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.
See Figure 4.4 for an illustration of the breast and lymph nodes.
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.
Some centers use immunohistochemistry (IHC) and/or reverse transcription polymerase chain reaction (RT-PCR) to look for cancer in the sentinel lymph node(s) after a sentinel node biopsy. Findings from two recent studies suggest the small deposits of tumor cells in sentinel lymph nodes identified by IHC are not clinically useful in prognosis [85-86]. As a result, many centers no longer use IHC to test sentinel lymph nodes [87]. At this time, there is no proven role for RT-PCR in prognosis. This test should only be used in a research setting.
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 the prognosis tends to be [6].
The number of positive nodes guides treatment and predicts the chances for long-term survival.
Pathologic lymph node status
See Figure 4.7 for an expanded version of this table that includes all subcategories.
See Figure 4.4 for an illustration of the breast and lymph nodes.
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 and other nearby lymph nodes do not have cancer (when looked at under a microscope)
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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 amounts of cancer 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, but axillary lymph nodes do not have cancer
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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 axillary lymph nodes have cancer OR
3 or more axillary lymph nodes have cancer and internal mammary nodes have cancer or tiny cancer cells found on sentinel node biopsy OR
Supraclavicular (above the clavicle) nodes have cancer
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Adapted from National Cancer Institute materials [84].
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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.
See Figure 4.4 for an illustration of the breast and lymph nodes.
NX:
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Axillary and other nearby lymph nodes cannot be assessed (for example, they have been removed in the past)
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N0:
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Axillary and other nearby 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 (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)
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Adapted from National Cancer Institute materials [84].
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Updated 10/29/12
