Stages of Breast Cancer

To plan a woman's treatment, the 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 to learn whether the cancer has spread and, if so, to what parts of the body. When breast cancer spreads, cancer cells are often found in lymph nodes under the arm (axillary lymph nodes). The extent of the cancer often is not known until after surgery to remove the tumor in the breast and the lymph nodes under the arm.

Stages of Breast Cancer

Doctors describe breast cancer by the following stages:

• Stage 0 is called carcinoma in situ.
  • Lobular carcinoma in situ (LCIS) refers to abnormal cells in the lining of a lobule. (See picture of lobule in the Background section.) These abnormal cells are a marker of increased risk. That means a woman with LCIS has an increased risk of developing invasive cancer in either breast sometime in the future. (Both breasts are at risk.)
  • Ductal carcinoma in situ (DCIS) is a precancerous condition in the lining of a duct. DCIS is also called intraductal carcinoma. The abnormal cells have not spread outside the duct to invade the surrounding breast tissue. However, if not treated, DCIS sometimes becomes invasive cancer.

  
  

  This picture shows ductal carcinoma in situ.

• Stage I is an early stage of invasive breast cancer. Stage I means that the tumor is no more than 2 centimeters (less than three-quarters of an inch) across, and cancer cells have not spread beyond the breast.

  This picture shows cancer that has spread outside the duct and has invaded nearby breast tissue.

• Stage II is one of the following:
  • The tumor in the breast is no more than 2 centimeters (less than three-quarters of an inch) across, and the cancer has spread to the lymph nodes under the arm; or
  • The tumor is between 2 and 5 centimeters (three-quarters of an inch to 2 inches), and the cancer may have spread to the lymph nodes under the arm; or
  • The tumor is larger than 5 centimeters (2 inches) but 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 means the tumor in the breast is smaller than 5 centimeters, the cancer has spread to the underarm lymph nodes, and the lymph nodes are attached to each other or to other structures. Or the tumor is large (more than 5 centimeters across), and the cancer has spread to the underarm lymph nodes.
• Stage IIIB means the tumor may have grown into the chest wall or the skin of the breast; or the cancer has spread to lymph nodes under the breastbone.
  

  Inflammatory breast cancer is a type of Stage IIIB breast cancer. It is rare. The breast looks red and swollen (or inflamed) because cancer cells block the lymph vessels in the skin of the breast.

• Stage IIIC means the cancer has spread to the lymph nodes under the breastbone and under the arm, or to the lymph nodes under or above the collarbone. The primary breast tumor may be of any size.
• 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 treatment. It may recur locally (in the breast or chest wall) or in any other part of the body (such as bone, liver, or lungs).

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