Lymph Node Dissection in Breast Cancer

Once you've been diagnosed with breast cancer, your oncologist will need to determine if cancer cells have spread to your lymph nodes by removing, or dissecting, some of the nodes and looking at them under a microscope.

Lymph nodes are present throughout your body and work as filters where bacteria, viruses, or cancer cells are caught. The nodes work with your circulating blood to provide nutrients to all your cells, as well as remove cellular waste products. Cancer cells present in the lymph nodes near your breast and arm have the potential to spread, or metastasize, to other areas of your body, increasing your risk of metastatic breast cancer.

Types of Lymph Node Dissection

Lymph nodes may be removed during breast surgery or in a separate procedure. Here are the two different types of lymph node dissection:

Sentinel Lymph Node Biopsy (SLNB)

This is a diagnostic procedure done to remove a small sample of lymph nodes into which cancer may be draining. Sentinel nodes are the first nodes to which cancer cells must travel before going any further. A blue dye and a weak radioactive agent will be injected into the breast tumor. Lymphatic vessels carry these substances along the same path that cancer cells would likely take. The first lymph node(s) the dye or radioactive substance travels to will be the sentinel node(s). This procedure removes the least number of lymph nodes.

Axillary Lymph Node Dissection (ALND)

If cancer is found during your sentinel node biopsy, your surgeon may remove some, or all, of your axillary lymph nodes, which are those in the area of your armpit.

Axillary lymph node dissection may be done as part of a lumpectomy or mastectomy. As few as 10 or as many as 40 lymph nodes may be removed for testing. These will be sent to the pathology lab where they will be carefully examined for cancer cells.

Your pathology report will say how many nodes were removed and how many of them, if any, contained cancer cells. This important information affects the staging of your cancer and influences your treatment options.

How Lymph Node Status Affects Treatment

Lymph node dissection is an important part of your complete diagnosis and staging.

Clear nodes and a small tumor will require less treatment because the chance of metastasis is low, while a larger tumor and/or positive nodes may be followed up with chemotherapy, radiation, or both.

Based on the number of positive nodes, your lymph node involvement will be given a rating from N0 to N3.

Understanding Lymph Node Status
Lymph node rating Meaning
N0 Negative, or clean: Nodes contain no cancer or micrometastases.
N1 Positive: Cancer is found in 1 to 3 lymph nodes under the arm or in the breast.
N2 Positive: Cancer is found in 4 to 9 lymph nodes under the arm or in the breast.
N3 PositiveCancer is found in 10 or more lymph nodes under the arm or has spread under or over the collarbone. It may have been found in the underarm nodes as well as lymph nodes within the breast.

Risks and Side Effects of Lymph Node Dissection

Side effects of lymph node removal may include loss of sensation in the breast or axilla, limited arm mobility, and muscle weakness. Women are typically recommended to avoid lifting heavy objects and unnecessarily straining the area.

The skin in the axillary area may be numb or less sensitive to touch after surgery because nerves may have been damaged during the procedure. Arm and shoulder range of motion may be affected, so be sure to ask for physical therapy to help regain your motion and strength.

The most common side effect of a lymph node dissection is lymphedema, in which the arm swells, sometimes significantly. Since you'll have fewer lymph nodes under your arm to process lymphatic fluid, the fluid may build up and cause swelling along your arm and sometimes your hand.

If just a few nodes are removed, lymphedema may be a temporary condition, but if most of your lymph nodes were removed, it may be a long-lasting problem. Therapeutic massage and pressure garments can help with lymphedema.

A Word From Verywell

The extent of lymph node involvement is an important part of your breast cancer diagnosis and will provide key information for the next steps in your treatment plan.

Always check your underarm area during your monthly breast self-exam to keep tabs on your axillary lymph nodes, which are likely to swell if cancer is present.

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