There are five stages of breast cancer, starting at zero and going up to four. There are several variables within some stages. Tumors are measured in millimeters and centimeters (ten millimeters equals one centimeter). For consistency here, we measure tumors in millimeters.
Stage 0 breast cancer
-This is the very beginning of the scale. It describes noninvasive breast cancers or precancers. This includes the most common form of noninvasive cancer, called ductal carcinoma in situ (DCIS). Within stage 0, there is no evidence that cancer cells or other abnormal cells have invaded neighboring normal tissue.
- Stage 1 breast cancer
– Stage 1 describes a very early stage of invasive cancer. At this point, tumor cells have spread to normal surrounding breast tissue but are still contained in a small area. Stage I is divided into two subcategories:
In stage 1A, a tumor measures up to 20 millimeters (about the size of a grape), and there’s no cancer in the lymph nodes.
Stage 1B can be described as either:
-a small tumor in the breast that is less than 20 millimeters plus small clusters of cancer cells in the lymph nodes; or
-no tumor in the breast plus small clusters of cancer cells in the lymph nodes.
- 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.
Stage 2A is based on one of the following:
- Either there is no tumor in the breast or there is a breast tumor up to 20 millimeters (about the size of a grape), plus cancer has spread to the lymph nodes under the arm.
- A tumor of 20 to 50 millimeters is present in the breast, but cancer has not spread to the lymph nodes.
Stage 2B is based on one of these criteria:
- A tumor of 20 to 50 millimeters is present in the breast, along with cancer that has spread to between one and three nearby lymph nodes.
- A tumor in the breast is larger than 50 millimeters, but cancer has not spread to any lymph nodes.
- Stage 3 breast cancer
In stage 3 breast cancer, the cancer has spread further into the breast or the tumor is a larger size than earlier stages. It is divided into three subcategories.
Stage 3A is based on one of the following:
- With or without a tumor in the breast, cancer is found in four to nine nearby lymph nodes.
- A breast tumor is larger than 50 millimeters, and the cancer has spread to between one and three nearby lymph nodes.
In stage 3B, a tumor has spread to the chest wall behind the breast. In addition, these factors contribute to assigning this stage:
- Cancer may also have spread to the skin, causing swelling or inflammation.
- It may have broken through the skin, causing an ulcerated area or wound.
- It may have spread to as many as nine underarm (axillary) lymph nodes or to nodes near the breastbone.
In stage 3C, there may be a tumor of any size in the breast, or no tumor present at all. But either way, the cancer has spread to one of the following places:
- ten or more underarm (axillary) lymph nodes
- lymph nodes near the collarbone
- some underarm lymph nodes and lymph nodes near the breastbone
- the skin
- Stage 4 breast cancer
– Stage 4 is the most advanced stage of breast cancer. It has spread to nearby lymph nodes and to distant parts of the body beyond the breast. This means it possibly involves your organs — such as the lungs, liver, or brain — or your bones.
Breast cancer may be stage IV when it is first diagnosed, or it can be a recurrence of a previous breast cancer that has spread.