread to 4 to 9 axillary lymph nodes or it has spread to the internal mammary lymph nodes, but not the axillary lymph nodes.
N3: The cancer has spread to 10 or more axillary lymph nodes or it has spread to lymph nodes under the clavicle or collarbone. It may also have spread to internal mammary lymph nodes.
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MX: Distant spread cannot be evaluated.
M0: Cancer has not spread to other parts of the body.
M0(i+): There is not clinical or radiographic evidence of distant metastases. Microscopic evidence of tumor cells can be found in the blood, bone marrow or other lymph nodes that are no larger than 0.2 mm.
M1: Cancer has spread to other parts of the body; there is evidence of metastasis.
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G1: Low combined histologic grade (favorable).
G2: Intermediate combined histologic grade (moderately favorable).
G3: High combined histologic grade (unfavorable).
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Does the cancer have the protein called an estrogen receptor?
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Does the cancer have the protein called a progesterone receptor?
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Does the cancer make too much of a protein called HER2?
Oncotype DX is a test they do on 21 genes linked to cancer recurring within the next 10 years and how well it will react to chemotherapy. A low score- less than 19 means it is less likely to recur and less likely for the chemotherapy to be beneficial.
These staging guidelines help describe breast cancer in great detail. But, for many cancers, the TNM combinations are grouped into five less-detailed stages.
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Stage 0 - Abnormal cells are present but have not spread to nearby tissue. Also called carcinoma in situ, or CIS. CIS is not cancer, but it may become cancer..
Stage I, II, and III - Cancer is present. The higher the number, the larger the cancer tumor and the more it has spread into nearby tissues.
Stage IV - The cancer has spread to distant parts of the body.
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