UV radiation causes cancers of the skin—the most common cancers
Ultraviolet (UV) radiation is a major risk factor for melanoma of the skin. About 230,000 cases and 55,000 deaths from melanoma are estimated to occur each year worldwide. UV radiation also causes keratinocyte (also known as nonmelanoma) skin cancers, the most common types of cancer in humans with about 13 million cases each year. While rarely fatal, keratinocyte cancers impose a significant burden of morbidity and economic cost.
The major source of UV radiation is the sun. The amount of solar radiation reaching any point on the Earth’s surface depends on latitude and altitude, time of day and year, cloud cover, and air pollution; UV radiation levels also depend on the protective stratospheric ozone layer.
Personal exposures to “artificial” UV radiation up to 10–15 times stronger than summer midday sun in Southern Europe may occur through the use of tanning devices. Although classified as a human carcinogen, they have been commonly used for cosmetic purposes.
Both boys and girls in some countries use sunbeds, which increases the risk of developing skin cancer later in life.
Prevalence of sunbed use among youth (Prevalence = use at least once in past 12 months)Download High Res Text alternative: Prevalence of sunbed use among youth
The risk is also higher with high UV radiation exposure in childhood.
In addition to ambient UV radiation and occupational and recreational sun exposure, other risk factors for skin cancer are fair skin color and sensitivity to the sun, which are inherited characteristics. People with innately dark skin have very low rates of skin cancer; those with light skin and hair, blue or green eyes, and many moles have much higher rates. The risk is also higher with high UV radiation exposure in childhood.
Sunscreens protect skin against UV radiation, but are only part of a sun-safe strategy, which also includes wearing sunglasses, hats and protective clothing; staying out of the sun in the middle part of the day; and providing effective shade structures for outdoor venues. Since 1983, Australia has been implementing skin cancer prevention campaigns based on this strategy. While it will take many years to witness the full effects of this program, rates of melanoma are already decreasing among youth.
“Support and education for sun protection are necessary from all aspects of society: families, healthcare systems, schools, worksites, community organizations, and the mass media.”