Lymph nodes explained: Location, function, swelling and cancer connection

When people get sick with a cold or sore throat, they often say, ‘My glands are swollen.’ What they’re really referring to are the lymph nodes in their neck.

Lymph nodes are small, bean-shaped structures that are part of your lymphatic system. They work within your immune system as a filter to help fight off infection, disease and potentially harmful foreign substances. 

Here, I’ll share more about lymph nodes, including where they’re located in your body, how they function within your immune system and the role they play in cancer detection and prevention.

What are lymph nodes, and what do they do?

Lymph nodes are part of your immune system. They’re connected to one another by an intricate system of lymphatic vessels, which carry lymph fluid throughout your lymphatic system.

Lymph nodes contain white blood cells that help fight infections, destroy abnormal cells that could become cancerous and destroy cancer cells before they spread to other parts of the body.

Where are lymph nodes located?

You have several hundred lymph nodes located throughout your body. Certain areas of the body have clusters of lymph nodes, including:

• your axilla (armpit)
• along your neck
• your chest, on either side of the lungs
• your groin

What causes swollen lymph nodes?

Infection is the most common cause of swollen lymph nodes. For example, your lymph nodes may swell if you have a viral infection like the cold or the flu, or a bacterial infection like strep throat. This means that the white blood cells in your lymph nodes are working to filter out the viruses, harmful bacteria and damaged cells.

Trauma or injury that damages a particular region of your body can also cause the lymph nodes surrounding that area to swell.

Sometimes, swollen lymph nodes can be a sign of a more serious condition, such as lymphoma or other types of cancer. 

Lymphedema is swelling in the arm or leg that occurs when the lymphatic system doesn’t drain properly, causing fluid to build up. That buildup of fluid causes swelling, heaviness and tightness.

Cancer treatment, like surgery, chemotherapy and radiation therapy, is the top cause of lymphedema in the U.S. Lymphedema can be treated with:

• Massage
• Bandaging
• Pumping
• Compression garments
• Physical therapy
• Exercise
• Surgery

When should you worry about your lymph nodes?

If your lymph nodes are swollen due to an infection, the swelling will likely go away as your body rids itself of the infection and you start feeling better.

See your doctor if you have swollen lymph nodes for an unexplained reason, if they continue to get bigger or if they don’t get better after two weeks.

Can lymph nodes be cancerous?

Sometimes swollen lymph nodes can be the first sign of cancer. This is often the case with lymphoma, a type of blood cancer that develops in the lymph nodes. Other times, lymph nodes can swell if cancer from another part of the body has spread to nearby lymph nodes. For example, breast cancer often spreads to lymph nodes in the axilla (armpit).

If you’re ever concerned about swelling in your lymph nodes, see a doctor to get it checked out.

It’s important to note that most causes of swollen lymph nodes are not due to cancer.

How are lymph node conditions diagnosed?

An ultrasound is the most common diagnostic test to evaluate lymph nodes. Your doctor may also use other imaging techniques, like a CT scan or PET scan, to identify abnormal lymph nodes. If your doctor suspects cancer, they’ll typically recommend a biopsy.

What happens if your lymph nodes are removed?

The more lymph nodes you have removed, the more your risk for lymphedema increases. But other factors, like obesity, increase your lymphedema risk as well. So, it doesn’t mean that you will get lymphedema if you have lymph nodes removed.

There’s no magic number. Remember, your body has hundreds of lymph nodes. They help your body monitor for abnormal cells and ward off infection.

Lymph nodes may be removed for several reasons, such as surgery for cancer treatment, a biopsy or inadvertently during certain operations like plastic surgery unrelated to cancer treatment.

We try to identify early signs of lymphedema so that we can start treatment and prevent the condition from getting worse. If you’re an MD Anderson patient dealing with lymphedema, we’ll usually refer you to Rehabilitation Services; they may recommend exercise or manual lymph drainage. Some patients will need surgery.

The key is to catch lymphedema early, so we can manage and ease your symptoms.  

Edward Chang, M.D., is a plastic and reconstructive surgeon who treats cancer patients who develop problems with their lymphatic system after treatment.

Request an appointment at MD Anderson online or call 1-877-632-6789.