Overexposure to ultraviolet (UV) radiation from the sun or sunbeds is the main cause of skin cancer and it could be prevented through enjoying the sun safely and avoiding sunburn.

What is UV?

There are 2 main types of UV rays that damage our skin. Both types can cause skin cancer:
• UVB is responsible for the majority of sunburns.
• UVA penetrates deeper into the skin. It ages the skin, but contributes much less towards sunburn.

A third type of UV ray, UVC, is the most dangerous of all, but it is completely blocked out by the ozone layer and doesn’t reach the earth’s surface.
Sunbeds give off UVA and UVB, but the mixture of the two is usually different to natural sunlight and the UV is often much stronger.

What is sunburn?

Sunburn is a clear sign that the DNA in your skin cells has been damaged by too much UV radiation. Getting painful sunburn, just once every 2 years, can triple your risk of melanoma skin cancer.
Sunburn doesn’t have to be raw, peeling or blistering. If your skin has gone pink or red in the sun, it’s sunburnt.
Sunburn is caused by UV from the sun. You can’t feel UV rays – the heat from the sun comes from infrared rays, which can’t burn you. This is why people can still burn on cool days.

What happens to my skin when it burns?

Too much UV radiation from the sun or sunbeds can damage the genetic material (the DNA) in your skin cells. If enough DNA damage builds up over time, it can cause cells to start growing out of control, which can lead to skin cancer.
Your body has ways of repairing most of the damage. But it is not perfect – some damaged DNA can be left behind. Your body’s attempt to repair this damage is what causes the painful symptoms of sunburn.
The blood vessels around the sunburnt skin swell, allowing blood to rush into it. This is why sunburn looks red.
Blood inside your body is also hot, which is why it feels like sunburnt skin gives off heat – actually, it is usually no hotter than your core body temperature. The wider blood vessels allow the cells of your immune system to travel to the site of the damage. They also release chemicals which trigger inflammation – this is why bad sunburn is swollen and painful.
Sometimes, the sun damages skin cells so severely that they must be destroyed. Peeling after sunburn is your body’s way of getting rid of damaged cells that could lead to cancer. Although skin peels and new skin layers form, some damage can still remain. So it is important to try to avoid burning in the first place.

What should I do if I get sunburnt?

Getting sunburnt doesn’t mean you will definitely develop skin cancer. But getting sunburnt a lot does mean you have a higher risk of the disease. So if you have had sunburn in the past, it’s a good idea to think about what more you can do to protect your skin next time.
If you notice your skin becoming pink or red, you should come out of the sun and cover up to help stop any more damage from happening. Putting on more sunscreen won’t help and won’t let you safely stay out in the sun for longer.

Enjoy the Sun Safely!

Whatever your age, the best way to enjoy the sun safely and protect your skin from sunburn is to use a combination of shade, clothing and sunscreen. Children and teenagers might need a reminder or a helping hand, but setting a good example yourself is a great way to help them learn and get into good habits.
When the sun is strong or you’re at risk of burning:
• Spend time in the shade between 11am and 3pm.
• Cover up with a t-shirt, hat and sunglasses.
• Use a sunscreen with a protection level of at least SPF15 and 4 stars. Use it generously and reapply regularly.

Who is most at risk of skin cancer?

Anyone can develop skin cancer, but some people are more likely to get the disease than others. These people tend to have one or more of the following:
• Fair skin that burns easily in strong sun
• Lots of moles or freckles
• Red or fair hair
• Light-coloured eyes
• A personal or family history of skin cancer
• A history of sunburn

What if I don’t have fair skin?

People with naturally brown or black skin are much less likely to develop skin cancer. This is because they have more melanin pigment in their skin cells – which helps protect the skin from damaging UV rays. But getting a tan isn’t the same as having naturally darker skin and suntan offers very little protection – at best equivalent to SPF3.
However, skin cancer can still affect people with brown or black skin. It is most common on parts of the body that aren’t often exposed to the sun such as the soles of the feet.

Sunscreen

Sunscreens will not protect us completely from sun damage on their own. However, they can be useful for protecting the parts of skin we can’t shade or cover. This is why we recommend using sunscreens together with shade or clothing to avoid getting too much UV exposure.
Sunscreens with higher factors don’t provide much more protection against UVB radiation. For example, an SPF15 sunscreen filters out 93% of UVB radiation, while an SPF30 sunscreen filters out 96%.
Worryingly, many people burn more frequently when they use higher factors of sunscreen because they stay out in the sun for longer. There is a concern that higher factor sunscreens may lure people into a false sense of security. You should never use sunscreen in order to spend longer in the sun. No sunscreen, no matter how high the factor, can provide 100% protection.

Tips for using sunscreen properly

No sunscreen, whether it’s factor 15 or 50, will give the protection it claims unless you apply it properly.
• Make sure you put enough sunscreen on – people often apply much less than they need to, to get the full protection. When your risk of burning is high, ensure that all exposed skin is thoroughly covered in sunscreen. As a guide this means: Around 2 teaspoonfuls of sunscreen if you’re just covering your head, arms and neck. Around 2 tablespoonfuls if you’re covering your entire body, while wearing a swimming costume
• Reapply sunscreen regularly – it is easily rubbed, sweated or washed off. And reapplying helps avoid missing bits of skin.
• Use sunscreen together with shade and clothing to avoiding getting caught out by sunburn.
• Don’t be tempted to spend longer in the sun than you would without sunscreen.
• Apply to clean, dry skin.
• Even sunscreens that claim to be ‘water resistant’ or ‘waterproof’ should be reapplied after going in the water, especially if you have towelled dry.
• Don’t store sunscreens in very hot places as extreme heat can ruin their protective chemicals.
• Don’t forget to check the expiry date on your sunscreen. Most sunscreens have a shelf life of 2-3 years, but ensure your sunscreen has not expired before you use it.

Source- http://www.cancerresearchuk.org/about-cancer/causes-of-cancer