The Who, What, Where, When and Sometimes, Why.

Lymph Node Status and Staging

Lymph node status shows whether or not the lymph nodes in the underarm area (axillary lymph nodes) contain cancer:

  • Lymph node-negative means none of the axillary lymph nodes contain cancer.
  • Lymph node-positive means at least one axillary lymph node contains cancer.

Prognosis is better when cancer has not spread to the lymph nodes (lymph node-negative) [13].

The more lymph nodes that contain cancer, the poorer prognosis tends to be [13].

The number of positive nodes guides treatment and helps predict prognosis (chances for survival).

See Figure 4.4 for a drawing of the breast and lymph nodes.

Learn more about lymph node status.

Pathologic lymph node status

A pathology exam is the best way to assess lymph node status. This is called pathologic lymph node status.

Usually, a surgeon removes one or more axillary lymph nodes with a technique called sentinel node biopsy. Then, a pathologist studies these nodes under a microscope to see if they contain cancer.

These results help determine breast cancer stage and guide treatment.

Learn more about sentinel node biopsy and assessing lymph nodes.

Clinical lymph node status

A physical exam (also called a clinical exam) can give a first estimate of lymph node status. This is called clinical lymph node status. Enlarged nodes can be a sign the breast cancer has spread to the nodes.

Clinical lymph node status is only used when pathologic findings are not available.

Lymph node status categories

See Figure 4.4 for a drawing of the breast and lymph nodes.

 

Pathologic lymph node status

Clinical lymph node status
(only used when pathologic findings are not available) 

NX

Axillary and other nearby lymph nodes cannot be assessed (for example, they were not removed during surgery)

Axillary and other nearby lymph nodes cannot be assessed (for example, they were removed in the past)

N0

Axillary and other nearby lymph nodes do not have cancer or only have isolated tumor cells (individual cancer cells), when looked at under a microscope

Axillary and other nearby lymph nodes do not have cancer

N1

Micrometastases (very small clusters of cancer) OR

1–3 axillary lymph nodes have cancer AND/OR

Internal mammary nodes have cancer or micrometastases (very small clusters of cancer cells) found on sentinel node biopsy

Axillary lymph nodes have cancer, but can be moved around

N2

4–9 axillary lymph nodes have cancer OR

Internal mammary nodes have cancer, but axillary lymph nodes don’t have cancer

Axillary lymph nodes have cancer and are matted together or fixed to other structures (such as the chest wall) OR

Internal mammary nodes have cancer, but axillary lymph nodes don’t appear to have cancer

N3

10 or more axillary lymph nodes have cancer OR

Infraclavicular (under the clavicle) nodes have cancer OR

Internal mammary nodes have cancer plus 1 or more axillary lymph nodes have cancer OR

4 or more axillary lymph nodes have cancer plus internal mammary nodes have cancer or micrometastases found on sentinel node biopsy OR

Supraclavicular (above the clavicle) nodes have cancer

Infraclavicular (under the clavicle) nodes have cancer (axillary lymph nodes may or may not have cancer) OR

Internal mammary nodes and axillary lymph nodes have cancer OR

Supraclavicular (above the clavicle) nodes have cancer (axillary lymph nodes may or may not have cancer)

Adapted from American Joint Committee on Cancer materials [33].

Pathologic lymph node status

NX

Axillary and other nearby lymph nodes cannot be assessed (for example, they were not removed during surgery)

N0

Axillary and other nearby lymph nodes do not have cancer or only have isolated tumor cells (individual cancer cells), and when looked at under a microscope

 

Subcategories of N0

 

N0(i+)

Isolated tumor cells only (0.2 mm or smaller)

 

N0(mol+)

RT-PCR molecular testing is positive, but no isolated tumor cells are found

N1

Micrometastases (very small clusters of cancer cells) OR

1–3 axillary lymph nodes have cancer AND/OR

Internal mammary nodes have cancer or micrometastases found on sentinel node biopsy

 

Subcategories of N1

 

N1mi

Micrometastases are between 0.2 mm and 2 mm

 

N1a

1-3 axillary lymph nodes have cancer and at least one group of cancer cells is larger than 2 mm

 

N1b

Internal mammary nodes have cancer (not including isolated tumor cells) found with sentinel node biopsy

 

N1c

1-3 axillary lymph nodes have cancer and at least one group of cancer cells is larger than 2 mm AND

Internal mammary nodes have cancer (not including isolated tumor cells) found with sentinel node biopsy

N2

4–9 axillary lymph nodes have cancer OR

Internal mammary nodes have cancer seen on a mammogram or other imaging, but axillary lymph nodes don’t have cancer

 

Subcategories of N2

 

N2a

4–9 axillary lymph nodes have cancer and at least one group of cancer cells is larger than 2 mm

 

N2b

Internal mammary nodes have cancer that could be felt during a physical exam or seen on a mammogram or other imaging, but axillary lymph nodes don’t have cancer

N3

10 or more axillary lymph nodes have cancer OR

Infraclavicular (under the clavicle (collarbone)) nodes have cancer OR

Internal mammary nodes have cancer seen on a mammogram or other imaging plus 1 or more axillary lymph nodes have cancer OR

3 or more axillary lymph nodes have cancer plus internal mammary nodes have cancer or micrometastases found with sentinel node biopsy OR

Supraclavicular nodes have cancer

 

Subcategories of N3

 

N3a

10 or more axillary lymph nodes have cancer (at least one group of cancer cells is larger than 2 mm) OR

Infraclavicular nodes have cancer

 

N3b

1-9 axillary lymph nodes have cancer and at least one group of cancer cells is larger than 2 mm, plus internal mammary nodes have cancer seen on a mammogram or other imaging OR

4–9 axillary lymph nodes have cancer and at least one group of cancer cells is larger than 2 mm, plus internal mammary nodes have cancer (not including isolated cancer cells) found with sentinel node biopsy
 

N3c

Supraclavicular (above the clavicle) nodes have cancer

Adapted from American Joint Commission on Cancer materials [33].

 Updated 12/17/20

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