Running behind a tourist: leisure-related skin cancer prophylaxis
Funding for publication of this supplement was provided by the European Skin Cancer Foundation (ESCF).
Conflicts of interest
The most important risk factor in the development of skin cancer is exposure to ultraviolet (UV) radiation. Cumulative lifetime UV radiation exposure has been shown to be most important in the pathogenesis of squamous cell carcinoma, whereas intermittent high-dose UV radiation exposure in childhood and adolescence may be more important in the aetiology of basal cell carcinoma and cutaneous malignant melanoma. Using established methodology and best available estimates on UV-related mortality and morbidity, it has been estimated that annually around 1·5 million disability-adjusted life years are lost through excessive exposure to UV radiation. Skin cancer is a significant health problem and its burden is such that it causes the health system more to treat than any other forms of cancer. Prevention is the key action in managing skin cancer at a population level. Investment in prevention programmes such as SunSmart encourages protective behaviours that will reduce the human and financial costs of skin cancer.
Skin cancers are the most commonly diagnosed type of cancers in white-skinned populations. They are typically grouped into two types, cutaneous malignant melanoma (CMM) and nonmelanoma skin cancers (NMSCs). The incidence of both CMM and NMSCs has continued to rise over the last decade. Currently, between 2 and 3 million NMSCs and 132 000 CMMs occur globally each year. One in every three cancers diagnosed is a skin cancer. As ozone levels have been depleted, the atmosphere has lost a proportion of its protective filter function and increasing levels of solar ultraviolet (UV) radiation reach the Earth’s surface. It is estimated that a 10% decrease in ozone levels will result in an additional 300 000 NMSC and 4500 CMM cases, although it appears that the ozone layer may now be repairing itself and is expected to get back to ‘normal’ range within decades.1
UV radiation, from sun exposure and suntanning equipment use, in both the UVA and UVB spectra, is the main aetiological factor in the development of skin cancer.2 Everyone is exposed to UV radiation from the sun and many artificial sources used in industry, commerce and recreation. UV radiation is a form of radiation given out by the sun. Unlike other forms of solar radiation, such as light and heat, UV radiation cannot be seen or felt. The UV region covers the wavelength range 100–400 nm and is arbitrarily divided into three bands: UVA (315–400 nm), UVB (280–315 nm) and UVC (100–280 nm). All UVC, and approximately 90% UVB, radiation is absorbed by the ozone, water vapour, oxygen and carbon dioxide in our atmosphere. UVA radiation is less affected by the atmosphere. Therefore, the UV radiation reaching the Earth’s surface is largely composed of UVA with a small UVB component.
UV radiation levels are influenced by the following:3 (i) Sun elevation: the higher the sun in the sky, the higher the UV radiation level. Thus, UV radiation levels vary with time of the day and time of the year. The highest levels occur around midday (solar noon) which is when the sun is at its maximum elevation during the summer months. (ii) Latitude: UV radiation levels are higher closer to the equator. (iii) Altitude: a thinner atmosphere at higher altitudes absorbs less UV radiation. With every 1000 m increase in altitude, UV radiation levels increase by 10–12%. (iv) Cloud cover: UV radiation levels are highest under cloudless skies but even with cloud cover, UV radiation levels can be high. Scattering can have the same effect as the reflectance by different surfaces and thus increase total UV radiation levels. (v) Ozone: ozone absorbs some UV radiation that would otherwise reach the earth. While ozone levels vary during the day and with the season, other factors such as sun height and changes in cloud cover appear to have more influence on levels of UV radiation. (vi) Ground reflection: UV radiation is reflected or scattered to varying extents by different surfaces, e.g. fresh snow can reflect as much as 80% of UV radiation, dry beach sand about 15% and sea foam about 25%.
Reduction of skin exposure to UV radiation has been recommended by the World Health Organization to reduce skin cancer rates. This has been addressed through a number of strategies including decreasing individual exposure by encouraging change in behaviour (avoiding sun in the middle of the day, use of shade, hat and clothing use, and sunscreens), along with structural planning, reducing community exposure and reducing ambient sun exposure levels.
Australia has among the highest incidence and mortality rates for skin cancer in the world.4 This is due in part to the high ambient solar UV levels, combined with a predominantly susceptible fair-skinned population. With a population of just over 22 million, over 1800 Australians die from skin cancer each year.5 At least two in three Australians will be diagnosed with skin cancer before the age of 70 years and over 400 000 Australians are treated for skin cancer each year.6,7 The incidence and mortality rates from CMM in Australia are between 2 and 5 times those found in Canada, the U.S.A. and the U.K.8 CMM is the fourth most common cancer in Australia (after prostate, colorectal and breast cancer, but now ahead of lung cancer), with over 10 000 new cases diagnosed each year.9 The combination of very high skin cancer rates with high general practitioner visits (> 1 million p.a.) results in skin cancer being the cancer posing the most costly burden on the Australian health system.7,10
Since 1980, Australians have been exposed to public education media campaigns raising awareness of skin cancer prevention. In the early days, it started with the slogan ‘Slip! (slip on a shirt), Slop! (slop on some sunscreen), Slap! (slap on a hat)’. Over time, two new messages were added to the slogan, ‘Seek! (seek shade)’ and ‘Slide! (slide on some sunglasses)’. An animated seagull character with a catchy jingle was featured with the initial slogan. This campaign was able to penetrate the consciousness of Australians, reminding them of the importance of skin cancer prevention.11 In 1987, a broad-based multifaceted programme was developed with the support of government funding (Victorian Health Promotion Foundation) called SunSmart.
The SunSmart programme tries to influence the knowledge, attitudes and intentions of individuals, along with social and cultural norms in an attempt to promote sun-protection behaviour. The programme aims to increase public awareness of the link between sun exposure and skin cancer through education, settings-based interventions and public communication. It also attempts to change the desirability of a tan. The SunSmart programme has conducted activities across a broad range of settings including schools, community groups, leisure facilities, workplaces and child care centres.
The Cancer Councils across Australia have worked very closely with the Bureau of Meteorology to promote a solar UV index along the guidelines issued by the World Health Organization. The UV index is an international standard measurement of how strong UV radiation from the sun is at a particular place on a particular day. The UV index ranges from 0 to 11+ and the higher the number the greater the risk of skin and eye damage. The SunSmart UV Alert is a tool that can be used to determine when it is necessary for individuals to protect themselves from UV radiation and when sun protection is not required. The SunSmart UV Alert times are issued throughout the year by the Bureau of Meteorology when the UV index is forecast to reach 3 or above. The general rule of thumb for sun protection is as follows (e.g. for Victoria, Australia): from September to April, the UV index forecast for the day is usually 3 or above; at this level, UV radiation can damage your skin and eyes and sun protection is required. From May to August, UV radiation levels are generally low (1 or 2) in Victoria. Sun protection is not needed unless you are in alpine areas or near highly reflective surfaces such as snow or water. The Bureau of Meteorology issues the UV Alert for alpine areas.
When the UV index reaches 3 and above, the following five steps are recommended for protection against sun damage. (i) Slip on some protective clothing. (ii) Slop on sun protection factor (SPF) 30+ sunscreen – make sure it is broad spectrum and water resistant. Apply 20 min before you go outdoors and re-apply every 2 h. (iii) Slap on a hat. (iv) Seek shade. (v) Slide on some sunglasses – make sure they meet Australian Standards.
Slip on some protective clothing
Clothes can protect the skin against the sun’s harmful UV rays. All fabrics disrupt UV radiation to some degree. The current recommendation is to choose clothing that covers as much skin as possible. The UV protection factor (UPF) is a rating designation for sun-protective textiles and clothing. Unlike the SPF that in effect measures only UVB protection, the UPF measures both UVA and UVB. The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) have been performing measurements on fabrics since the early 1980s. Testing methods developed by ARPANSA were adopted by the Australian Standard: Sun Protective Clothing – Evaluation and Classification (AS/NZS 4399:1996). This standard was released in July 1996 to introduce a standardized UPF testing method and it also specifies appropriate wording to be placed on labels of clothing claiming to offer sun protection.12
Factors that contribute to the UPF rating of a fabric are: (i) composition of the yarns (cotton, polyester etc.); (ii) tightness of the weave or knit (tighter improves the rating); (iii) colour (darker colours are generally better); (iv) stretch (more stretch lowers the rating); (v) moisture (many fabrics have lower ratings when wet); (vi) condition (worn and faded garments may have reduced ratings); and (vii) finishing (some fabrics are treated with UV-absorbing chemicals).
UPF ratings and protection categories are shown in Table 1.
Table 1. Ultraviolet (UV) protection factor (UPF) ratings and protection categories
|25, 30, 35||Very good||96·0–97·4|
|40, 45, 50, 50+||Excellent||97·5 or more|
Slop on sun protection factor 30+ sunscreen
Sunscreen has been proven to reduce risk of CMM13 and NMSC. When using sunscreen for sun protection, members of the public are urged to remember the following. (i) Never rely solely on sunscreen alone as no sunscreen provides full protection. (ii) Choose an SPF 30+ sunscreen that is broad spectrum and water resistant. Standards Australia has put forward a proposal that would raise the SPF from 30+ to 50+. In addition, it has proposed new broad-spectrum requirements (1/3 ratio for UVA and a critical wavelength test) plus 4-h water resistancy requirements, making a very high standard product. The draft standard is expected to take effect by summer 2012. (iii) Apply sunscreen generously and evenly to clean, dry skin 20 min before going out into the sun. The average-sized adult should apply more than half a teaspoon of sunscreen (about 3 mL) to each arm and the face/neck (including ears), and just over one teaspoon (6 mL) to each leg, the front of the body and the back of the body. That is 35 mL of sunscreen for one full-body application. (iv) Re-apply all sunscreens every 2 h, or more often when sweating. (v) Check and follow the ‘use by’ date stated on the packaging. (vi) Keep sunscreen below 30 °C.
Sunscreen formulas and their components are regulated through the Therapeutic Goods Administration (TGA). In early 2009, the TGA conducted an updated review of the scientific literature in relation to the use of nanoparticulate zinc oxide and titanium dioxide in sunscreen.14 The TGA review reached the following conclusions. (i) The potential for titanium dioxide and zinc oxide nanoparticles in sunscreens to cause adverse effects depends primarily upon the ability of the nanoparticles to reach viable skin cells. (ii) To date, the current weight of evidence suggests that titanium oxide and zinc oxide nanoparticles do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer (stratum corneum) of the skin that is composed of nonviable, keratinized cells. (iii) There is evidence from isolated (in vitro) cell experiments that zinc oxide and titanium dioxide may induce free radical formation in the presence of light and this free radical generation may cause cell damage (photogenotoxicity with zinc oxide). However, recent work suggests that the photogenotoxicity seen in these studies (with zinc oxide) may be due to UV-induced experimental artifact in an in vitro assay, rather than the presence of the nanoparticles.15
Many sunscreens tend to use ‘microfine’ or ‘micronized’ particles, which are larger than nanoparticles. Nanoparticles are smaller than 100 nm and invisible to the human eye: 1 nm = 0·000001 mm. Microfine particles are smaller than those used in conventional white zinc sunscreens, but are larger than nanoparticles – usually in the range of 100–2500 nm.
Slap on a hat
Broad-brimmed and bucket hats provide the most UV radiation protection for the face and head. Legionnaire-style hats also provide good UV radiation protection. Baseball caps do not protect the head and face.16 Wearing a hat with a brim that shades the eyes can reduce UV radiation to the eyes by up to 50%.17 The brim width on hats should be at least 6 cm and provide the face, neck and ears with plenty of shade. When choosing a hat, it is advised that one considers the following factors. (i) The quality of sun protection it offers. (ii) The type of fabric it is made from – a tighter fabric suture is best. (iii) The fabric’s UPF label – fabric with UPF15 offers good protection while UPF50 offers excellent protection. It is important that buyers ensure the hat’s overall design is effective too. (iv) Whether it is practical (i.e. easy to keep on and does not interfere with activities). (v) Fashion trends (so that the wearer chooses the hat over less protective ones). (vi) Safety. (vii) Ventilation (especially if the hat is used during physical activity or in warmer weather).
Shade is a practical, user-friendly form of sun protection. The most effective shade can reduce UV exposure by over 90% but this only occurs when exposure to the skin is eliminated. Typical shade, such as a tree or umbrella, can reduce UV exposure by up to 75%. This means that 25% or more of UV still reaches the skin from reflection off the sky or surrounding surfaces. Shade can be natural, man-made or a combination of both. It can be permanent, temporary or portable. As a rule of thumb, if the sky can be seen though the shade covering, the skin is less than fully protected. For the most effective UV protection, shade should be combined with protective clothing, a broad-brimmed hat, sunglasses and SPF 30+ sunscreen.
SunSmart recommends outdoor spaces to include the following. (i) Sufficient shade to protect all people when the UV index reaches 3 and above. (ii) Shade that offers at least 94% block-out of direct UV and minimizes indirect UV. (iii) A combination of built and natural shade. Built shade structures provide predictable, reliable coverage, while natural shade is aesthetically pleasing and environmentally friendly. Deciduous trees offer the added benefit of providing cool, UV-protective shade when required and dropping leaves in winter, allowing sunlight to warm and brighten outdoor spaces. (iv) Shade that is easily accessible, attractive, in good condition and regularly maintained.
Slide on some sunglasses
Acute effects of UV radiation on the eyes include photokeratitis and photoconjunctivitis. These effects are reversible, easily prevented by protective eyewear and are not associated with any long-term damage. Chronic effects of UV radiation include cataracts, pterygium, squamous cell carcinoma of the cornea or conjunctiva and ocular melanoma.18–25
To protect the eyes from UV radiation, the Cancer Council Victoria recommends sunglasses that are close fitting, wrap around and cover as much of the eye as possible, meet Australian Standard 1067:2003 (Sunglasses: Category 2, 3 and 4) and are marked EPF (eye protection factor) 10.
In 2003, Standards Australia issued a joint Australian/New Zealand Standard AS/NZS 1067:2003: Sunglasses and Fashion Spectacles, which set limits on the allowed transmittances of fashion spectacles and sunglasses. All sunglasses sold in Australia must be labelled according to this standard. Wearing sunglasses that meet the standard’s requirement for effective sunglasses ensures the wearer’s eyes have adequate protection against UV radiation damage. The standard defines five categories of lenses (Table 2).
Table 2. Categories of lenses in sunglasses and labelling required
|0||Fashion spectacles – not sunglasses. Very low sunglare reduction – some UVR protection||None|
|1||Fashion spectacles – not sunglasses. Limited sunglare reduction – some UVR protection||Not suitable for driving at night|
|2||Sunglasses. Medium sunglare reduction and good UVR protection||None|
|3||Sunglasses. High sunglare reduction and good UVR protection||None|
|4||Special purpose sunglasses. Very high sunglare reduction and good UVR protection||Must not be used when driving|
While too much UV radiation exposure can cause sunburn, premature ageing, and skin damage leading to skin cancer, a healthy balance of UV exposure is important for health. Too little UV exposure may lead to vitamin D deficiency, which can cause significant risk to musculoskeletal health and bone density. Hence, it is important to take a balanced approach to UV in order to maintain adequate vitamin D levels while minimizing the risk of skin cancer with appropriate sun-protection measures.
In 2004, Australia was the first country in the world to develop a joint position statement on vitamin D and the risks and benefits of UV exposure. As the evidence accumulated, a revised version of the position statement was made public in 2007.26 The statement was a point of reference for each agency to guide their public health messaging. Regular sunscreen use does not appear to be linked to vitamin D deficiency.27,28
SunSmart in schools
SunSmart recommends that all schools have a SunSmart policy to ensure a healthy UV exposure balance – one that minimizes skin cancer risk and helps with vitamin D. This also helps address duty of care and health and safety responsibilities for staff and students. SunSmart has a number of resources, sample policies, family notes and online curriculum support to help share the SunSmart message.
SunSmart recommends that school uniform/dress code policies include the following minimum standards. (1) Clothing to cover as much of the students’ skin as practicable: (i) a shirt with at least elbow-length sleeves (although three-quarter length sleeves provide better protection from the sun); (ii) a collar that sits close to the neck, above the collarbone (scoop necks, V-necks or any other necklines below the collarbone are not recommended); (iii) longer style skirts/shorts/trousers at least to the knee (although three-quarter length shorts/trousers provide better protection from the sun). (2) A sun-protective hat to be worn outdoors from September to April: (i) broad-brimmed hats with a minimum brim width of 7·5 cm; (ii) bucket or ‘surfie-style’ hats with a deep crown and brim of at least 6 cm; (iii) Legionnaire hats with a flap that covers the neck (the side flap and front peak should meet to protect the side of the face); (iv) baseball caps are not recommended.
Sports and outdoor events
Many popular sports such as cricket, tennis, golf, lawn bowls, athletics, surfing and triathlon experience their highest participation between September and April when UV radiation levels reach high to extreme levels in Victoria. Protecting oneself with the five sun-protection steps is particularly important, especially when individuals are spending hours outside in the sun.
A sun-protection policy at sports club can protect members, employees, volunteers and spectators. SunSmart recommends the following. (i) Promoting and using the SunSmart UV Alert by adding the widget on to the club’s website. (ii) Scheduling training times, competitions and outdoor events outside the UV Alert times when possible (especially those scheduled for the middle of the day). (iii) Planning and providing shade – encouragement of players and spectators to take advantage of natural shade from buildings and trees. (iv) The addition of portable shading or consideration to building permanent shade in popular outdoor spots. (v) Encouraging people to bring their own portable shade to club events. (vi) Encouraging club ‘sports stars’, coaches and club officials to be sun-protection role models. (vii) Providing or encouraging participants and officials to wear sun-protective clothing as part of the team uniform and during training sessions. (viii) Promoting the use of SPF 30+ broad-spectrum, water-resistant sunscreen. Clubs may even consider having a supply on site. (ix) Encouraging spectators to come to events prepared for the outdoors by reminding them to be SunSmart. Promotion of sun protection during the day with signage, announcements and providing sunscreen for unprepared spectators. (x) Educating club members and coaches about skin cancer and sun protection, e.g. placement of articles in club newsletters, poster display and use of a blackboard to display the UV Alert for the day.
UV radiation is a proven human carcinogen.29 Ten minutes in a sunbed matches the cancer-causing effects of 10 min in the Mediterranean summer sun.30 However, Australian sunbeds may emit at a UV index of 36+, so there would therefore be substantially greater effect. A systematic review of the literature until March 2009 on epidemiological and biological studies on sunbed use showed that use of sunbeds was positively associated with CMM. First exposure to sunbeds before age 35 years significantly increased the risk of melanoma.31 The Fashion to Die For campaign was developed by Cancer Council Victoria to highlight the dangers of using solariums. The campaign targeted 18- to 30-year-old women, who are the biggest users of solariums. It told of personal stories from girls who have used solariums and outlined the myths and facts about sunbeds. This campaign and the death of an antisunbed campaigner, Claire Oliver, has raised considerable public and political awareness of the dangers of sunbed use.32
From 1 February 2009, the Radiation Amendment (Tanning Units and Fees) Regulations were implemented in Victoria, and other states have since followed suit. Sunbed operators must have a licence to operate and the licence requires that operators must: (i) ban people under 18 years of age from using their solarium; (ii) see evidence of age documents for clients who may be under 18 years; (iii) ban people with very fair skin (skin phototype I) from using their solarium; (iv) display mandatory health warnings; (v) provide a consent form outlining the risks of solarium use for customers to read and sign; (vi) complete a skin assessment of all clients; (vii) ensure all staff have completed training in carrying out skin assessments and determining exposure times; and (viii) ensure clients wear protective eyewear.
The Victorian Government has publicly stated that the number of solarium establishments have declined by over 65% since the legislation was implemented.33
Reducing exposure to UV radiation, both solar and artificial, contributes to the reduction of the incidence of skin cancer. This is achieved by using a combination of sun-protection measures. Many risk factors are associated with the development of skin cancer and a holistic approach to prevention and early detection is required. Such approaches need to consider cultural, socioeconomic, environmental, political and legislative impacts.
What’s already known about this topic?
- • Reduction of skin exposure to ultraviolet radiation has been recommended by the World Health Organization to reduce skin cancer rates.
- • Australia has among the highest incidence and mortality rates for skin cancer in the world.
What does this study add?
- • A description of the Australian SunSmart programme, which tries to influence the knowledge, attitudes and intentions of individuals, along with social and cultural norms in an attempt to promote sun-protection behaviour.