To plan your treatment, your doctor needs to know the extent (stage) of the disease. The stage is based on the size of the tumor and whether the cancer has spread. Staging may involve x-rays and lab tests. These tests can show whether the cancer has spread and, if so, to what parts of your body. When breast cancer spreads, cancer cells are often found in lymph nodes under the arm (axillary lymph nodes). The stage often is not known until after surgery to remove the tumor in your breast and the lymph nodes under your arm.
These are the stages of breast cancer:
Stage 0 is carcinoma in situ.
(1) Lobular carcinoma in situ (LCIS): Abnormal cells are in
the lining of a lobule. LCIS seldom becomes invasive cancer.
However, having LCIS in one breast increases the risk of
cancer for both breasts.
(2) Ductal carcinoma in situ (DCIS): Abnormal cells are in the
lining of a duct. DCIS is also called intraductal carcinoma.
This picture shows ductal carcinoma in situ.
The abnormal cells have not spread outside the duct. They
have not invaded the nearby breast tissue. DCIS sometimes
becomes invasive cancer if not treated.
Stage I is an early stage of invasive breast cancer.
The tumor is no more than 2 centimeters
(three-quarters of an inch) across. Cancer cells have not
spread beyond the breast.
This picture shows cancer cells spreading outside the duct.
The cancer cells are invading nearby tissue inside the breast.
Stage II is one of the following:
- The tumor in the breast is no more than 2 centimeters (three-quarters of an inch) across. The cancer has spread to the lymph nodes under the arm.
- The tumor is between 2 and 5 centimeters (three-quarters of an inch to 2 inches). The cancer may have spread to the lymph nodes under the arm.
- The tumor is larger than 5 centimeters (2 inches). The cancer has not spread to the lymph nodes under the arm.
Stage III may be a large tumor, but the cancer has not spread beyond the breast and nearby lymph nodes. It is locally advanced cancer.
Stage IIIA is one of the following:
- The tumor in the breast is smaller than 5 centimeters (2 inches). The cancer has spread to underarm lymph nodes that are attached to each other or to other structures.
- The tumor is more than 5 centimeters across. The cancer has spread to the underarm lymph nodes.
Stage IIIB is one of the following:
- The tumor has grown into the chest wall or the skin of the breast and to lymph nodes behind the breastbone.
- Inflammatory breast cancer is a rare type of Stage IIIB breast cancer. The breast looks red and swollen because cancer cells block the lymph vessels in the skin of the breast.
Stage IIIC is a tumor of any size. It has spread in one of the following ways:
- The cancer has spread to the lymph nodes behind the breastbone and under the arm.
- The cancer has spread to the lymph nodes under or above the collarbone.
Stage IV is distant metastatic cancer.
The cancer has spread to other parts of the body.
Recurrent cancer is cancer that has come back (recurred) after a period of time when it could not be detected. It may recur locally in the breast or chest wall. Or it may recur in any other part of the body, such as the bone, liver, or lungs.
