Breast Cancer Stages
Breast cancer staging describes the extent of the disease, including the size of the tumor, and lymph node involvement, and whether breast cancer has spread to distant parts of the body (metastasis). The staging of breast cancer helps to determine the recommended treatment, along with other characteristics of cancer like hormone receptor status, human epidermal growth factor receptor 2 (HER2) status, whether the patient is postmenopausal or not, and the general health of the patient.1
Figure 1. Overview of breast cancer stages
Breast cancer staging is often done according to the American Joint Committee on Cancer (AJCC) system and is based on the tumor, node, and metastasis (TNM) classification. See below for TNM classifications.
Table 1. Breast cancer classifications
Additional Information can on tumor size, lymph node involvement, and metastasis can be found below:
Breast cancer tumor size
The size of the tumor is measured in millimeters and is represented by T in the TNM system.
Table 2. Tumor classifications
Lymph node involvement
When breast cancer spreads through the lymphatic system to the lymph nodes, it can spread to the:
- Axillary lymph nodes, which are found under the arm
- Clavicular lymph nodes – including supraclavicular and infraclavicular – which are found above (supra-) and below (infra-) the collarbone
- Mammary lymph nodes, which are within the breast tissue
Table 3. Lymph node classification
Metastatic breast cancer
If breast cancer spreads to other organs in the body, it most commonly spreads to the bones, lungs, liver, or brain.2
Table 4. Classification of breast cancer metastasis
|Stage||Tumor size (T)||Node involvement (N)||Metastases(M)|
|Stage IIIC||Any T||N3||M0|
|Stage IV||Any T||Any N||M1|
- Breast cancer treatment – PDQ, Stage Information. National Cancer Institute. Available at https://www.cancer.gov/types/breast/hp/breast-treatment-pdq#section/_27. Accessed 8/16/18.
- https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/stages-of-breast-cancer.html. Accessed 8/16/18.