Melanoma is a rare and serious type of cancer that begins in the skin and can spread to other organs in the body.
The most common sign of melanoma is the appearance of a new moleor a change in an existing mole. This can happen anywhere on the body, but the back, legs, arms and face are most commonly affected.
In most cases, melanomas have an irregular shape and more than one colour. They may also be larger than normal moles and can sometimes be itchy or bleed.
An "ABCDE checklist" has been developed for people to tell the difference between a normal mole and a melanoma. Watch a visual guide to moles.
Why does melanoma happen?
Melanoma happens when some cells in the skin begin to develop abnormally. It is thought that exposure to ultraviolet (UV) light from natural or artificial sources may be partly responsible.
Certain things can increase your chances of developing melanoma, such as having:
lots of moles or freckles
pale skin that burns easily
red or blonde hair
a family member who has had melanoma
See your GP if you notice any change to your moles. Your GP will refer you to a specialist clinic or hospital if they think you have melanoma.
In most cases, a suspicious mole will be surgically removed and studied to see if it is cancerous. This is known as a biopsy.
You may also have a test to check if melanoma has spread elsewhere in your body. This is known as a sentinel node biopsy.
How is melanoma treated?
The main treatment for melanoma is surgery, although your treatment will depend on your circumstances.
If melanoma is diagnosed and treated at an early stage, surgery is usually successful.
If melanoma isn't diagnosed until an advanced stage, treatment is mainly used to slow the spread of the cancer and reduce symptoms. This usually involves medicines, such as chemotherapy.
Once you have had melanoma, there is a chance it may return. This risk is increased if your cancer was widespread and severe.
If your cancer team feels there is a significant risk of your melanoma returning, you will probably need regular check-ups to monitor your health. You will also be taught how to examine your skin and lymph nodes to help detect melanoma if it returns.
Who is affected
Melanoma is relatively rare, but is becoming more common. There are currently around 13,000 new cases diagnosed each year in the UK.
Melanoma is one of the most common cancers in people aged 15-34 and more than a third of cases occur in people under 55. More than 2,000 people die every year in the UK from melanoma.
Can melanoma be prevented?
Melanoma is not always preventable, but you can reduce your chances of developing it by limiting your exposure to UV light.
You can help protect yourself from sun damage by using sunscreen and dressing sensibly in the sun. Sunbeds and sunlamps should also be avoided.
Regularly checking your moles and freckles can help lead to an early diagnosis and increase your chances of successful treatment.
Symptoms of melanoma
The first sign of a melanoma is often a new mole or a change in the appearance of an existing mole.
Normal moles are usually round or oval, with a smooth edge, and no bigger than 6mm (1/4 inch) in diameter.
See your GP as soon as possible if you notice changes in a mole, freckle or patch of skin, especially if the changes happen over a few weeks or months.
Signs to look out for include a mole that is:
bleeding or becoming crusty
itchy or painful
A helpful way to tell the difference between a normal mole and a melanoma is the ABCDE checklist:
Asymmetrical – melanomas have two very different halves and are an irregular shape.
Border – melanomas have a notched or ragged border.
Colours – melanomas will be a mix of two or more colours.
Diameter – melanomas are larger than 6mm (1/4 inch) in diameter.
Enlargement or elevation – a mole that changes size over time is more likely to be a melanoma.
Melanomas can appear anywhere on your body, but they most commonly appear on the back, legs, arms and face. They may sometimes develop underneath a nail.
In rare cases, melanoma can develop in the eye. Noticing a dark spot or changes in vision can be signs, although it is more likely to be diagnosed during a routine eye examination.
Want to know more?
Cancer Research UK: Melanoma symptoms.
Causes of melanoma
Most skin cancer is caused by ultraviolet (UV) light damaging the DNA in skin cells. The main source of UV light is sunlight.
Sunlight contains three types of UV light:
ultraviolet A (UVA)
ultraviolet B (UVB)
ultraviolet C (UVC)
UVC is filtered out by the Earth's atmosphere, but UVA and UVB damage skin over time, making it more likely for skin cancers to develop. UVB is thought to be the main cause of skin cancer.
Artificial sources of light, such as sunlamps and tanning beds, also increase your risk of developing skin cancer.
Repeated sunburn, either by the sun or artificial sources of light, increases the risk of melanoma in people of all ages.
You are at an increased risk of melanoma if you have lots of moles on your body, especially if they are large (over 5mm) or unusually shaped.
Having just one unusually shaped or very large mole increases your risk of melanoma by 60%.
For this reason, it's important to monitor moles for changes and avoid exposing them to the sun.
Research suggests that if you have two or more close relatives who have had non-melanoma skin cancer, your chances of developing the condition may be increased.
Certain things are believed to increase your chances of developing all types of skin cancer, including:
pale skin that does not tan easily
red or blonde hair
a large number of freckles
an area of skin previously damaged by burning or radiotherapy treatment
a condition that suppresses your immune system – such as HIV
medicines that suppress your immune system (immunosuppressants) – commonly used after organ transplants
exposure to certain chemicals – such as creosote and arsenic
a previous diagnosis of skin cancer
Want to know more?
Cancer Research UK: Melanoma risks and causes.
A diagnosis of melanoma will usually begin with an examination of your skin. Your GP will refer you to a specialist if they suspect melanoma.
Some GPs take digital photographs of suspected tumours so they can email them to a specialist for assessment.
As melanoma is a relatively rare condition, many GPs will only see a case every few years. It's important to monitor your moles and return to your GP if you notice any changes. Taking photos to document any changes will help with diagnosis.
Seeing a specialist
You will be referred to a dermatology clinic or hospital for further testing if melanoma is suspected. You should see a specialist within two weeks of seeing your GP.
The dermatologist or plastic surgeon will examine the mole and the rest of your skin. They may also remove the mole and send it for testing (biopsy) to check whether the mole is cancerous. A biopsy is usually carried out under local anaesthetic, meaning the area around the mole will be numbed and you won't feel any pain.
If cancer is confirmed, you will usually need a further operation, most often carried out by a plastic surgeon, to remove a wider area of skin.
Further tests will be carried out if there is a concern the cancer has spread into other organs, bones or your bloodstream.
Sentinel lymph node biopsy
If melanoma spreads, it will usually begin spreading through channels in the skin (called lymphatics) to the nearest group of glands (called lymph nodes). Lymph nodes are part of the body’s immune system, helping to remove unwanted bacteria and particles from the body.
Sentinel lymph node biopsy is a test to determine whether microscopic amounts of melanoma (less than would show up on any X-ray or scan) might have spread to the lymph nodes. It is usually carried out by a specialist plastic surgeon, while you are under general anaesthetic.
A combination of blue dye and a weak radioactive chemical is injected around your scar. This is usually done just before the wider area of skin is removed. The solution follows the same channels in the skin as any melanoma.
The first lymph node this reaches is known as the “sentinel” lymph node. The surgeon can locate and remove the sentinel node, leaving the others intact. The node is then examined for microscopic specks of melanoma (this process can take several weeks).
If the sentinel lymph node is clear of melanoma, it's extremely unlikely that any other lymph nodes are affected. This can be reassuring because if melanoma spreads to the lymph nodes, it's more likely to spread elsewhere.
If the sentinel lymph node contains melanoma, there is a risk that other lymph nodes in the same group will contain melanoma.
Your surgeon should discuss the pros and cons of having a sentinel lymph node biopsy before you agree to the procedure. Sentinel lymph node biopsy does not cure melanoma, but is used to investigate the outlook of your condition.
An operation to remove the remaining lymph nodes in the group may be recommended. This is known as a completion lymph node dissection or completion lymphadenectomy.
Other tests you may have include:
a computerised tomography (CT) scan
a magnetic resonance imaging (MRI) scan
a positron emission tomography (PET) scan
Want to know more?
Cancer Research UK: Melanoma tests.
Cancer Research UK: Further tests for melanoma.
Surgery is the main treatment for melanoma, although it often depends on your individual circumstances.
People with melanoma skin cancer should be cared for by a team of specialists that often includes a dermatologist, a plastic surgeon, an oncologist (a radiotherapy and chemotherapy specialist), a pathologist and a specialist nurse.
When helping you decide on your treatment, the team will consider:
the type of cancer you have
the stage of your cancer (how big it is and how far it has spread)
your general health
Your team will recommend what they believe to be the best treatment option, but the final decision will be yours.
Before going to hospital to discuss your treatment options, you may find it useful to write a list of questions to ask the specialist. For example, you may want to what the advantages and disadvantages of particular treatments are.
Health professionals use a staging system to describe how far melanoma has grown into the skin (the thickness) and whether it has spread. The type of treatment you receive will depend on what stage the melanoma has reached.
The stages of melanoma can be described as:
Stage 0 – the melanoma is on the surface of the skin.
Stage 1A – the melanoma is less than 1mm thick.
Stage 1B – the melanoma is 1-2mm thick, or the melanoma is less than 1mm thick and the surface of the skin is broken (ulcerated) or its cells are dividing faster than usual (mitotic activity).
Stage 2A – the melanoma is 2-4mm thick, or the melanoma is 1-2mm thick and is ulcerated.
Stage 2B – the melanoma is thicker than 4mm, or the melanoma is 2-4mm thick and ulcerated.
Stage 2C – the melanoma is thicker than 4mm and ulcerated.
Stage 3A – the melanoma has spread into one to three nearby lymph nodes, but they are not enlarged; the melanoma is not ulcerated and has not spread further.
Stage 3B – the melanoma is ulcerated and has spread into one to three nearby lymph nodes but they are not enlarged, or the melanoma is not ulcerated and has spread into one to three nearby lymph nodes and they are enlarged, or the melanoma has spread to small areas of skin or lymphatic channels, but not to nearby lymph nodes.
Stage 3C – the melanoma is ulcerated and has spread into one to three nearby lymph nodes and they are enlarged, or the melanoma has spread into four or more lymph nodes nearby.
Stage 4 – the melanoma cells have spread to other areas of the body, such as the lungs, brain or other parts of the skin.
Want to know more?
Cancer Research UK: Treating melanoma.
Cancer Research UK: Stages of melanoma.
Macmillan: Malignant melanoma.
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The best way to prevent all types of skin cancer is to avoid overexposure to the sun.
A few minutes in the sun can help maintain healthy levels of vitamin D, which is essential for healthy bones, but it's important to avoid gettingsunburn.
Once you are burnt, the damage has already been done to your skin, as it has received a dangerous level of radiation. Every time the skin is exposed to radiation, this increases the chance of a cancer occurring, possibly many years in the future.
Some simple steps to manage your sun exposure are outlined below.
Avoid the sun when it is at its hottest
The sun is usually at its hottest between 11am and 3pm, but can also be very strong and have potentially damaging effects at other times.
Do not spend long periods of time in the sun during the day. Make sure you spend time in the shade, and cover up with clothes and sunscreen.
If you cannot avoid spending long periods of time in the sun – for example, if you work outdoors – wear clothes that will provide sun protection.
This should include a hat to protect your face and scalp, and sunglasses to protect your eyes. When buying sunglasses, look for:
the CE or British Standard mark (BS EN 1836: 2005)
a UV 400 label
a label saying the glasses give 100% UV protection
When buying sunscreen, make sure it's suitable for your skin type and blocks both ultraviolet A (UVA) and ultraviolet B (UVB) radiation. A sun protection factor (SPF) of at least 15 is recommended.
Sunscreen should be applied around 15 minutes before you go into the sun and reapplied every two hours. If you are planning to spend time in the water, use a waterproof sunscreen.
Take extra care to protect babies and children. Their skin is much more sensitive than adult skin, and repeated exposure to sunlight could lead to skin cancer developing in later life. Before going out into the sun, make sure your children are dressed appropriately and are wearing a hat and a high SPF sunscreen.
Most health professionals will tell you to avoid sunbathing altogether, because even a tan can increase your risk of developing skin cancer.
However, if you are determined to get a tan, do it gradually by limiting the amount of time you spend in the sun each day and by wearing sunscreen.
When you begin to tan, limit your exposure to the sun to 30 minutes, then gradually increase it by five or 10 minutes a day.
Sunbeds and sunlamps
The British Association of Dermatologists is the UK's leading professional body on skincare. It advises that people should not use sunbeds or sunlamps.
Sunbeds and lamps can be more dangerous than natural sunlight, because they use a concentrated source of ultraviolet (UV) radiation.
UV radiation can increase your risk of developing melanomas. Sunbeds and sunlamps can also cause premature skin ageing.
If you continue to use sunbeds or sunlamps, the Health and Safety Executive (HSE) has issued advice on the health risks linked to UV tanning equipment, which includes sunbeds, sunlamps and tanning booths. It recommends you do not use UV tanning equipment if:
you have fair, sensitive skin that burns easily or tans slowly or poorly
you have a history of sunburn, particularly in childhood
you have lots of freckles or red hair
you have lots of moles
you are taking medicines or using creams that make your skin sensitive to sunlight
you have a medical condition made worse by sunlight
you have had skin cancer or someone in your family has had skin cancer
sunlight has already badly damaged your skin
The HSE's advice also includes important points to consider before you decide to use a sunbed. For example, if you use a sunbed, the operator should advise you on your skin type and how many minutes you should use the machine for.
It is now illegal for under-18s to use sunbeds. The Sunbeds (Regulation) Act, which came into force in April 2011, prevents those under 18 from:
being allowed to use tanning salons and sunbeds at premises, including beauty salons, leisure centres, gyms and hotels
being offered the use of a sunbed
being allowed to be in an area reserved for sunbed users
Check your moles
As well as staying safe in the sun, you should regularly check any moles for signs of melanoma.
See your GP if you notice any changes to your moles or freckles, as this can lead to an early diagnosis and improve your chances of successful treatment.
Want to know more?
Cancer Research UK: SunSmart.
HSE: Reducing health risks from the use of ultraviolet (UV) tanning equipment (PDF, 93kb).