Risk factors and causes of melanoma
The main risk factor for developing melanoma is exposure to UV radiation, through natural sunlight or artificially from sunbeds or lamps.
UV radiation damages the DNA (genetic material) in our skin cells and can cause skin cancers such as melanoma.
A risk factor is something that increases your chance of developing a health condition such as cancer. For example, smoking is the best known risk factor for lung cancer. Having a particular risk factor doesn’t mean you definitely will get cancer, just as people without any known risk factors can develop cancer.
Ultraviolet (UV) radiation from the sun
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In the UK, the number of white people developing melanoma and other skin cancers is steadily rising. The main reason for this is increased sun exposure as a result of sunny holidays. People who experience episodes of sunburn, especially where the skin blisters, are more at risk. It’s important for everyone to be aware of the damage that too much exposure to the sun can cause. However, experts recommend regular exposure to a small amount of sunshine. Sunlight helps our bodies make vitamin D, which keeps our bones and teeth healthy. The amount of exposure you need depends on your hair and skin type. But it’s important not to stay out for long enough to let your skin redden or burn.
Ultraviolet (UV) radiation from sunbeds
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Sunbeds give off artificial UV rays that damage the DNA and increase the risk of developing melanoma. The more you use a sunbed or lamp, and the earlier in life you begin using them, the greater your risk. It’s important to protect yourself from the sun and avoid sunbeds. This is especially true if you’ve had a melanoma (or any other type of skin cancer) or if you’re at an increased risk of melanoma. Although exposure to UV radiation from the sun or sunbeds is the main risk factor for developing melanoma, it’s not the only risk factor. Like other cancers, there are many things that may lead to the development of a melanoma.
Other factors that can increase your risk of getting melanoma
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Your skin type
People with fair skin, red or fair hair, blue eyes and freckles are more sensitive to the sun. Because of their skin type, they burn more easily and so are more at risk of getting melanoma. Having naturally darker (brown or black) skin lowers your risk of getting a melanoma, but it doesn’t mean that you’ll never get one.
Episodes of severe sunburn that cause the skin to blister, especially during childhood, can increase the risk of melanoma in the future. So it’s important that adults and particularly children avoid getting sunburnt.
Having lots of moles and unusual moles
People who have a lot of moles (especially over 100) have a higher risk of getting melanoma. People with moles that are bigger than average, with an irregular shape or colour (called atypical), have an increased risk. These moles (sometimes called dysplastic naevi) rarely change into melanoma, but it’s important to keep an eye on them.
Having lots of moles and atypical moles can run in some families. Having a very large, dark, hairy mole that you were born with also increases your risk of melanoma. If you have lots of moles or unusual moles, you can be referred to a skin specialist for advice and an assessment of your skin.
Family history of melanoma
This increases your risk, especially if you have two or more close relatives who’ve had melanoma. About 5–10% of melanomas are thought to be caused by inherited faulty genes. Some of these faulty genes may also be linked to pancreatic cancer, and this helps explain why some families at risk of melanoma are also at increased risk of pancreatic cancer. People with a very strong family history of melanoma or pancreatic cancer should be referred by their GP to a family cancer clinic.
People with a weakened immune system have an increased risk of melanoma. This could be due to HIV or taking drugs that suppress the immune system (for example, after an organ transplant)