Tests to check your lymph nodes

The most common place for melanoma cells to spread is to the lymph nodes closest to the melanoma. Your specialist will examine these nodes to see if they look or feel swollen.

You may also have some tests to check whether any lymph nodes are affected by melanoma. These tests include:

  • A sentinel lymph node biopsy (SLNB) – this removes your sentinel lymph nodes. If there is no melanoma found in the sentinel lymph nodes, then it is unlikely that it has spread.
  • An ultrasound – this uses sound waves to make up a picture of part of your body.
  • A fine needle aspiration (FNA) – this withdraws some sample cells from your lymph nodes with a fine needle.

If melanoma cells are found in your lymph nodes, you may have other tests to see if it has spread elsewhere in the body. These might include CT, MRI or PET scans.

Waiting for your test results can be difficult. It can help to talk about your worries with someone close to you.

Lymph node testing

The most common place for melanoma cells to spread to is to the lymph nodes closest to the melanoma. Your specialist will examine these nodes to see if they look or feel swollen. For example, if the melanoma is on your leg they’ll examine the lymph nodes behind your knee and in your groin. If it’s on your chest, back or tummy (abdomen), they’ll check the lymph nodes in your groin and armpits, above the collar bones, and in the neck.

The lymphatic system
The lymphatic system

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Some people will have tests to check whether their lymph nodes are affected. Not everyone needs these tests – it depends on the stage of the melanoma and if the lymph nodes look or feel swollen.

If your tests show that the melanoma has spread to the lymph nodes, you’ll be advised to have surgery to remove all the lymph nodes in that area.


Sentinel lymph node biopsy (SLNB)

You may be offered a test called a sentinel lymph node biopsy (SLNB). This may be done even if the lymph nodes aren’t swollen. It’s done at the same time as your wide local excision.

The sentinel nodes are the first ones that lymph fluid drains to from your melanoma. If the melanoma has spread to nearby nodes the sentinel nodes are the ones that are most likely to be affected.

A SLNB can tell your doctors more about the stage of your melanoma. Your specialist will talk to you about whether a SLNB is suitable for you. There are still some questions about the helpfulness of SLNB’s, so they may leave the decision about whether you have one up to you.

Having a sentinel lymph node biopsy

Before your wide local excision, a doctor will inject a tiny amount of a mildly radioactive liquid around the area of your melanoma (where you had your excision biopsy). You will then have a scan to see which lymph nodes the liquid travels to first. These are the sentinel nodes.

Then, during the wide local excision, the surgeon injects a blue dye into the same area as the radioactive liquid. The dye stains the sentinel lymph nodes blue. This helps the surgeon find them and remove them. They are sent to a laboratory and examined under a microscope to see if they contain melanoma cells.

If the sentinel nodes don’t contain cancer cells, it’s unlikely that other lymph nodes are affected so you won’t need to have surgery to remove them.

If they do contain cancer cells, you will be offered further surgery to remove all the lymph nodes near to your melanoma. Your hospital team will discuss with you the benefits and disadvantages of having all the lymph nodes removed.


Ultrasound and fine needle aspiration (FNA)

If any of your lymph nodes are swollen, your specialist may suggest that you have an ultrasound and fine needle aspiration to check them. Having swollen lymph nodes doesn’t necessarily mean that the melanoma has spread. An infection, for example, can cause lymph nodes to swell.

Ultrasound

Ultrasound uses sound waves to make up a picture of a particular area of the body. It’s a painless test and only takes a few minutes. Once you’re in a comfortable position, you’ll have a gel spread over the area around the lymph nodes that are being examined. A small device like a microphone, which produces sound waves, is then passed over this area. The echoes are converted into a picture by a computer. If the ultrasound of the lymph nodes is abnormal the doctor will do a fine needle aspiration on the node or nodes.

Fine needle aspiration

A fine needle aspiration is a quick simple test. The doctor puts a fine needle into the lymph node and withdraws a sample of cells into the syringe. The cells are examined under a microscope to see if they contain any cancer cells.

If they do, you may have other tests to see if the melanoma has spread anywhere else in the body. If the melanoma has only spread to nearby lymph nodes you’ll be offered surgery to remove all the lymph nodes in that area. Your doctors will discuss this with you and tell you about the benefits and disadvantages of having the nearby lymph nodes removed.


Other tests

If your melanoma has spread to the lymph nodes, you may have other tests to see if it has spread elsewhere in the body.


CT scan

A CT (computerised tomography) scan uses x-rays to build a three-dimensional picture of the inside of the body. You may be given either a drink or injection of dye. This is to make certain areas of the body show up more clearly. This scan takes around 30 minutes and is painless. We have more detailed information about having a CT scan.


MRI scan

This scan uses magnetism to build up a detailed picture of areas of your body. You may be given an injection of dye, into a vein, to improve the images from the scan. This test is painless and will take around 30 minutes. We have more detailed information about having an MRI scan.


PET scan

A PET scan measures the activity of cells in different parts of the body. It can be used to find out if a tumour is cancerous or non-cancerous, if it is growing and if it has spread to other parts of the body. We have more detailed information about having a PET scan.


Waiting for test results

Waiting for test results can be a difficult time. It may take from a few days to a couple of weeks for the results of your tests to be ready. You may find it helpful to talk with your partner, family or a close friend. Your specialist nurse or one of the organisations listed on our database, can also provide support. You can also talk things over with one of our cancer support specialists on 0808 808 00 00.


Back to Tests and scans

Being diagnosed with melanoma

Usually you’ll begin by seeing your GP, who will examine you and decide whether to refer you to a hospital specialist for further tests and treatment.