Stages of Breast Cancer
Your doctor will assign a stage to your cancer after your physical exam and the initial results from your mammogram or other diagnostic imaging test. The stage may be adjusted after lab reports from your breast biopsy or surgery. In determining the stage of your cancer, your doctor will take into account what is called the T-N-M scale: T meaning tumour size; N relating to the involvement of nearby lymph nodes; and M referring to whether the cancer has metastasized (spread) beyond the breast to other parts of your body.
For breast cancer, there are 5 stages – stage 0 followed by stages 1 to 4.
Stages of breast cancer are classified as follows:
Non-invasive breast cancer such as DCIS– Ductal carcinoma in situ (DCIS) is the presence of abnormal cells inside a milk duct in the breast. It is normally detected via mammogram and considered the earliest form of breast cancer. It is stage 0.
Early stage breast cancer – The tumour is smaller than 5 cm and the cancer has not spread to more than 3 lymph nodes. It includes stages 1A, 1B and 2A.
Locally advanced breast cancer – The tumour is larger than 5 cm and/ or has involved more than 3 nodes. It includes stages 2B, 3A, 3B and 3C.
Metastatic breast cancer – The cancer has spread to other parts of the body. It is stage 4.
Stage 1 breast cancer
Stage 1 describes a very early stage of invasive cancer. At this point, tumour cells have spread to normal surrounding breast tissue but are still contained in a small area. Stage 1 is divided into two subcategories.
The tumour is 2 cm or smaller and has not spread to lymph nodes.
A small number of cancer cells are found in the lymph nodes. Each lymph node with cancer cells in it is no larger than 2 mm.
Stage 2 breast cancer
Stage 2 describes cancer that is in a limited region of the breast but has grown larger. It reflects how many lymph nodes may contain cancer cells. This stage is divided into two subcategories.
Tumor <2cm with 1-3 axillary lymph nodes or tumor >2cm but upto 5cm without spread to lymph nodes.
The cancer has also spread to 1 to 3 axillary lymph nodes with tumor size >2cm but upto 5cm.
Stage 3 breast cancer
In stage 3 breast cancer, the cancer has spread further into the breast or the tumour is a larger size than earlier stages. It is divided into three subcategories.
Tumor size of more than 5cm with 1 to 3 axillary lymph nodes. Also included are tumor of any size if cancer cells are found in 4 to 9 axillary lymph nodes, or in lymph nodes around the breast bone (internal mammary lymph nodes) but not in axillary lymph nodes.
Tumor of any size involving either muscles of chest or skin of breast; may also have spread to axillary or internal mammary nodes but not both.
It is stage 3C when any of the following applies:
- The cancer has spread to 10 or more axillary lymph nodes or to lymph nodes below the collarbone (infraclavicular lymph nodes).
- The cancer has spread to more than 3 axillary lymph nodes and internal mammary lymph nodes.
- The cancer has spread to lymph nodes above the collarbone (supraclavicular lymph nodes).
Stage 4 breast cancer
The cancer has spread to other parts of the body (called distant metastasis), such as to the bone, liver, lungs or brain. This is also called metastatic breast cancer.
Recurrent breast cancer
Recurrent breast cancer means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it’s called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.