UV radiation

Internationally, estimates of the percentage of cancer caused by ultraviolet (UV)/ionising radiation range from 2% in the United States²,³ to 8–10% of cancer cases in European men.¹⁶,⁵⁷ According to WHO, there were 65,000 melanoma-related deaths internationally in 2000.¹

UV radiation and cancer in Australia

International statistics likely underestimate the effect of UV radiation in Australia, which has the highest rate of skin cancer in the world.²⁰ The age-standardised incidence rate of melanoma in Australia in 2008 was more than 12 times than the average global rate.²⁰ Sun exposure has been estimated to cause around 95% of melanoma cases in areas of high exposure, such as Australia,⁷¹ and around 99% of non-melanoma skin cancers in Australia.⁷² Non-melanoma skin cancer (including basal cell carcinoma and squamous cell carcinoma) is the largest cause of hospitalisation from cancer in Australia⁷³ and around two in three Australians acquire at least one non-melanoma skin cancer by the age of 70 years.⁷⁴ Exposure to UV radiation, particularly during childhood and adolescence, is identified as the greatest risk factor for non-melanoma skin cancer.⁷³

The National Sun Protection Survey 2010–11 indicates improvements in Australian attitudes regarding skin cancer prevention and protective behaviours.⁷⁵ Of those surveyed, 13% of adults and 21% of adolescents were sunburnt on a typical summer weekend, compared to the 2003–04 survey results of 18% and 25% respectively.⁷⁵ In the 2010–11 survey, 36% of adults and 37% of adolescents reported using sunscreen while outdoors.⁷⁵

UV radiation and cancer

A 2012 IARC Monograph on radiation classified UV radiation as a Group 1 carcinogen, which causes melanoma and other types of skin cancer, including basal cell carcinoma and squamous cell carcinoma.⁶ The IARC Monograph identified a positive association with lip cancer and cancer of the eye (conjunctival squamous cell carcinoma and ocular melanoma).⁶ A systematic review in 2001 reported that melanoma risk may increase with cumulative sun exposure, and especially repeat burning and blistering.⁷⁶

UV-emitting solaria and cancer

UV-emitting tanning devices (solaria) have also been classified as Group 1 carcinogens by the IARC, with evidence that these devices cause melanoma of the skin and eye, and are positively associated with squamous cell skin carcinoma.⁶ An increased melanoma risk is associated with solaria use before the age of 30.⁶

All Australian jurisdictions, except the Northern Territory and Western Australia, have introduced legislation to ban commercial solaria tanning units from 1 January 2015.⁷⁸ There are no solaria currently operating in the Northern Territory, ⁷⁸ and Western Australia is reported to be committed to banning the commercial use of solaria.⁷⁹

Reducing individual risk of cancer and staying healthy

Australian programs to reduce UV exposure and promote use of sunscreen and protective attire have changed attitudes regarding tanning and increasing protective behaviours,³,⁷⁵,⁸⁰ and there has been a decrease in sunburn amongst both adolescents and adults.⁷⁵,⁸¹

Five sun protection behaviours are advised for Australians: to seek shade, wear sun protective clothing, put on a broad-brimmed hat, wear wrap-around sunglasses and to apply SPF30+ or higher sunscreen. It is also advised that sunbeds and solaria also emit UV radiation, so to be aware of the risks associated with tanning.

Cancer Australia recommendations for individuals

Cancer Australia recommends avoiding excessive sun exposure and solaria, and wearing sunscreen and protective clothing to lower risk of skin cancer.

Table 6: Summary of evidence for UV radiation and cancer sites

Risk factor	Source	Evidence	Cancer site
UV radiation	IARC 20126	Sufficient evidence (highest IARC classification of carcinogenicity)	Melanoma,  basal cell carcinoma of the skin, squamous cell carcinoma of the skin
		Limited evidence (positive association)	Lip, conjunctival squamous cell carcinoma, ocular melanoma
UV-emitting tanning devices	IARC 20126	Sufficient evidence (highest IARC classification of carcinogenicity)	Melanoma of the skin and eye
		Limited evidence (positive association)	Squamous cell skin carcinoma

See Appendix 1 for explanation of evidence.