Staging is the most critical requirement for deciding on the most accurate and effective treatment once the finding of breast cancer has been confirmed.
Simply put, staging means investigating whether cancer cells have spread within the breast or to other parts of the body.
There are two types of staging in breast cancer: clinical staging and pathological staging.
Clinical staging: It is staging performed using imaging techniques together with physical examination including the breast and the axilla.
Pathological staging: It is performed, in addition to clinical staging, by pathological examination of the removed breast tissue and axillary lymph nodes.
The TNM system is used for staging cancer.
T indicates the tumor. (It shows its size and how far it has spread into the breast or to organs.)
N indicates the status of the lymph nodes.
M indicates whether the cancer has metastasized (spread).
Some numbers and letters that come after T, N and M are used for details about the tumor, lymph nodes and metastasis.
The two most important factors in the prognosis of breast cancer:
- The number of axillary lymph nodes involved
- Metastatic disease.
In the staging system, the stage is indicated by a number between Stage 0 and 4.
Stage 0 (Carcinoma in situ): In situ cancers are cancers that have remained in place and have not spread to the surroundings.
Stage 1 The tumor size is 2 cm or smaller and the cancer cells have not spread outside the breast (to the lymph nodes).
Stage 2A The tumor is 2 cm or smaller and has spread to the lymph nodes under the arm, or
the tumor is larger than 2 cm and smaller than 5 cm and has not spread to the lymph nodes under the arm.
Stage 2B The tumor is larger than 2 cm and smaller than 5 cm and has spread to the lymph nodes under the arm, or
the tumor is larger than 5 cm but has not spread to the lymph nodes under the arm.
Stage 3A The tumor is 5 cm or smaller and has spread to the lymph nodes under the arm and the lymph nodes are attached to surrounding tissues or to each other, or the tumor is larger than 5 cm and has spread to the lymph nodes under the arm and the lymph nodes are attached to surrounding tissues or to each other.
Stage 3B The tumor can be of any size and has spread to tissues adjacent to the breast (the skin or chest wall, ribs or muscles in the chest wall) or there is an orange-peel appearance in the breast,
the tumor cells have spread to the lymph nodes inside the chest cage (under the ribs); inflammatory breast cancer is considered stage 3B.
Stage 3C The tumor can be of any size and may have spread to tissues adjacent to the breast (the skin or chest wall, ribs or muscles in the chest wall); the tumor cells have spread both to the lymph nodes under the arm and to the lymph nodes inside the chest cage (under the ribs), or the tumor has spread to the lymph nodes under the collarbone, with or without spread to the lymph nodes under the arm. The tumor cells have spread to the lymph nodes above the collarbone; with or without spread to the lymph nodes under the arm and inside the chest cage.
Stage 4 Cancer cells have spread outside the breast to other parts of the body (such as the bones, lungs, liver or brain).
