Tests to check your lymph nodes
Your specialist will examine the nodes closest to the melanoma 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 abdomen, the lymph nodes in your groin, armpits, above the collar bones and in the neck will be checked. If any of these lymph nodes are obviously swollen, your specialist may suggest that you have a fine needle aspiration. Having swollen lymph nodes doesn’t necessarily mean that the melanoma has spread. An infection, for example, can cause lymph nodes to swell.
Even if your lymph nodes aren’t swollen, your specialist may ask you to think about having some of the other tests mentioned here. It’s not yet clear how useful it is to check the lymph nodes. Even if the tests are positive, there’s no evidence that removing all the lymph nodes delays or reduces the chance of the melanoma coming back. Because of this, your specialist may leave the decision about whether you have these tests up to you. However, checking the lymph nodes can give you and your doctors more accurate information about the stage of the melanoma. And you may feel better knowing that the affected lymph nodes have been removed.
If you have a swollen lymph node, your specialist may use a fine needle and syringe to remove some fluid from the node. The fluid is then examined under a microscope to see if it contains any cancer cells. If cancer cells are present, you’ll have surgery to remove all the lymph nodes in that area.
Lymph node sampling involves having a few lymph nodes from the area closest to the melanoma removed. This is done under a general anaesthetic. The lymph nodes are examined to see if they contain any cancer cells. If any of them contain cancer cells, the rest of the lymph nodes in that area will be removed in a further operation.
Sentinel lymph node biopsy (SLNB)
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A test called a sentinel lymph node biopsy (SLNB) is sometimes done to find out if the nearby lymph nodes are affected. It may also be carried out if the lymph nodes appear normal - this is if there’s a risk that the melanoma may have spread to them. SLNB is still being researched as a test to check the lymph nodes of people with melanoma. SLNB is usually done at the same time as a wide local excision.
If the result is negative, it’s unlikely that other lymph nodes are affected so you won’t need to have surgery to remove them. If the test is positive, all the lymph nodes in the area will be removed.
An SLNB involves having a tiny amount of a mildly radioactive liquid injected around the area of the melanoma after it‘s been removed. The lymph nodes close to the melanoma are then scanned to see which ones have absorbed the radioactive liquid first. A blue dye is also injected into the area during the operation. The dye stains the lymph nodes blue. The surgeon removes the lymph node(s) that become blue or radioactive first - these are called the sentinel node(s).
The sentinel node(s) can then be tested to see whether they contain melanoma cells. The risk of problems following SLNB is low and they tend to be mild. There’s a very small chance of lymphoedema (swelling in the area) following a sentinel node biopsy.
Some hospitals use ultrasound to check the lymph nodes. 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 your melanoma has spread to the lymph nodes, you may have some of the following tests. These tests will show whether the melanoma has spread to other parts of the body.
CT scan (computerised tomography) scan
A CT scan takes a series of x-rays, which build up a three-dimensional picture of the inside of the body.
The scan takes 10–30 minutes and is painless. It uses a small amount of radiation, which is very unlikely to harm you and will not harm anyone you come into contact with. You’ll be asked not to eat or drink for at least four hours before the scan.
You may be given a drink or injection of a dye, which allows particular areas to be seen more clearly. This may make you feel hot all over for a few minutes. It’s important to let your doctor know if you are allergic to iodine or have asthma, because you could have a more serious reaction to the injection.
You’ll probably be able to go home as soon as the scan is over.
MRI (magnetic resonance imaging) scan
This test uses magnetism to build up a detailed picture of areas of your body. The scanner is a powerful magnet, so you may be asked to complete and sign a checklist to make sure it’s safe for you. The checklist asks about any metal implants you may have, for example a pacemaker, surgical clips or bone pins. You should also tell your doctor if you’ve ever worked with metal or in the metal industry, as very tiny fragments of metal can sometimes lodge in the body. If you do have any metal in your body, it’s likely that you won’t be able to have an MRI scan. In this situation, another type of scan can be used.
Before the scan, you’ll be asked to remove any metal belongings including jewellery. Some people are given an injection of dye into a vein in the arm, which doesn’t usually cause discomfort. This is called a contrast medium and can help the images from the scan to show up more clearly. During the test you’ll lie very still on a couch inside a long tube (cylinder) for about 30 minutes. It’s painless but can be slightly uncomfortable, and some people feel a bit claustrophobic.
It’s also noisy, but you’ll be given earplugs or headphones. You’ll be able to hear and speak to the person operating the scanner.
PET (positron emission tomography) scan
A PET scan uses low-dose radioactive sugar to measure the activity of cells in the body. A very small amount of a mildly radioactive sugar is injected into a vein in your hand or arm before you have the scan. Areas of cancer are normally more active than surrounding tissue and absorb more of the sugar, which shows up on the scan.
Waiting for test results
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It may take several days for the results of your tests to be ready, and a follow-up appointment will be made for you. This waiting period can often be a very anxious time and it may help you to talk things over with a relative, close friend or a specialist nurse at the hospital.
If your melanoma is found to have spread to the lymph nodes closest to your melanoma, further surgery will be planned to remove these.
If the melanoma has spread to other parts of your body, you may have drug treatments such as chemotherapy or biological therapies, or a combination of these. Occasionally surgery or radiotherapy may also be used.