There are two principal methods of breast cancer staging. The first system of staging speaks of Stages 0 through IV which indicate the size and the invasiveness of the tumor and also whether the cancer is present in the lymph nodes or if it has spread to parts of the body other than the breast.
It will also indicate whether the cancer is local (only present in the breast) whether it is regional (spread to the lymph nodes) or distant (spread to other parts of the body).
Breast cancer staging also depends upon another system called the TNM system. Here T stands for Tumor, N stands for node, and M stands for metastasis. This staging system describes the breast cancer in this manner-
The tumor (size) category
The term TX refers to no tumor being found or measured. T0 signifies the absence of a primary tumor. TIS refers to the tumor being “in situ” which means that the tumor is confined to its place and has not spread to healthy surrounding breast tissue.
Stages T1 through T4 refer to the size of the tumor and the extent to which neighboring breast tissue has been invaded by the tumor.
Involvement of the lymph nodes
This breast cancer staging method refers to the extent to which the lymph nodes are or aren’t involved. NX and N0 mean that the cancer has not spread to the lymph nodes. Categories N1 though N3 refer to the extent to which the cancer is found to be present in the lymph nodes.
The metastasis category
This category tells us whether or not the cancer has traveled from the breast to other parts of the body. MX and M0 categories refer to the absence of any metastasis or the metastasis not being found or measurable. M1 refers to metastasis of the cancer to a different location in the body.
How breast cancer staging affects prognosis
The data collated under the TNM system will indicate the extent of severity of the cancer and the prognosis of the individual. For instance if the tumor is of a T1 category, but the N and M categories are 0, that would mean that the tumor itself is about 2 centimeters or less in size and that and that there is no metastasis or involvement of the lymph nodes.
In other words a T1 N0 M0 breast cancer would be classified as Stage I of the breast cancer and the prognosis can be considered to be fairly good since this is a highly treatable stage of the breast cancer.
Other diagnostic tools for determining prognosis
If breast cancer is diagnosed, other tests will be performed for the purposes of breast cancer staging and prognosis. Mammograms will indicate the presence of any other abnormalities in the breast. A chest X=ray will indicate if the cancer has spread to the lungs. In addition bone scans may be done to check if the cancer has spread to the bones.
A CT scan may also be performed to see if the cancer has spread to other parts of the body such as the organs in the abdominal cavity and so on. An MRI may also be performed for a more thorough look at the breast particularly to check any abnormalities present in the breast other than the one where the tumor is present.