What Are the Stages of Breast Cancer?

Staging is a way of describing a cancer. Knowing your cancer stage will help you and your health care team decide what kind of treatment is best for you. Early stage cancer is considered to be Stages I and II. Late stage cancer is considered to be Stages III and IV. The treatment choices will depend on:

  • How small or large your tumor is,
  • If cancer is found in the lymph nodes in your armpit, and
  • If cancer is found in other parts of your body.

About Lymph Nodes

  • Lymph nodes are small, bean-shaped structures found throughout your body.
  • Lymph nodes are part of your body's immune system.
  • Lymph nodes act as filters or traps for germs or cancer cells and help fight off infection and disease.
  • Sometimes cancer cells enter the lymph nodes, which is why doctors will look at your lymph nodes when they are staging your cancer.

What Are Axillary Nodes?

  • Axillary nodes are the lymph nodes in your armpit.
  • When breast cancer spreads outside the breast, it usually spreads first to the axillary nodes.
  • Finding out whether or not cancer has spread to the axillary nodes (axillary node dissection) is important to figure out the stage of cancer and the type of treatment needed.
Stages of Breast Cancer (From the Web site of the National Cancer Institute www.cancer.gov)
Stage 0

In situ cancer (also called preinvasive or noninvasive cancer).

Abnormal cells have been found in the lining of the breast ducts (Ductal carcinoma in situ) and have not spread outside the duct to other tissues in the breast. OR

Abnormal cells have been found in the lobules of the breast (Lobular carcinoma in situ).

Stage I

Cancer has formed. The tumor is 2 cm* (1 inch) or smaller, and cancer has NOT spread to the lymph nodes or outside the breast.

Stage IIA

No tumor is found in the breast, but is found in the axillary lymph nodes (lymph nodes in the armpit); OR

The tumor is 2 cm* (1 inch) or smaller and cancer HAS spread to the lymph nodes in the armpit; OR

The tumor is between 2 and 5 cm*(1 and 2 inches), but cancer has NOT spread to the axillary lymph nodes.

Stage IIB

The tumor is between 2 and 5 cm* (1 and 2 inches) and cancer HAS spread to the lymph nodes in the armpit; OR

The tumor is larger than 5 cm* (2 inches), but cancer has NOT spread to the axillary lymph nodes.

Stage IIIA

No tumor is found in the breast, but cancer is found in the axillary lymph nodes, or in the lymph nodes near the breast bone; OR

The tumor is 2 cm* (1 inch) or smaller and cancer has spread to axillary nodes or cancer may have spread to the lymph nodes near the breast bone; OR

The tumor is between 2 and 5 cm* (1 and 2 inches) and cancer has spread to the axillary lymph nodes, or cancer may have spread to the lymph nodes near the breast bone; OR

The tumor is larger than 5 cm* and cancer has spread to the axillary lymph nodes, or cancer may have spread to the lymph nodes near the breast bone.

Stage IIIB

The tumor may be any size and:

Cancer has spread to the chest wall and/or the skin of the breast; and

Cancer may have spread to the axillary lymph nodes or to lymph nodes near the breastbone.

Cancer that has spread to the skin of the breast is inflammatory breast cancer **. Inflammatory breast cancer is considered at least stage IIIB.

Stage IIIC

There may be no sign of cancer in the breast, or the tumor may be any size and may have spread to the chest wall and/or the skin of the breast. Also, cancer has spread to the lymph nodes above or below the collarbone and may have spread to the axillary lymph nodes or to lymph nodes near the breastbone.

The cancer is either operable or inoperable. In the operable stage, the cancer:

  • Is found in ten or more axillary lymph nodes; or
  • Is found in lymph nodes below the collarbone; or
  • Is found in axillary lymph nodes and in lymph nodes near the breastbone.

In the inoperable stage, the cancer has spread to the lymph nodes above the collarbone.

Stage IV

The tumor HAS spread to other organs of the body, most often the bones, lungs, liver or brain.

*Cm means centimeters. One inch is about 2.5 centimeters. Inches listed above are not exact measurements. Because of varying settings on computers, this graphic may not be to scale.

Circular diagragm of 1, 2, 3, 4, 5 centimeters

**For more information about inflammatory breast cancer, visit: www.mayoclinic.com/health/inflammatory-breast-cancer/DS00632


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