When Do Swollen Lymph Nodes Mean Cancer?

Medically Reviewed by Poonam Sachdev on June 04, 2024
8 min read

Swollen lymph nodes, or what doctors call lymphadenopathy, are often caused by infections or a condition that affects your immune system. They usually clear up as your body heals.

But sometimes, cancer cells may travel through your bloodstream and end up in your lymph nodes, or even start there.

Your doctor can help you figure out what's causing your lymph nodes to feel sore and larger than usual.

Your lymphatic system is a key part of your immune system. It's made up of organs, blood vessels, and tissues that help you stay healthy. It includes your:

  • Bone marrow, the innermost part of your bones, where new blood cells are made
  • Thymus, a gland behind your breastbone where special immune cells called T-cells are made
  • Lymph nodes (glands)

More than 600 small, kidney bean-shaped lymph nodes are clustered throughout your body -- under your neck, in your armpits and groin, and in the middle of your chest and belly. They store immune cells and act as filters to remove germs, dead and damaged cells, and other waste from your body.

Swollen lymph nodes are a sign that they're working hard. More immune cells may be going there, and more waste could be building up. Swelling usually signals an infection of some kind, but it could also be from severe allergies, ongoing stress, conditions such as rheumatoid arthritis or lupus, or rarely, cancer.

Often, swollen lymph nodes will be close to where the issue is. For instance, when you have strep throat, lymph nodes in your neck may swell. Shingles will cause swollen lymph nodes in the area where the rash breaks out. People who have breast cancer may get swollen lymph nodes in their armpit.

When two or more areas of your lymph nodes are swollen, an issue is affecting your entire body. The medical term for this is generalized lymphadenopathy.

It can happen for a range of reasons, from chickenpox and HIV to a type of cancer.

Your glands are more likely to swell if:

  • You're older.
  • You have a weakened immune system.
  • You have unprotected sex or inject drugs.

If cancer is the cause of your swollen glands, it's usually because cancer cells have spread there from another place in your body. This is called metastasis. Once a tumor forms in your body, cancer cells can break loose from it and travel to different organs through your bloodstream or your lymph system.

Usually, you should be able to gently move swollen glands under your skin. They'll feel soft and could be tender or slightly painful to the touch.

Cancerous lymph nodes

There's no way to tell if a swollen gland is a sign of cancer just by how it feels.


You'll often have a good idea why a lymph node is swollen -- for instance, you've got a cold, or your tooth is infected, or you have a cut that isn't healing well. But If you can't come up with a reason, it may be time to get checked out.

You'll also want to make an appointment if your glands:

  • Are around 1/2 inch or bigger
  • Have been swollen for over 2 weeks
  • Don't move under your skin
  • Feel hard to the touch
  • Are draining pus or another type of discharge
  • Are covered with red, dry skin

Your doctor should also know if you have any of these symptoms:

Swollen lymph nodes close to your collarbone or the lower part of your neck are more likely to be cancer. On the right side, they're linked to your lungs and esophagus , while on the left, they relate to organs in your belly. Swollen lymph nodes in your armpit when you don't have a rash or close to your elbow can also raise concern.

But keep in mind that many other health issues besides cancer can cause your glands to look or feel different. There's no way of knowing the cause until you see a doctor and tests are done.

Because cancer is rarely the cause of swollen glands, your doctor will probably try to rule out more common reasons first. They'll do a physical exam and ask you about recent events, such as if you've:

  • Been scratched by a cat
  • Been bitten by a tick
  • Eaten undercooked meat
  • Had unprotected sex with a new partner
  • Injected drugs
  • Traveled to certain areas
  • Recently had a COVID-19 vaccine

They'll want to know what medications you're taking and other symptoms you have.

Tests your doctor may order

Your doctor will probably do a complete blood count (CBC) to get a picture of your general health as well as more detailed information about your white blood cells, which fight infection. Depending on your other symptoms and your medical history, they may want additional blood tests or X-rays, too.

For instance, if you have swollen lymph nodes throughout your body, your doctor may ask for a CBC, a chest X-ray, and an HIV test. If those results are normal, you might get other tests, perhaps for tuberculosis or syphilis, an antinuclear antibody test (which checks your immune system), or a heterophile test (which looks for the Epstein-Barr virus). 

If these tests don't show another cause and your glands don't go back to normal in 3-4 weeks, your doctor will likely do a biopsy. Using a very thin needle, they'll take a sample of cells from one of your glands and send it to a lab for a better look. Since the swelling may go away or another cause could be found while you're waiting to do a biopsy, this time lag prevents you from getting procedures you don't need.

Tests that check for cancer

If your doctor thinks your swollen lymph nodes could be cancer, tests and imaging can confirm the diagnosis or point to something else. Based on where the cancer might be, you could get a chest X-ray, an ultrasound, a CT scan, or an MRI. A scan called FDG-PET, which stands for fluorodeoxyglucose with positron emission tomography, can help find lymphoma and other cancers.

You'll probably get a procedure called a lymph node dissection or lymphadenectomy. Cells from one or more of your nodes are removed. It's a minor surgery that lasts about an hour. You'll be given anesthesia that allows you to sleep through it.

The sample cells from your lymph node then get sent to a lab so a specialist can check them with a microscope for cancer.

Cancer in your lymph nodes is often a cancer that has spread from another place in your body. Rarely, the cancer begins in your lymph nodes. Lymphoma is a broad term that includes any cancer of your lymph system.

Some types include:

  • Hodgkin's lymphoma (HL). There are many subtypes, but classic Hodgkin lymphoma accounts for 95% of all cases in the U.S. It's also the most treatable.
  • Non-Hodgkin's lymphoma (NHL). This cancer begins in your white blood cells. There are different types, depending on which specific kind of white blood cell is affected.
  • Acute lymphocytic leukemia (ALL). Leukemia refers to cancers that start in new blood cells. In this case, ALL affects early forms of lymphocytes, which are a type of white blood cell.

If cancer is found in one of your lymph nodes, more tests and procedures are usually done. The more information your doctor has about your cancer, including the size of the tumor, where it is in your body, and how much it's spread, the more accurate they can be when talking about your outlook and treatment options.

How cancer is staged

Doctors often use a type of system to help stage, or describe, your cancer and decide the next steps to take. One that's often used is called the tumor-nodes-metastasis (TNM) staging system.

Generally speaking, it provides details about the:

  • Tumor (T): Including its location and size.
  • Nodes (N): If the cancer's spread to nearby lymph nodes, and if so, how many.
  • Metastasis (M): If cancer cells have traveled to other parts of your body.

Based on that data, your doctor can then assign a stage to your cancer.

Stage I. Smaller tumors that haven't spread to nearby lymph nodes or other areas.

Stage II. Larger tumors that haven't spread anywhere else.

Stage III. Large tumors that have spread to lymph nodes.

Stage IV. Cancer that has spread from the original tumor to other body parts.

Staging may not be used if you have leukemia.

Based on the source of the cancer cells and how far away it is from your swollen glands, your doctor will suggest a treatment plan. It could include surgery, radiation, chemotherapy, or a combination of treatments.

Once cancer cells have entered your lymph nodes, they're more likely to come back after treatment. Removing all the lymph nodes that were affected can help stop this from happening.

Your doctor will decide the best time to remove any lymph nodes that contain cancer cells. You could have this procedure after another cancer therapy, such as radiation or chemotherapy. Or your doctor may do it right away. It may be a standalone lymphadenectomy, similar to what you had before when you were first diagnosed. Or it could be part of a larger surgery to remove a tumor.

Most of the time, it's a minor outpatient procedure, meaning that you can go home the same day and don't have to stay overnight in a hospital. Any pain you feel should be mild and able to be managed with over-the-counter medications. But some complications are possible. They include:

Nerve damage. If the nerves around the gland were removed during the surgery, that area may feel numb or stiff.

Fibrosis. Thick scar tissue could build up over the site, making it harder for you to move that body part.

Lymphedema.Lymph is the fluid that travels through your lymphatic system. If it stops flowing properly and gets backed up somewhere in your body, it's a condition called lymphedema. This can happen after you've had lymph nodes removed.

If you notice swelling in the area, talk to your doctor. If the buildup is small and you caught it early, home care may help. For instance, your doctor may give you special exercises to do, since moving around can help flush the excess fluid. Or they could give you a compression garment to wear to keep more lymph from pooling in the area.

Swollen glands are a sign that your immune system is fighting off an infection or illness. They're usually not a sign of cancer. But if they don't clear up quickly or you have other symptoms, see your doctor so they can run tests and find the cause.

How do you relieve swollen lymph nodes?

If your glands are sore, you can try:

  • Warm compresses (such as a heating pad)
  • Over-the-counter pain relievers. Ask your doctor if ibuprofen or acetaminophen is safe for you to take.
  • Rest. This will help your immune system fight off whatever's making you feel unwell.

While none of these tips will bring your glands back down to normal size, they will help make you more comfortable until they shrink on their own.

How long does a swollen lymph node take to go away?

Once your infection or illness clears up, the swelling in your glands should, too.