Lymph node status shows whether or not the lymph nodes in the armpit (axillary lymph nodes) contain cancer:
- Lymph node-negative means the lymph nodes do not contain cancer.
- Lymph node-positive means the lymph nodes contain cancer.
To view the location of lymph nodes, see Figure 4.4.
How is lymph node status assessed?
A physical exam (also called a clinical exam) can give a first estimate of lymph node status. Enlarged nodes can be a sign of cancer spread. However, a pathology exam is the best way to assess lymph node status.
Usually, a surgeon removes some lymph nodes in the armpit (axillary lymph nodes) with a technique called sentinel node biopsy. Then, a pathologist studies these nodes under a microscope. The results of a pathology exam help determine breast cancer stage and help plan treatment.
Learn more about sentinel node biopsy.
Pathology techniques
The most common technique for a pathology exam is H&E staining. Sometimes immunohistochemistry (IHC) is used to look for cancer after a sentinel node biopsy. And, at some centers, lymph nodes are tested with a technique called reverse transcription polymerase chain reaction (RT-PCR) to look for RNA in cancer cells.
However, whether IHC and RT-PCR are useful in prognosis is still under study.
Number of lymph nodes with cancer
One of the most important findings from a pathologic exam is lymph node status. Prognosis is poorer when cancer has spread to the lymph nodes (lymph node-positive). The more lymph nodes that contain cancer, the poorer prognosis tends to be [6].
The number of positive nodes guides treatment and predicts chances for long-term survival.
Pathologic lymph node status
See Figure 4.7 for an expanded version of this table that includes all subcategories.
To view the location of lymph nodes, see Figure 4.4.
pNX:
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Axillary lymph nodes cannot be assessed (for example, they were not removed during surgery)
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pN0:
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Axillary lymph nodes do not have cancer, however, some small groups of cancer cells (called micrometastases) may still be found using other tests, like IHC)
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pN1:
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Micrometasases OR
1–3 axillary lymph nodes have cancer AND/OR
Internal mammary nodes have tiny cancer cells found on sentinel node biopsy
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pN2:
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4–9 axillary lymph nodes have cancer OR
Internal mammary nodes have cancer that could be felt during a physical exam or could be seen on a mammogram
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pN3:
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10 or more axillary lymph nodes have cancer OR
infraclavicular (under the clavicle) nodes have cancer OR
Internal mammary nodes have cancer could be felt during a physical exam or could be seen on a mammogram plus 1 or more cancerous axillary nodes OR
Internal mammary nodes have tiny cancer cells plus 3 or more axillary lymph nodes have cancer OR
Supraclavicular (above the clavicle) nodes have cancer
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| Adapted from National Cancer Institute materials [79]. |
Clinical lymph node status (only used when pathologic findings are not available)
See Figure 4.7 for an expanded version of this table that includes all subcategories.
To view the location of lymph nodes, see Figure 4.4.
NX:
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Axillary lymph nodes cannot be assessed (for example, they have been removed in the past)
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N0:
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Axillary lymph nodes do not have cancer
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N1:
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Axillary lymph nodes have cancer, but can be moved around
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N2
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Axillary lymph nodes have cancer and are attached (matted) together or fixed to other structures, like the chest wall, OR
Internal mammary nodes have cancer, but axillary lymph nodes do not appear to have cancer
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N3:
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Infraclavicular (under the clavicle) nodes have cancer OR
Internal mammary nodes and axillary lymph nodes have cancer OR
Supraclavicular (above the clavicle) nodes have cancer
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| Adapted from National Cancer Institute materials [79]. |
Updated 10/24/11
