Lymph node surgery

If you have invasive breast cancer, your surgeon may recommend removing some nearby lymph nodes under your arm to check for cancer spread. Lymph nodes are tiny glands that filter waste and help the body fight infection.

This surgery often takes place at the same time as your breast surgery to remove cancer. The results give your care team important information about the stage of the cancer and the treatment plan that’s right for you.

What are lymph nodes?

Your body has a network called the lymphatic system, made up of vessels and lymph nodes. This system helps fight infection and manage fluids. The lymph nodes in this network act as small filters that trap waste, bacteria, and sometimes, cancer cells.

How does the lymphatic system relate to breast cancer?

In some cases, breast cancer spreads outside of the breast through the lymphatic system. This is why lymph nodes are an important part of diagnosing and staging breast cancer. The axillary lymph nodes, located in the armpit, are often the first lymph nodes where breast cancer spreads.

Cancer in the axillary nodes means the cancer has spread beyond the original breast tumor. This information helps doctors stage the cancer and plan your treatment.

Over the last 40 years, one of the biggest areas of research and change in breast cancer surgery is how doctors approach the need for axillary surgery and what type of axillary surgery is recommended.

If cancer is found in the lymph nodes, your care team may recommend treatments such as:

• Radiation therapy to the breast or underarm
• Chemotherapy to treat any cancer cells that may have spread beyond the breast
• Hormonal therapy, targeted therapy, or immunotherapy, depending on tumor biomarkers such as hormone-receptor or HER2 status

Sentinel lymph node biopsy

The sentinel lymph nodes are the first place breast cancer is likely to go. Usually, the sentinel nodes are axillary nodes under the arm, but not always. Other sentinel node locations can include the chest wall or behind the breastbone.

Doctors check these lymph nodes with a procedure called a sentinel lymphadenectomy, which is commonly called a sentinel lymph node biopsy. This is performed at the same time as lumpectomy or mastectomy surgery. If you are also having breast reconstruction, the biopsy is part of the same operation.

Here is how the sentinel lymph node biopsy works:

1. Before surgery, your doctor will inject a blue dye and/or a radioactive tracer into your breast.
2. The dye or tracer travels through the lymphatic channels to the sentinel nodes in the axilla (armpit).
3. During surgery, the surgeon will look for the lymph nodes that have taken up the dye or tracer, remove them, and send them to a lab.

Usually, doctors remove one to three lymph nodes during this procedure. If the sentinel nodes don’t have cancer, it is very unlikely the cancer has spread to other lymph nodes in the axilla.

Sentinel lymph node biopsy and lymphedema risk

Any time lymph nodes are removed, there is a risk of lymphedema, a swelling of the tissues under the skin that can become a chronic condition if not treated early.

Lymphedema can happen in the arm, hand, or breast on the same side where lymph nodes are removed. The risk increases when more lymph nodes are removed, but there is still some risk with removing a few nodes during a sentinel lymph node biopsy.

If sentinel node biopsy has been recommended for you, talk with your care team about risk reduction steps you can take.

Some cancer centers offer baseline arm measurements and monitoring technology, such as bioimpedance spectroscopy, which uses a low-level electrical current to confirm signs of lymphedema at a stage when it may be reversible. Learn more on the lymphedema page.

Axillary lymph node dissection

Axillary lymph node dissection is surgery that removes all of the lymph nodes under the arm. This is usually between 10-30 nodes. An axillary lymph node dissection will help your doctors stage the cancer and recommend adjuvant treatment (treatment after surgery).

In the past, everyone having surgery to remove breast cancer also had an axillary lymph node dissection. Now, many people with early-stage breast cancer have the option of sentinel lymph node removal instead. This limits the number of lymph nodes removed. Usually, this is about one to three lymph nodes.

Sentinel lymph node removal also causes fewer side effects, including a significantly lower risk of lymphedema. Still, there are times when axillary dissection is recommended.

Axillary dissection may be needed if:

• A previous sentinel lymph node biopsy shows cancer in three or more axillary lymph nodes.
• Swollen lymph nodes in the axilla (armpit) or collarbone can be felt before surgery or seen on imaging tests, and a fine needle aspiration or core needle biopsy confirms cancer.
• The sentinel lymph node biopsy is still positive for cancer cells after chemotherapy was given to shrink the tumor before surgery.
• You have inflammatory breast cancer.
• Imaging shows extensive cancer in the lymph nodes.

Doctors may not recommend axillary dissection if:

• There is no cancer in the lymph nodes
• There is cancer in only one or two lymph nodes on sentinel lymph node biopsy.

Axillary node dissection carries a higher risk of side effects. These include shoulder stiffness, loss of sensation to the upper arm (in the triceps area), and chronic lymphedema, a swelling that may cause discomfort or pain.

Managing axillary node dissection lymphedema risk

If lymphedema develops after underarm lymph node surgery, symptoms may occur in the hand, arm, trunk, or breast on the same side.

It’s important for you and your doctor to consider which type of lymph node removal surgery is right for your situation. This can help reduce the risk of unnecessarily removing too many lymph nodes (and increasing the risk of lymphedema).

There are also other ways to reduce the risk of lymphedema:

• As you are planning surgery with your doctor, ask about getting baseline arm measurements before the date of your operation. A baseline measurement helps your care team know what is normal for your arm size. This helps your team monitor for any changes after surgery.
• Tools such as bioimpedance spectroscopy can provide a baseline assessment and help detect lymphedema at an early stage, when it is potentially reversible.
• For people undergoing an axillary lymph node dissection, some cancer centers offer new surgical techniques to reduce the risk of lymphedema. These include lymphovenous bypass (sometimes called immediate lymphatic reconstruction). This procedure can be performed at the same time as axillary lymph node dissection. It requires specialized training, and it is not yet available at all cancer centers.

If lymphedema develops, your doctor may refer you to a physical or occupational therapist or a lymphedema specialist.

Learn more on the Lymphedema page.

Targeted axillary lymph node dissection

If imaging suggests cancer could be in an underarm lymph node, your doctor may recommend a core needle biopsy of the node.

If the biopsy confirms cancer, and your treatment plan includes neoadjuvant chemotherapy (chemotherapy given before surgery to shrink the cancer), your surgeon may recommend a procedure called targeted axillary dissection.

Targeted axillary dissection combines a sentinel node biopsy with the removal of the single lymph node that is known to contain cancer. This helps prevent false-negative lymph node results after neoadjuvant chemotherapy. This technique can also reduce the risk of lymphedema because fewer nodes are removed.

To prepare for a targeted axillary dissection, doctors use a needle or other device to place a marker in the cancerous lymph node before chemotherapy begins. The marker may be a magnetic or radioactive seed, a radar reflector, or another type of marker that can be located using a wireless probe.

After chemotherapy is finished, the surgeon uses the wireless probe to find the marker and remove it along with the lymph node. A sentinel node biopsy is performed at the same time.

Targeted axillary dissection after neoadjuvant chemotherapy reduces the risk of false-negative lymph node status results from more than 10% down to about 2%.

Some people can avoid lymph node removal

Newer studies have shown that certain people and breast cancers do not require lymph node removal.

In most cases, people diagnosed with ductal carcinoma in situ (DCIS, or noninvasive breast cancer) undergoing lumpectomy do not need to have lymph nodes removed.

Now, due to new research, there are some people with invasive breast cancer who do not need to have lymph nodes removed. This includes people age 70 or older with small (less than 2 centimeters) hormone receptor-positive, HER2-negative tumors who do not have axillary (armpit) swelling. Studies found that for these people, sentinel lymph node biopsy did not change cancer outcomes. This is now part of the Society of Surgical Oncology’s Choosing Wisely Guidelines (PDF).

Other recent studies have shown that sentinel lymph node biopsy can be safely omitted in postmenopausal women age 50 and older with small (less than 2 centimeters) hormone receptor-positive, HER2-negative tumors and an ultrasound that does not show any abnormal-appearing axillary lymph nodes. Radiation therapy is usually recommended after the cancer-removing surgery. Your radiation oncologist will recommend a specific schedule of radiation therapy for you.

Questions to ask your doctor

If you are having lymph node surgery, here are some key questions to consider before surgery.

• Will I have a sentinel lymph node biopsy or an axillary dissection?
• Why do you recommend one surgery over the other?
• What side effects might happen soon after surgery, and what could develop later on?
• What steps can I take before and after surgery to lower my risk of lymphedema?
• Should I have neoadjuvant therapy, treatment before surgery?

Side effects of lymph node surgery

Lymph node surgery is an important part of diagnosing, staging, and treating breast cancer.

But like any surgery, lymph node surgery can cause side effects. These may appear sooner after surgery or develop later.

The type and severity of side effects often depend on the number of lymph nodes removed. Sentinel lymph node biopsy usually has fewer and milder side effects than axillary lymph node dissection.

Side effects that can happen in the first days or weeks after surgery include:

• Numbness in the underarm or upper arm
• Weakness in the arm or shoulder
• Seroma, a buildup of clear fluid under the skin that may need to be drained
• Pain, tenderness, or stiffness at the surgery site

Lymph node surgery can also have serious, long-term side effects, such as:

• Loss of sensation under the arm and in the back of the arm (more common with axillary dissection)
• Shoulder and armpit stiffness (more common with axillary dissection; usually milder with sentinel lymph node biopsy)
• Axillary web syndrome (cording), which can happen if tight, rope-like cords form under the skin of the arm; this can sometimes limit arm movement, but working with a physical therapist can help
• Lymphedema, a swelling condition that can become chronic without treatment

Talk with your doctors about these risks as you are planning your surgery:

• Ask about a lymphedema screening and monitoring plan that starts before surgery with a baseline arm measurement.
• Ask about stretching exercises you can do after surgery to reduce stiffness and lower your risk of lymphedema.

Learn more on the Lymphedema page.

Results after surgery

After lymph node surgery, the removed nodes are sent to a lab for testing. A doctor called a pathologist examines them and creates a pathology report.

Your doctor will review the report with you and explain what it means for your care.

If cancer cells are found in the lymph nodes, you and your care team may discuss additional treatment options, such as:

• Additional lymph node surgery with an axillary lymph node dissection if cancer was found during sentinel node biopsy
• Radiation therapy to the breast or underarm
• Chemotherapy to target cancer cells that may have spread beyond the lymph nodes
• Hormonal therapy, targeted therapy, or immunotherapy, depending on the tumor’s features

Your lymph node results do not affect the kind of breast surgery (mastectomy or lumpectomy) you need, and your treatment plan will not be based on lymph node results alone. Doctors also look at other features of the cancer, including biomarkers, such as hormone and HER2 receptors. Biomarker tests help guide which treatments are most likely to work for you. Learn more on the Biomarker testing page.

Post-surgery follow-up care

Follow-up care is an important part of recovery and ongoing treatment after you have lymph node surgery. Your care team will schedule regular appointments to monitor your health and perform breast and lymph node exams.

Talk with your team about a plan to manage potential side effects, such as lymphedema or stiffness.

You may also need imaging tests to watch for changes in the breast or chest area. These can include:

• Mammogram
• Ultrasound
• MRI, in some cases

If you are receiving more treatment after surgery, such as chemotherapy, radiation, or hormonal therapy, you will also have regular visits with your doctor during and after those treatments.

Staying on top of follow-up visits helps your care team find and address any issues early. Visit When to have follow-up visits to learn more.