How advanced melanoma is diagnosed

If you’ve been treated for a melanoma before, you may be attending a clinic for check-ups. Your specialist or GP will arrange tests to investigate any new symptoms you have. The tests your doctor arranges will depend on your particular symptoms.

The most common place for melanoma cells to spread to is the lymph nodes, so your doctor will test them first. If those tests are positive, or if you have other symptoms of advanced melanoma, you may have one or more of the following tests:

  • Blood tests
  • Chest x-ray
  • CT (computerised tomography) scan – this uses x-rays to build up a three-dimensional picture of your body
  • MRI (magnetic resonance imaging) scan – this uses magnetism to build up a picture of your body
  • Ultrasound scan – this uses sound waves to build up a picture of part of your body
  • Bone scan
  • PET (positron emission tomography) scan – this uses low-dose radioactive sugar to measure the activity of cancer cells.

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

How advanced melanoma is diagnosed

If you have been treated for a melanoma before, you may still be attending a clinic for check-ups and possibly scans. Sometimes a recurrence of the melanoma will be found at one of these appointments, before you develop any symptoms.

If you notice new symptoms between appointments, you should contact your specialist or GP (family doctor). They will arrange tests to investigate your new symptoms. The tests your doctor arranges will depend on the symptoms you have.

Tests to check your lymph nodes

If you have just been diagnosed with a primary melanoma, you may have tests to check whether the cancer cells have spread to the lymph nodes nearby.

If these tests show that there is cancer in the lymph nodes, or if you have symptoms that suggest the melanoma has spread elsewhere, you may have some of the following tests.

Blood tests

Samples of your blood may be taken to check your general health, the number of blood cells in your blood (blood count) and to see how well your kidneys are working. We have more detailed information about blood tests.  

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 to 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.

CT scan
CT scan

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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 is 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 will probably be able to go home as soon as the scan is over.

Chest x-ray

This uses x-rays to take a picture of your chest, to check your lungs and heart.

MRI scan

An MRI scan 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 is safe for you. The checklist asks about any metal implants you may have, such as a pacemaker, surgical clips or bone pins, etc.

You should also tell your doctor if you have 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 is likely that you will not be able to have an MRI scan. In this situation, another type of scan can be used. Before the scan, you will be asked to remove any metal belongings including jewellery.

Some people are given an injection of dye into a vein in the arm, which does not 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 will lie very still on a couch inside a long cylinder (tube) for about 30 minutes. It is painless but can be slightly uncomfortable, and some people feel a bit claustrophobic. It is also noisy, but you will be given earplugs or headphones. You can hear, and speak to, the person operating the scanner.

Ultrasound scan

Ultrasound scans use sound waves to build up a picture of part of the inside of the body, such as the abdomen, liver or pelvis.

If you have a pelvic ultrasound, you will be asked to drink plenty of fluids so that your bladder is full. This helps to give a clearer picture. An ultrasound specialist will then spread a gel on to your abdomen and gently rub a small, microphone-like device, which produces sound waves, over the area. The sound waves are converted into a picture by a computer. An ultrasound scan is painless and only takes a few minutes.

Bone scan

A bone scan can show up any abnormal areas of bone. A very small amount of a mildly radioactive substance is injected into a vein, usually in your arm. This travels around the body and bloodstream. Abnormal areas of bone absorb more radioactivity than normal bone and show up on a scanner.

You will have to wait for up to three hours after having the injection before you have a scan. This is to allow time for the bone to absorb the radioactive substance. It is a good idea to take a book or a magazine with you to help pass the time. After a few hours, you will have a scan of your whole body.

Bone scans cannot always tell whether an abnormal area is due to cancer or other conditions, such as arthritis. Sometimes more detailed scans will be needed, such as CT or MRI scans.

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

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.

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