Sunshine. Without it, our little blue planet would be a shivering dry rock. The sun gives off electro magnetic radiation, including visible light (sunlight), infrared energy (heat), ultraviolet (UV) radiation, and radio waves. While most forms of radiation are filtered out by the atmosphere, UVA radiation is hardly affected, with most reaching the ground. Ultraviolet radiation is strongest when the sun shines brightest (closer to the equator, during summer months, and during the midday hours between 10am and 3pm), in higher altitudes, and where surfaces such as snow, water, sand and pavement reflect light and ultraviolet radiation.
Contrary to popular opinion, a cloudy sky does not offer full protection and under light cloud the level of UV can be almost as high is in direct sunlight. And UV radiation is completely unrelated to the temperature – a sunny, but cool day can still register considerable levels of ultraviolet radiation especially around midday.
THE TRUTH ABOUT TANS
UV radiation can cause premature ageing and damage at a cellular and molecular level.
It can also stimulate the cells to produce a thicker epidermis (‘leathery’ skin) and can cause premature skin ageing.
As a defence against ultraviolet radiation, our skin produces a pigment called melanin, aka a suntan. Over the years tanned skin has been perceived as fashionable, evocative of luxury and health. But what does UV radiation have to do with a suntan?
UV radiation stimulates the production of melanin, but it can also cause direct damage to our cellular DNA as the process usually results in some degree of sunburn. Sunburned skin doesn’t just look and feel awful; repeated sunburns can cause permanent damage over time and is known to increase the likelihood of developing skin cancer.
On the upside, melanin’s properties make it a photoprotectant as it can absorb UV radiation and dissipate the energy as heat. But depending on the skin type, the average sunburn protection offered by a suntan is only SPF4.
According to the Australian Department of Health and Ageing, Australia has the highest skin cancer incidence rate in the world, with Australians being four times more likely to develop skin cancer than any other form of cancer. A frightening two out of three Australians will be diagnosed with skin cancer before the age of 70 and, in 2011, there were 1544 deaths from melanoma and 543 reported deaths from non-melanoma skin cancers.
The Cancer Society of New Zealand reports equally distressing statistics, with skin cancer being by far the most common cancer affecting New Zealanders.
The adage ‘prevention is better than cure’ has never rung more true than for skin cancer. Even if you do live in a cave, exposure to sunlight is inevitable, but there are ways to protect your skin and reduce the risks. The cumulative nature of sun damage to skin (the skin ‘remembers’ each burn) means ideally that our skin should be protected from over-exposure from the day we’re born.
As with any form of protection, sunscreen can only do its job if it’s applied correctly.
The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) says the internationally-accepted application thickness of sunscreen is 2mg per square centimetre, which is about 30ml (six teaspoons) of sunscreen lotion for an average male adult’s body. So a 120ml tube of sunscreen should only last four applications.
Sunscreen should be applied liberally to dry, clean skin 30 minutes before going outside. Re-apply every two hours or more frequently if you’ve been sweating, have gone for a swim, or rubbed off with a towel – even if using water-resistant sunscreen.
The Sun Protection Factor (SPF) of a sunscreen is, not surprisingly, a measure of how well it can protect skin from sunburn.
The TGA (Australian Department of Health – Therapeutic Goods Administration) gives this example: if skin covered with liberally applied sunscreen takes 300 minutes to burn during the laboratory test, but only 10 minutes to burn without sunscreen, the SPF is 300/10, or SPF30.
So, if skin starts to burn after five minutes, times SPF30, that’s 150 minutes. Re-applying sunscreen after your 150 (or however many) minutes are up does not extend the time.
When shopping for sunscreen, look for broad spectrum products with an SPF suited to the amount of time you intend to be in the sun and your skin type. The choice of product is huge and even SPF50+ sunscreens come in ‘dry touch’ varieties so you don’t need to feel like an oily sardine.
Protection Category 2012 Standard
Low SPF 4, 6, 8, 10
Moderate (or medium) SPF 15, 20, 25
High SPF 30, 40, 50
Very high SPF 50+
SPF 50+ isn’t a suit of armour
While sunscreen can do much towards protecting skin from the harmful effects of the sun’s rays, no sunscreen product can provide 100 per cent blockage of UVA and UVB radiation. According to ARPANSA, a broad spectrum sunscreen of SPF15 blocks approximately 93 per cent of the ultraviolet rays, while an SPF30 blocks approximately 96 per cent.
DRESSED TO PROTECT
One of the best barriers between the sun and skin is clothing. Not all fabrics are created equal, however, and while a T-shirt and boardshorts might be the customary summer outfit of choice, it hardly offers the best protection.
Similar to the SPF rating for sunscreens, sun protective fabrics are rated by UPF (Ultraviolet Protection Factor). This table shows the rating system.
UPF rating Protection category % UV radiation blocked
15, 20 Good 93.3–95.9
25, 30, 35 Very good 96–97.4
40, 45, 50, 50+ Excellent 97.5 or more
But before you consider ditching your entire summer wardrobe in favour of garments carrying an ARPANSA-approved UPF label, know that some fabrics found in the average Aussie or Kiwi closet provide a decent level of sun protection, including denim (especially dark blue or black), wool, polyester and shiny polyester blends, plus many other tightly-woven fabrics.
Exposure to ultraviolet radiation can also cause damage to eyes.
All sunglasses and fashion spectacles sold in Australia and New Zealand must be tested and labelled according to the Australia/New Zealand standard AS/NZS1067:2003 Sunglasses and Fashion Spectacles, one of the toughest mandatory sunglass standards in the world. This standard covers lens categories, construction and labelling requirements.
Lens category Description Additional markings
0 Fashion spectacles – not sunglasses very low sunglare reduction – some UV protection None
1 Fashion spectacles – not sunglasses limited sunglare reduction – some UV protection Not suitable for driving at night
2 Sunglasses – medium sunglare reduction and good UV protection None
3 Sunglasses – high sunglare reduction and good UV protection None
4 Special purpose sunglasses – very high sunglare reduction and good UV protection Not to be used for night driving
Sunglasses also come with an Eye Protection Factor (EPF) rating. Much like SPF for sunscreen and UPF for fabrics, EPF has a numerical rating scale (from 1 to 10) to classify how well a lens blocks ultraviolet radiation. Sunglasses with an EPF of 9 or 10 transmit almost no ultraviolet radiation.
Sunglasses typically have a dark tint and the darker the tint, the more they reduce visible light. But it’s not the colouration of the lenses that provide protection – it’s the ultraviolet radiation-absorbing properties of the lenses that do this. This means that dark sunglasses are not necessarily more effective at protecting the eyes from ultra violet radiation than lightly tinted sun glasses… a good incentive to always check the EPF.
The epidermis (the outermost layer of skin) contains three different types of cells: squamous cells, basal cells and melanocytes. Skin cancers are named after the type of cell from which they develop. The three main types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and melanoma.
Basal cell carcinoma
The most common and least dangerous form of skin cancer, basal cell carcinoma (BCC) develops from the cells at the basal (inner) part of the epidermis.
BCCs grow slowly, usually appearing on skin most often exposed to ultraviolet radiation (head, neck, hands, forearms and upper body) as a round or flattened lump or scaly area. They often look like open sores, a red patch or ‘irritated’ area, shiny bumps or nodules, pink or skin-coloured growths, or even scar-like.
If detected early, BCC can be removed quite effectively using various surgical techniques, and usually as an outpatient.
Squamous cell carcinoma
Squamous cell carcinomas (SCC) are less common than BCCs, but grow faster.
SCCs of the skin are most common on areas of the body most exposed to ultraviolet radiation (the head, neck, hands, forearms and upper body). They often appear as a persistent rough, scaly patch that can bleed if bumped, red scaly patches, open sores, elevated growths with a central depression that can look flaky and occasionally bleed, or like warts that may crust or bleed.
If not treated, they carry a significant risk of metastasis, often spreading to the lymph nodes and in some cases to distant tissue and organs, which can become fatal.
Melanomas develop from the melanocytes (pigment cells) in the skin and most commonly occur on parts of the body that have been sunburned. Melanomas can occur anywhere on the skin, even on the soles of the feet or under fingernails.
Melanomas may appear as a new spot or develop from an existing mole. They can begin as a flat spot that changes in size, shape, or colour. A less common type of melanoma (nodular melanoma) is not flat, but is raised from the start. These melanomas are often pink or red, and grow quickly.
If melanomas are not treated, they may spread to the lower layer of skin where cancer cells can escape and be carried to other parts of the body in blood or lymph vessels. If treated in the early stages, most melanomas can be treated successfully. If they are not detected until later, they can become fatal.
Who’s at risk?
Anyone can develop skin cancer, but some are more at risk than others. Those at higher risk of developing skin cancer are those who: • Previously had a skin cancer
• Have a family history of skin cancer
• Have a large number of moles on their skin, especially dysplastic moles (these can be larger than most moles, can have irregular edges, can be uneven in colour, or can have some pinkness)
• Have fair skin or skin that burns easily
• Have a history of severe sunburns
• Spend lots of time outdoors, unprotected, during their lifetime
• Actively tan or use solariums, sunlamps and sunbeds
• Work outdoors.
Where to go for advice
Skin cancer is relatively easy to spot as it’s visible, but early detection is crucial. Most skin cancers can be successfully treated if detected early.
It’s highly advisable to have your skin checked regularly, even if you don’t think you’re at risk.
The first port of call should be a general practitioner, who will examine your skin and check for any suspicious spots. The GP will advise what the most appropriate course of action is and may refer you to a specialist (such as a dermatologist or surgeon) for diagnosis or treatment. Keep in mind that before seeing a specialist, a referral from a GP is needed.
Skin clinics are usually operated by GPs and offer a variety of services and fee arrangements. According to the Cancer Council, research indicates skin cancer clinics may not necessarily offer a higher level of expertise than a GP. Before deciding where to go, it’s advisable to find out about the services offered, the expertise of the person who will examine you, what costs may be involved (especially for follow-up treatments), and what they will do if a suspicious spot is detected.
The Cancer Council Australia (cancer.org.au) has local Cancer Councils in each state/territory and, together with its skin cancer control program SunSmart (sunsmart.com.au), is an excellent source of information. SunSmart’s range of sunscreens, hats, sunglasses and portable sun protection products is available at various health outlets and pharmacies and on its website: cancervic.org.au/store.
The Cancer Society of New Zealand (cancernz. org.nz) also offers a wide range of sunscreens and sun protection products such as hats and sunglasses. They’re available at various health outlet sand pharmacies, or online: cancernz.org.nz/products.
SunSmart recommends: During critical sun protection times (when the UV index is at three or above), use a combination of the five sun protection measures:
1. Slip on sun-protective clothing that covers as much skin as possible
2. Slop on SPF30 or higher sunscreen – make sure it is broad spectrum and water-resistant. Apply 20 minutes before you go outdoors and reapply every two hours
3. Slap on a hat that protects your face, head, neck and ears
4. Seek shade
5. Slide on sunglasses – make sure they meet Australian standards.