Skin cancer - risk factors

Skin cancer is one of the most common cancers, and it is also one of the most preventable. The main cause is exposure to ultraviolet (UV) radiation from the sun. Regardless of skin type, everyone is at risk of sun damage and skin cancer.

Many people will be diagnosed with skin cancer in their lifetime, and many die from it each year, even though it is largely preventable. Every extra decade of high UV exposure further increases your risk of melanoma, the most dangerous form of skin cancer.

UV radiation and skin cancer#

A small amount of sun helps the body make vitamin D, but too much UV can cause sunburn, premature ageing, eye damage and skin cancer.

UV levels are most intense during the middle of the day, and in some regions and seasons they can be very high, especially where skies are clear. When the UV index is 3 or above, use a combination of sun protection measures — covering clothing, a broad-brimmed hat, sunscreen, sunglasses and shade — whenever you are outdoors.

Skin cells in the top layer of skin (the epidermis) produce a pigment called melanin, which gives skin its natural colour. When skin is exposed to UV radiation, more melanin is produced and the skin darkens. This is a tan. A tan is not a sign of good health but of skin cells in trauma, and tanning can contribute to DNA damage, premature skin ageing and skin cancer.

Every time skin is exposed to the sun, the total lifetime dose of UV radiation increases. Over time this damage adds up, even when no sunburn occurs. All types of sunburn, serious or mild, can cause permanent and irreversible skin damage that can lead to skin cancer later in life. For this reason, everyone, regardless of skin type, should use a combination of sun protection measures whenever the UV index is 3 or above.

Family history and skin type#

Family history and hereditary factors, particularly within your immediate family, play an important part in the risk of developing skin cancer. If one or both of your parents have had a skin cancer, you could be at risk too, especially as you are likely to have a similar skin type.

When combined with UV exposure, the following traits are genetic risk factors for skin cancer:

• red or blonde hair
• light-coloured eyes
• fair, sun-sensitive skin
• a tendency to freckle

People with fair skin are at higher risk than people with very dark skin. If you have fair skin, teach your children the importance of sun protection and help them develop good habits from an early age — this is the best way to reduce their risk of skin damage and skin cancer later in life.

The melanin in very dark skin offers some protection against UV radiation, so the risk of skin cancer is lower. However, when skin cancer is found in people with naturally very dark skin, it is often detected at a later, more dangerous stage, when the risk of death is higher.

Moles, freckles and checking your skin#

No matter what their skin type, everyone should become familiar with their own skin. Check all of your skin, not just sun-exposed areas. If you notice anything unusual, including any change in the shape, colour or size of a spot, or a new spot, see your doctor promptly.

Most people have moles and freckles. But if you have lots of them, you are at higher risk of skin cancer. Have your doctor check any unusual changes as soon as possible, including new spots and any moles or freckles that grow, change shape, change colour, bleed or ulcerate.

Age#

Melanoma is more common in older adults, but skin cancer can occur in young people too. Although early-onset melanoma is rarer, melanoma is one of the most common cancers and a leading cause of cancer death in younger people. Every extra decade of high sun exposure increases your risk, and limiting UV exposure at any age can help reduce it.

Reducing your skin cancer risk#

You can take steps to reduce your risk of skin cancer from UV radiation. When the UV index is 3 or above, use a combination of the five sun protection measures:

• Slip on sun-protective clothing that covers as much skin as possible.
• Slop on SPF50+ broad-spectrum, water-resistant sunscreen. Apply it 20 minutes before going outdoors and reapply every 2 hours, even if the label states it is water-resistant for longer. Never use sunscreen on its own or to extend your time in the sun.
• Slap on a broad-brimmed hat that protects the face, head, neck and ears.
• Slide on wrap-around sunglasses that meet a recognised sun-protection standard. Eye protection is worth using all year round.
• Seek shade, especially during the middle of the day.

Check the daily UV forecast for your area, and use sun protection whenever the UV index is 3 or above.

Winter activities such as skiing and snowboarding also carry a high risk of skin damage and sunburn. UV radiation is more intense at high altitude than at sea level, because the air is clearer and there is less atmosphere to absorb harmful UV rays.

Key points#

• The main cause of skin cancer is exposure to ultraviolet (UV) radiation from the sun.
• Skin cancer is common but is one of the most preventable cancers.
• Every extra decade of high UV exposure further increases your risk of melanoma, the most dangerous form of skin cancer.
• A little sun helps the body make vitamin D, but too much UV can cause skin cancer.
• People with fair skin are at higher risk than people with very dark skin, but everyone is at risk and should use sun protection.