Skin cancer - melanoma

This section provides information about melanoma. This includes its causes, risk factors, symptoms, how it is diagnosed and the different types of melanoma treatments available.

About melanoma cancer

Melanoma, sometimes called cutaneous malignant melanoma, is a type of skin cancer but, like some other cancers, can spread to other organs in the body.

The common sign of melanoma is the appearance of a new mole or a change to the appearance of an existing mole. This can be anywhere on the body, but is most often found upon the back, legs, arms and face.

Facts about melanoma

• About 13,300 people are diagnosed with melanoma in the UK each year
• Melanoma is one of the most common types of cancer in people between the ages of 15 to 34
• It is the 5th most common cancer overall in the UK, excluding non-melanoma skin cancer.¹

¹ Cancer Research UK, Melanoma risks and causes. https://www.cancerresearchuk.org/about-cancer/melanoma/risks-causes

Types of melanoma cancer

There are several different types of melanoma, though superficial spreading melanoma, nodular melanoma, and lentigo maligna melanoma make up 90% of all diagnosed malignant melanomas.

Acral lentiginous melanoma and a few rare types of melanoma make up the other 10%.² 

Superficial spreading melanoma
70% of all melanomas in the UK are superficial spreading melanomas, which are the most common melanoma in middle-aged people. It tends to grow outwards (called the radial growth phase), though it is not usually at risk of spreading to other parts of the body until it begins to grow downwards into the deeper layers of skin and beyond.³ 

Nodular melanoma
This melanoma type tends to develop quite quickly, and on parts of the body only exposed to the sun occasionally. Nodular melanomas are often dark brownish black in colour with a raised area on the surface of the skin, and are commonly found on the chest or back. The melanoma starts to grow downward and deeper into the skin quickly if it is not removed.⁴ 

Lentigo maligna melanoma
10% of melanomas are lentigo maligna melanomas, and develop from slow growing pigmented areas of skin. They appear in areas of skin that get a lot of sun exposure, so are most common on the face, and are common in much older people who have spent a lot of time outdoors. Lentigo maligna is flat and grows outwards in the surface layers of the skin, so may gradually increase in size and change shape over several years.⁵

Acral lentiginous melanoma
A rare type of melanoma that’s commonly found on the palms of the hands and soles of the feet and toes, or under the toe nails.⁶ 

Amelanotic melanoma
Amelanotic means without melanin, which means that amelanotic melanomas usually have little or no colour, though are sometimes pink or red, and may be light brown or grey at the edges. Less than 5% of melanomas are amelanotic.7 

Other melanoma types
Melanomas can occur anywhere in the body, including the internal organs. It is rare, but melanoma can sometimes grow inside the eye. Melanocytes in the iris and the lining inside the eye (the choroid layer) can become cancerous, leading to a melanoma which may be visible as a dark spot in the iris. It’s also possible to have melanoma of the vulva or the rectum.

² Cancer Research UK, Types of melanoma https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/types
³ Cancer Research UK, Types of melanoma
⁴ Cancer Research UK, Types of melanoma
⁵ Cancer Research UK, Types of melanoma
⁶ Cancer Research UK, Types of melanoma
⁷ Cancer Research UK, Types of melanoma

Causes and risk factors

Melanoma happens because cells in the skin called melanocytes, start to develop abnormally.⁸

Sun exposure
Exposure to ultraviolet (UV) rays from sunlight or artificial light sources is an important risk factor. It has been shown that sun exposure during childhood is particularly linked to development of melanoma and sunbed use is also linked to melanoma. However other factors can increase your risk of developing skin cancers, such as having:

• lots of moles or freckles
• pale or fair skin that burns easily
• blonde or red hair
• a relative who’s had melanoma, or if you’ve previously had a melanoma.

Moles
Some people have more moles than others, and the more you have on your body, the higher your risk of melanoma. This doesn't mean you’ll definitely get melanoma, but it does mean you should be careful about your exposure to the sun.

People with lots of unusually shaped or large moles (called atypical mole syndrome) have a higher risk of melanoma than the general population.

Pale or fair skin
People who are fair skinned, especially people with blonde or red hair, are more at risk of developing melanoma, as are people with lots of freckles. Also, if you have a tendency to get sunburned, you have a greater than average risk of melanoma. Fair skinned people, or people who go red and peel before they tan are also at a higher risk. 

Your family history
If you have a close relative who’s had melanoma, you’re more at risk yourself. This is probably because we tend to share the same sort of colouring and skin type as our close relatives. But even if you have darker skin colouring, you should be careful in the sun, as you still have a slight increase in the risk of developing melanoma.

Also, if you’ve had a melanoma before then your risk of getting a second melanoma increases. Studies show that people who’ve had a non-melanoma skin cancer have about double the risk of melanoma compared to the general population.⁹

Melanoma cancer symptoms and diagnosis

As a rule, if you notice anything unusual on your skin that doesn’t go away in a month, go to see your doctor about the spot or mark.

Perhaps take a photograph of any unusual spots that develop so you can see any changes over time. Keep in mind that there are many skin conditions that are not cancer, especially in older people.

Checking for signs of melanoma
Usually, the signs of melanoma are quite visible. That’s because they occur mostly on skin that’s exposed to the sun.

To help you spot melanoma early, it helps to be aware of how your skin normally looks, so you can recognise any changes more easily.

Get your partner or a close friend to check your back or other areas that you can’t easily see.

Where melanoma develop
Melanoma can develop on or near other non-cancerous (benign) skin growths. You should show your doctor any area of your skin that is damaged and does not heal up.

The symptoms of melanoma may be similar to symptoms of other skin conditions. It is worth having any symptom checked by your GP. Your doctor won’t think you are bothering them for something trivial. They can decide whether your symptoms need to be investigated further.

How melanoma appears
The signs of melanoma are best summarised by the ABCDE criteria They are:-

• Asymmetry
• Border irregular
• Colour irregular
• Diameter more than 6mm
• Elevation - becoming more raised

The most important sign is change over time of colour shape or size.

The stages of melanoma

The tests used to diagnose your melanoma will give some information about the stage, which describes how deep it has grown into the skin, and whether it has spread.

Staging helps consultants to decide on the kind of treatment you need, the risk of a melanoma returning and whether you need any tests to see if the melanoma has spread into any lymph nodes.

Most melanomas are discovered at an early stage when the chance of cure is high. 

Types of melanoma staging systems¹⁰ 
Consultants use a few different systems and scales to describe the different stages of melanoma. The AJCC Staging System gives a stage of 0 to 4. Stage 0 means that the melanoma lies only in the epidermis, which is the upper layer of the skin. It has not become invasive and the likelihood of it returning is very small. The highest stage is 4, which means the melanoma has spread to other organs. In general the higher the stage, the poorer the prognosis.

However the simplest way of telling how likely it is to recur is by the Breslow thickness, which is measured by the pathologist after the biopsy.

The Breslow depth or thickness
This system measures the thickness of the melanoma in the skins using a small ruler called a micrometre. The measure that doctors use is called the primary tumour thickness scale, or the Breslow thickness, and it measures in millimetres (mm) how far the melanoma cells have reached down through the skin from the surface. The deeper the Breslow thickness, the more likely the melanoma is to return.

AJCC stages of melanoma
There are five main stages to the number system, and these are:

• Stage 0 (in situ melanoma): The melanoma cells are only in the top surface layer of skin cells (the epidermis) and have not spread into deeper layers.
• Stage 1A: The melanoma is less than 1mm thick, and the covering layer of skin over the tumour is not ulcerated or broken – it is only in the skin and has not spread elsewhere.
• Stage 1B: The melanoma is less than 1mm thick and the skin is broken (ulcerated), or it is between 1 and 2mm and is not ulcerated – it is only in the skin and has not spread elsewhere.
• Stage 2A: The melanoma is between 1 and 2 mm thick and is ulcerated, or it is between 2 and 4mm and is not ulcerated – it is only in the skin and has not spread elsewhere.
• Stage 2B: The melanoma is between 2 and 4mm thick and is ulcerated, or it is thicker than 4mm and is not ulcerated – it is only in the skin and has not spread elsewhere.
• Stage 2C: The melanoma is thicker than 4mm and is ulcerated, but it is only in the skin and there is no sign that it has spread to lymph nodes or other parts of the body.
• Stage 3A: The melanoma has spread to up to three lymph nodes near the primary tumour, but the nodes are not enlarged and cells can only be seen under a microscope. The melanoma is not ulcerated and has not spread to other areas of the body.
• Stage 3B: The melanoma is ulcerated and has spread to between one and three lymph nodes, but the nodes are not enlarged and the cells can only be seen under a microscope
  OR
  the melanoma is not ulcerated and it has spread to between one and three lymph nodes nearby and the lymph nodes are enlarged
  OR
  the melanoma is not ulcerated, and has spread to small areas of skin or lymphatic channels, but nearby lymph nodes do not contain melanoma cells.
  Stage 3C
  There are melanoma cells in the lymph nodes and small areas of melanoma cells in the skin or lymph channels close to the main melanoma
  OR
  the melanoma is ulcerated and has spread to between one and three lymph nodes nearby which are enlarged
  OR
  the melanoma may or may not be ulcerated and has spread to four or more nearby lymph nodes
  OR
  the melanoma may or may not be ulcerated and has spread to lymph nodes that have joined together.
• Stage 4: At this stage melanomas have spread elsewhere in the body, far away from where they started (the primary site) and the nearby lymph nodes. The most common places for melanoma to spread are the lung, liver or brain, or to distant lymph nodes or other areas of the skin.

It’s important to note that, in the UK, most melanomas are early stage 1 and surgery is usually very effective – this is also the case for stage 2 tumours.

¹⁰ Cancer Research UK, Stages of melanoma https://www.cancerresearchuk.org/about-cancer/melanoma/stages-types/types

Melanoma cancer treatment

If you’ve been diagnosed with melanoma it should be surgically removed with a narrow margin under a local anaesthetic to confirm the diagnosis. If melanoma is confirmed the scar will then have to be re-excised to ensure that no tumour cells remain. The amount of skin that is removed during the re-excision will depend on the pathology from the first biopsy.

Other tests and treatment may be required depending on the initial findings and other symptoms but these will be different for each person.

Benefits of skin cancer treatment 
The best chance of curing a melanoma is to cut it out as early as possible. The longer the delay in removing it the greater the chance that it will spread.

Paying for your treatment 
You have two options to pay for your treatment – your costs may be covered by your private medical insurance, or you can pay for yourself.

Check with your private medical insurer to see if your diagnostic costs are covered under your medical insurance policy.

If you are paying for your own treatment the cost of the procedure will be explained and confirmed in writing when you book the operation.

Ask the hospital for a quote beforehand, and ensure that this includes the consultants’ fees and the hospital charge for your procedure.

Want to know more?
If you’d like to read more about skin cancer, melanoma treatment or protecting against skin cancer, please visit nhs.uk.