Tests to check your lymph nodes
Your specialist will examine the nodes closest to the melanoma to see if they look or feel swollen.
Sentinel lymph node biopsy
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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. You can find out more about wide local excision surgery in our section on treatment with surgery.
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 SLNBs, 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’ll have 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)
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If any of your lymph nodes are swollen, your specialist may suggest that you have an ultrasound and a 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 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.
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 (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 will 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.
Hear from a superintendent radiographer in CT, and Jyoti, a CT scan patient, about what to expect when having a CT scan.
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, bone pins, etc. 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 cylinder (tube) 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 can 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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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 can also provide support.