Tests for melanoma skin cancer
There are a number of tests to check for melanoma skin cancer. Your GP may do some of these. A specialist doctor might arrange some other tests.
Tests your GP might do
Many people start by seeing their GP if they have symptoms that may be due to melanoma skin cancer. Your GP can do some tests to help them decide whether you need to be referred to a specialist. They might:
- do a physical examination of your skin
- look closely at your mole or skin with a special instrument (dermatoscope)
- take or arrange photographs of the mole or abnormal patch of skin
Physical examination
Your GP will look at the mole or abnormal area of skin. They may measure it with a ruler or a special marker scale. They can compare the size, shape and colour to other moles you have or other areas of your skin.
Your GP may also feel around your neck, armpits or groin. This is to see if your 
are swollen.
Looking at your mole or skin (dermoscopy)
Your GP might look at your mole or skin through a special instrument called a dermatoscope. It makes things look bigger, like a magnifying glass.
Below are examples of dermatoscopes.
Your GP puts some gel or oil on the mole or abnormal area of skin. They put the dermatoscope on top and look through it. This lets them examine the area very closely. The oil or gel helps the dermatoscope work better. It does not hurt or damage the skin.
Some GPs are trained to use a dermatoscope. If your GP isn't, a skin specialist will look using a dermatoscope, if you need to see them.
Photographs for teledermatology
Sometimes your GP might want a specialist skin doctor (dermatologist) to look at the mole or abnormal area of skin. This is to help them decide if you need to be referred to the hospital. Your GP will take some photos of the mole or abnormal area of skin to send to the dermatologist. This is called teledermatology. If your GP can’t take the photographs you might have them taken at a special clinic.
Your GP may ask you to take photographs of the mole or skin patch. They will tell you the best way to take them. They will also tell you how to safely send the photographs.
Tests your specialist doctor might do
Depending on the features of the abnormal mole or area of skin your GP may refer you to a specialist doctor. You usually see a dermatologist. Sometimes you might see a .
The specialist doctor usually arranges more tests. These may include:
- dermoscopy if not done by your GP
- taking photographs to see if the mole or abnormal patch of skin changes (baseline photographs)
- removing the mole or abnormal patch of skin (excision biopsy) to find out if you have melanoma
Photographs to see if the mole or abnormal patch of skin changes (baseline photographs)
Your doctor uses photographs to keep a record of what the mole or area of skin looked like when you first saw them. These are called baseline photographs.
Sometimes they will ask you to come back in a few months to see if the mole or patch of skin has changed. They do this by comparing it to the baseline photographs. They will then decide if it needs to be removed or not.
Removing a mole or patch of skin (excision biopsy)
Your doctor might remove the abnormal area to find out if it's a melanoma skin cancer. This is called an excision biopsy. You have this under a so you will be awake during the procedure.
You lay on a couch and your doctor puts an injection of local anaesthetic into the skin around the mole or abnormal area. This makes the area numb. They remove the abnormal area and a small amount of skin (around 2mm) around it. This is called the margin.
They send the abnormal area or mole to the laboratory. A specialist doctor (pathologist) looks at the tissue under a microscope. This is the only way to know for certain if you have melanoma.
Your doctor might use stitches to close the wound. These might dissolve on their own or a nurse may need to remove them. You may have a small dressing over the top. Your doctor or nurse will tell you:
- if the stitches need to be removed
- where and when to get the stitches removed
- how to look after the wound and dressing
You usually go home the same day. Your doctor will tell you when to expect the results. It can take a couple of weeks.
If the excision biopsy shows you have melanoma skin cancer
Your doctor will normally recommend an operation to remove a larger area of skin around where the melanoma was. This is called a wide local excision.
They might also recommend you have tests:
- to check your lymph nodes
- on the melanoma to look for
gene changes (mutations)
If you have a wide local excision for an early stage melanoma you may not need any more tests afterwards. Your doctor will talk to you about this.
Tests to check your lymph nodes
Lymph nodes are glands. They are found in many parts of the body including the armpits, neck and groin. They help drain away waste fluid and damaged cells. They also contain cells that fight infection.
There is a risk that melanoma cells can spread to the lymph nodes. The risk is higher in thicker melanomas. But it’s rare in melanomas that are less than 1mm thick.
Your doctor may check your lymph nodes for melanoma by taking a biopsy. Which lymph nodes they take the biopsy from depends where on your body the melanoma skin cancer was.
There are different types of lymph node biopsy. Which one you have depends on:
- the size of the melanoma
- if your doctor can feel your lymph nodes (palpable lymph nodes)
- how easy it is to take a biopsy of the lymph node
Sentinel lymph node biopsy (SLNB)
The first place that melanoma skin cancer usually spreads to is the nearby lymph nodes. The sentinel lymph nodes are the first lymph nodes the cancer can reach.
During an SLNB your doctor removes the sentinel nodes and sends them to the laboratory. This is to check them for small amounts of melanoma that can only be seen under a microscope (microscopic disease).
You have an SLNB under a at the same time as the wide local excision.
Fine needle aspiration or core needle biopsy
Sometimes your doctor might recommend a different type of lymph node biopsy. This is either a fine needle aspiration (FNA) or core needle biopsy. You usually have one of these if your doctor can feel your lymph nodes are swollen, or they look swollen on an ultrasound scan.
Your doctor can use an ultrasound scanner to help them take the biopsy. They send the sample of fluid or tissue to the laboratory to be checked for cancer cells.
Fine needle aspiration (FNA)
Your doctor uses a thin needle to go through your skin and into the swollen lymph node. They use a syringe at the end of the needle to take out some fluid and small pieces of tissue.
Core needle biopsy
This is similar to an FNA but your doctor uses a thicker needle. This means they can remove a larger amount of tissue.
Your doctor injects some local anaesthetic around the swollen lymph node before you have a core needle biopsy. This makes the area numb.
Genetic tests on the melanoma
For stage 3 and 4, and some stage 2 melanoma skin cancers, your doctor tests the melanoma cells for gene changes (mutations). This includes the BRAF V600 gene. They usually do the genetic tests on the melanoma that was removed. But sometimes they need to take another sample. For example, from where the cancer has spread.
Changes in the BRAF V600 gene cause the melanoma to make lots of BRAF protein. This protein tells the melanoma cells to grow and divide. Having lots of the protein means the cells grow and divide more quickly.
If you have a change in the BRAF V600 gene, doctors describe the melanoma as BRAF positive or BRAF mutant. If you don’t have the change, then the melanoma is called BRAF negative or BRAF wild type.
Knowing if you have a gene change helps your doctor recommend the most suitable treatment for you.
Scans for melanoma skin cancer
Doctors use CT or MRI scans to check if the melanoma has spread. Not everyone will need these.
CT scan
CT (or CAT) scan stands for computed (axial) tomography. It is a test that uses x-rays and a computer to create detailed pictures of inside your body.
You may have to drink a jug of water or contrast medium before the test. This is a dye that shows up body tissues more clearly on the scan. You might also have an injection of contrast medium.
MRI scan
MRI stands for magnetic resonance imaging. It uses magnetism and radio waves to take pictures of inside your body.
When you have a CT or MRI scan for melanoma skin cancer
Your doctor usually wants you to have a CT or MRI scan if:
- a biopsy shows melanoma in your lymph nodes
- you don’t have melanoma in your lymph nodes but your doctor thinks the melanoma has spread
- you haven’t had a lymph node biopsy but your doctor thinks the melanoma has already spread
You usually have a scan that looks at your:
- chest
- tummy (abdomen) – including the area between your hips, called the pelvis
- head
If your doctor thinks you should have MRI scans instead of CT scans they will talk to you about this. Some people may have a CT scan of their chest, abdomen and pelvis and an MRI scan of their head.
Blood tests
A blood test is where your doctor, nurse or takes a small amount of blood and sends it to the laboratory. Lots of changes in your body show up in blood tests.
You may have blood tests to check your general health, including how well your kidneys and liver are working. Your doctor may also check the number of blood cells. You usually have blood tests if you are having:
- an operation under general anaesthetic to remove melanoma skin cancer
- a CT or
PET-CT scan – this is to check your kidneys are working well and are able to get rid of the special dye (contrast) they use for the scan - targeted cancer drugs, immunotherapy or chemotherapy
Vitamin D
You might have a blood test to check your vitamin D levels. Your skin produces vitamin D when you have been in the sun. It is needed for healthy bones.
Doctors ask people with melanoma skin cancer to protect their skin from the sun. This means they may have lower levels of vitamin D in their body. You can also get vitamin D by eating eggs and oily fish such as mackerel and salmon. But if your Vitamin D level is low, your doctor may ask you to take a vitamin D tablet (supplement).
Other tests
Occasionally your doctor may want you to have other tests. This might include a PET-CT scan. This is a combination of a and a CT scan.
Your doctor will explain what these tests are for and how to prepare for them.
Treatment
The tests you have help your doctor find out if you have melanoma skin cancer and if it has spread. This is called the stage of a cancer. This is important because doctors recommend your treatment according to the stage.
Coping with melanoma skin cancer
Coping with a diagnosis of melanoma skin cancer can be difficult. There is help and support available for you and your family.
