Question About Staging

Stage I

Stage I describes invasive breast cancer (cancer cells are breaking through to or invading normal surrounding breast tissue) Stage I is divided into subcategories known as IA and IB.

Stage IA describes invasive breast cancer in which:

• the tumor measures up to 2 centimeters AND
• the cancer has not spread outside the breast; no lymph nodes are involved

Stage IB describes invasive breast cancer in which:

• there is no tumor in the breast; instead, small groups of cancer cells – larger than 0.2 millimeter but not larger than 2 millimeters – are found in the lymph nodes OR
• there is a tumor in the breast that is no larger than 2 centimeters, and there are small groups of cancer cells – larger than 0.2 millimeter but not larger than 2 millimeters – in the lymph nodes

Microscopic invasion is possible in stage I breast cancer. In microscopic invasion, the cancer cells have just started to invade the tissue outside the lining of the duct or lobule, but the invading cancer cells can't measure more than 1 millimeter.

Learn about what treatments you can generally expect for stage IA and IB in the Options by Cancer Stage: Stage IA and IB page in Planning Your Treatment.

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Stage II

Stage II is divided into subcategories known as IIA and IIB.

Stage IIA describes invasive breast cancer in which:

• no tumor can be found in the breast, but cancer (larger than 2 millimeters) is found in 1 to 3 axillary lymph nodes (the lymph nodes under the arm) or in the lymph nodes near the breast bone (found during a sentinel node biopsy) OR
• the tumor measures 2 centimeters or smaller and has spread to the axillary lymph nodes OR
• the tumor is larger than 2 centimeters but not larger than 5 centimeters and has not spread to the axillary lymph nodes

Stage IIB describes invasive breast cancer in which:

• the tumor is larger than 2 centimeters but no larger than 5 centimeters; small groups of breast cancer cells -- larger than 0.2 millimeter but not larger than 2 millimeters -- are found in the lymph nodes OR
• the tumor is larger than 2 centimeters but no larger than 5 centimeters; cancer has spread to 1 to 3 axillary lymph nodes or to lymph nodes near the breastbone (found during a sentinel node biopsy) OR
• the tumor is larger than 5 centimeters but has not spread to the axillary lymph nodes

Learn about what treatments you can generally expect for stage IIA and IIB in the Options by Cancer Stage: Stage IIA and IIB page in Planning Your Treatment.

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Stage III

Stage III is divided into subcategories known as IIIA, IIIB, and IIIC.

Stage IIIA describes invasive breast cancer in which either:

• no tumor is found in the breast or the tumor may be any size; cancer is found in 4 to 9 axillary lymph nodes or in the lymph nodes near the breastbone (found during imaging tests or a physical exam) OR
• the tumor is larger than 5 centimeters; small groups of breast cancer cells (larger than 0.2 millimeter but not larger than 2 millimeters) are found in the lymph nodes OR
• the tumor is larger than 5 centimeters; cancer has spread to 1 to 3 axillary lymph nodes or to the lymph nodes near the breastbone (found during a sentinel lymph node biopsy)

Stage IIIB describes invasive breast cancer in which:

• the tumor may be any size and has spread to the chest wall and/or skin of the breast and caused swelling or an ulcer AND
• may have spread to up to 9 axillary lymph nodes OR
• may have spread to lymph nodes near the breastbone

Inflammatory breast cancer is considered at least stage IIIB. Typical features of inflammatory breast cancer include:

• reddening of a large portion of the breast skin
• the breast feels warm and may be swollen
• cancer cells have spread to the lymph nodes and may be found in the skin

Stage IIIC describes invasive breast cancer in which:

• there may be no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast AND
• the cancer has spread to 10 or more axillary lymph nodes OR
• the cancer has spread to lymph nodes above or below the collarbone OR
• the cancer has spread to axillary lymph nodes or to lymph nodes near the breastbone

Learn about what treatments you can generally expect for stage IIIA and operable IIIC in the Options by Cancer Stage: Stage IIIA and Operable IIIC page in Planning Your Treatment.

Learn about what treatments you can generally expect for stage IIIB and inoperable IIIC in the Options by Cancer Stage: Stage IIIB and Inoperable IIIC page in Planning Your Treatment.

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Stage IV

Stage IV describes invasive breast cancer that has spread beyond the breast and nearby lymph nodes to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver, or brain.

You may hear the words "advanced" and "metastatic" used to describe stage IV breast cancer. Cancer may be stage IV at first diagnosis or it can be a recurrence of a previous breast cancer that has spread to other parts of the body.

Learn about what treatments you can generally expect for stage IV in the Options by Cancer Stage: Stage IV section in Planning Your Treatment.