Breast Cancer Stages

If you are diagnosed with breast cancer, we will perform necessary tests to find out if the cancer has spread from the breast to other parts of the body. This is called staging and is an important step toward planning a treatment program.

As defined by the American Joint Committee on Cancer, stages of breast cancer are defined by the size of the tumor (T), whether cancer has spread to one or more lymph nodes (N) or distant organs (M).

Carcinoma in situ or Stage 0

This is the earliest stage of breast cancer and includes ductal carcinoma in situ or DCIS. Although lobular carcinoma in situ (LCIS) is also included, LCIS is not considered a breast cancer and does not require treatment. LCIS is considered a marker for increased risk for breast cancer development in either breast and not just in the breast in which it was found. LCIS is not a precancerous lesion but a high risk lesion.

Paget’s disease of the nipple is also stage 0 if no invasive tumor is present.

Stage 1

This stage is divided into 1A and 1B.

  • Stage 1A means your tumor is 2 centimeters (about ¾ of an inch) or less across, and cancer is not found in any lymph nodes or distant sites.
  • Stage 1B means your tumor is 2 centimeters (about ¾ of an inch) or less across and small amounts of cancer have spread to the lymph nodes under your arm but not to any other sites.

Stage 2

This stage is divided into 2A and 2B.

  • Stage 2A means the tumor is 2 centimeters (3/4 of an inch) or less across, and there is cancer in 1 to 3 lymph nodes under the arm, has spread in very small amounts to the internal mammary lymph nodes, has spread to both the underarm lymph nodes and the mammary lymph nodes, or the cancer is between 2 and 5 centimeters (3/4 to 2 inches) and hasn’t spread to any lymph nodes.
  • Stage 2B means your tumor is between 2 and 5 centimeters (3/4 of an inch to 2 inches) and has spread to the underarm lymph nodes and/or very small amounts have been found in the internal mammary lymph nodes, or the cancer is larger than 5 centimeters (larger than 2 inches) but hasn’t spread.

Stage 3

This stage is divided in 3A, 3B and 3C.

  • Stage 3A means you have a tumor that is less than 5 centimeters (2 inches) and may not even be in the breast. However, cancer is in between four to nine lymph nodes under your arm and has spread to the internal mammary lymph nodes, or the tumor is larger than 5 centimeters and has spread to the lymph nodes but not to the chest wall.
  • Stage 3B means your cancer has spread to tissues near the breast (the skin or chest wall, including your ribs and chest muscles) but not into any lymph nodes, or the cancer has spread to tissues near the breast and to one to three underarm lymph nodes and small amounts have been found in the internal mammary lymph nodes, or the cancer has spread to four to nine underarm lymph nodes.
  • Stage 3C can be a tumor of any size and is defined by cancer that has spread to the lymph nodes under or above the collarbone and near the neck, your cancer has spread to 10 or more underarm lymph nodes, or cancer has spread to lymph nodes and enlarged the internal mammary lymph nodes, or the cancer is in four or more lymph nodes under the arm and very small amounts have been found in the internal mammary lymph nodes. Inflammatory breast cancer is Stage 3B or 3C.

 

Stage 4

This stage is defined as the cancer having spread to other organs of the body, most often the bones, lungs, liver or brain, or the tumor has spread to lymph nodes far from the breast.

Inflammatory breast cancer
This is a very rare type of cancer. Your breast looks red and inflamed and feels warm to the touch. The skin around the breast shows signs of ridges; it may have a pitted appearance. It’s considered stage 3B unless it has spread to distant lymph nodes or organs. If that’s the case, you may be a stage 4.

Recurrent
This stage means that your cancer has come back after treatment. Recurrent breast cancer may come back in the breast but it may also come back in the chest or in another part of the body.