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Breast Cancer Treatment (PDQ®)

Patient Version
Last Modified: 04/09/2014

Stages of Breast Cancer



After breast cancer has been diagnosed, tests are done to find out if cancer cells have spread within the breast or to other parts of the body.

The process used to find out whether the cancer has spread within the breast or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. The following tests and procedures may be used in the staging process:

  • Sentinel lymph node biopsy : The removal of the sentinel lymph node during surgery. The sentinel lymph node is the first lymph node to receive lymphatic drainage from a tumor. It is the first lymph node the cancer is likely to spread to from the tumor. A radioactive substance and/or blue dye is injected near the tumor. The substance or dye flows through the lymph ducts to the lymph nodes. The first lymph node to receive the substance or dye is removed. A pathologist views the tissue under a microscope to look for cancer cells. If cancer cells are not found, it may not be necessary to remove more lymph nodes.

  • Chest x-ray : An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.

  • CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

  • Bone scan : A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.

  • PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.

There are three ways that cancer spreads in the body.

Cancer can spread through tissue, the lymph system, and the blood:

  • Tissue. The cancer spreads from where it began by growing into nearby areas.
  • Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
  • Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.

Cancer may spread from where it began to other parts of the body.

When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.

  • Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
  • Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.

The metastatic tumor is the same type of cancer as the primary tumor. For example, if breast cancer spreads to the bone, the cancer cells in the bone are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following stages are used for breast cancer:

This section describes the stages of breast cancer. The breast cancer stage is based on the results of testing that is done on the tumor and lymph nodes removed during surgery and other tests.

Stage 0 (carcinoma in situ)

There are 3 types of breast carcinoma in situ:

Stage I

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Stage I breast cancer. Drawing shows stage IA on the left; the tumor is 2 cm or smaller and has not spread outside the breast. Drawings in the middle and on the right show stage IB. In the drawing in the middle, no tumor is found in the breast, but small clusters of cancer cells are found in the lymph nodes. In the drawing on the right, the tumor is 2 cm or smaller and small clusters of cancer cells are found in the lymph nodes.
Stage I breast cancer. In stage IA, the tumor is 2 centimeters or smaller and has not spread outside the breast. In stage IB, no tumor is found in the breast or the tumor is 2 centimeters or smaller. Small clusters of cancer cells (larger than 0.2 millimeter but not larger than 2 millimeters) are found in the lymph nodes.

In stage I, cancer has formed. Stage I is divided into stages IA and IB.

Stage II

Stage II is divided into stages IIA and IIB.

  • In stage IIA:
    Enlarge
    Stage IIA breast cancer. Drawing on the left shows no tumor in the breast, but cancer is found in 3 axillary lymph nodes. Drawing in the middle shows the tumor size is 2 cm or smaller and cancer is found in 3 axillary lymph nodes. Drawing on the right shows the tumor is larger than 2 cm but not larger than 5 cm and has not spread to the lymph nodes.
    Stage IIA breast cancer. No tumor is found in the breast and cancer is found in 1 to 3 axillary lymph nodes or lymph nodes near the breastbone (left panel); OR the tumor is 2 centimeters or smaller and cancer is found in 1 to 3 axillary lymph nodes or lymph nodes near the breastbone (middle panel); OR the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the lymph nodes (right panel).
  • In stage IIB, the tumor is:
    Enlarge
    Stage IIB breast cancer. The drawing on the left shows the tumor is larger than 2 cm but not larger than 5 cm and small clusters of cancer cells are in the lymph nodes. The drawing in the middle shows the tumor is larger than 2 cm but not larger than 5 cm and cancer is in 3 axillary lymph nodes. The drawing on the right shows the tumor is larger than 5 cm but has not spread to the lymph nodes.
    Stage IIB breast cancer. The tumor is larger than 2 centimeters but not larger than 5 centimeters and small clusters of cancer cells (larger than 0.2 millimeter but not larger than 2 millimeters) are found in the lymph nodes (left panel); OR the tumor is larger than 2 centimeters but not larger than 5 centimeters and cancer is found in 1 to 3 axillary lymph nodes or lymph nodes near the breastbone (middle panel); OR the tumor is larger than 5 centimeters and has not spread to the lymph nodes (right panel).

Stage IIIA

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Stage IIIA breast cancer. The drawing on the left shows no tumor in the breast; cancer is found in 8 axillary lymph nodes. The drawing in the middle shows the tumor is larger than 5 cm and small clusters of cancer cells are in the lymph nodes. The drawing on the right shows the tumor is larger than 5 cm and cancer is in 3 axillary lymph nodes.
Stage IIIA breast cancer. No tumor is found in the breast or the tumor may be any size and cancer is found in 4 to 9 axillary lymph nodes or lymph nodes near the breastbone (left panel); OR the tumor is larger than 5 centimeters and small clusters of cancer cells (larger than 0.2 millimeter but not larger than 2 millimeters) are found in the lymph nodes (middle panel); OR the tumor is larger than 5 centimeters and cancer is found in 1 to 3 axillary lymph nodes or lymph nodes near the breastbone (right panel).

In stage IIIA:

Stage IIIB

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Stage IIIB breast cancer. The drawing on the left is a cross section of the breast showing  that cancer has spread to the chest wall. The ribs, muscle, and fatty tissue are also shown. The drawing on the right shows the tumor has spread to the skin of the breast. An inset shows inflammatory breast cancer.
Stage IIIB breast cancer. The tumor may be any size and cancer has spread to the chest wall and/or to the skin of the breast and caused swelling or an ulcer. Cancer may have spread to up to 9 axillary lymph nodes or the lymph nodes near the breastbone. Cancer that has spread to the skin of the breast may be inflammatory breast cancer.

In stage IIIB, the tumor may be any size and cancer has spread to the chest wall and/or to the skin of the breast and caused swelling or an ulcer. Also, cancer may have spread to:

Cancer that has spread to the skin of the breast may also be inflammatory breast cancer. See the section on Inflammatory Breast Cancer for more information.

Stage IIIC

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Stage IIIC breast cancer. The drawing on the left shows cancer in lymph nodes in the axilla. The drawing in the middle shows cancer in lymph nodes above the collarbone. The drawing on the right shows cancer in lymph nodes in the axilla and in lymph nodes near the breastbone.
Stage IIIC breast cancer. No tumor is found in the breast or the tumor may be any size and may have spread to the chest wall and/or to the skin of the breast and caused swelling or an ulcer. Also, cancer has spread to 10 or more axillary lymph nodes (left panel); OR to lymph nodes above or below the collarbone (middle panel); OR to axillary lymph nodes and lymph nodes near the breastbone (right panel). Cancer that has spread to the skin of the breast may be inflammatory breast cancer.

In stage IIIC, no tumor is found in the breast or the tumor may be any size. Cancer may have spread to the skin of the breast and caused swelling or an ulcer and/or has spread to the chest wall. Also, cancer has spread to:

Cancer that has spread to the skin of the breast may also be inflammatory breast cancer. See the section on Inflammatory Breast Cancer for more information.

For treatment, stage IIIC breast cancer is divided into operable and inoperable stage IIIC.

Stage IV

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Stage IV breast cancer. Drawing shows cancer has spread from lymph nodes through the blood to other parts of the body, such as the brain, lungs, liver, and bone.
Stage IV breast cancer. The cancer has spread to other parts of the body, most often the bones, lungs, liver, or brain.

In stage IV, cancer has spread to other organs of the body, most often the bones, lungs, liver, or brain.