Last partial update: July 2019 - Please read disclaimer before proceeding
Skin cancer incidence
Australia unfortunately has the highest rate of skin cancer in the world. Approximately 66% of people living in Australia will develop skin cancers, with about 1,200 dying of these cancers each year. It is an unfortunate fact that almost all of these cancer deaths and many of the cancers themselves are preventable.
Almost all skin cancers are the direct result of long-term exposure to ultra-violet radiation (UVR) from the sun. Sun beds and solariums also result in exposure to harmful UVR.
Melanoma causes most of the burden of disease asociated with skin cancer; about 82%. In males it is the fifth largest cause of illness due to cancer, causing 5.0% of all illness due to cancer; and in females it is the eighth largest cause of illness, causing 3.1% of all illness due to cancer (2011).
Types of skin cancer
Melanomas
Melanomas are pigmented skin cancers that form from cells that produce the pigment in the skin. They are less common than the other main types of skin cancer but are much more dangerous as they can cause death by spreading throughout the body; a process termed metastasising. They are responsible for most of Australia’s skin cancer deaths. Australia has the highest rate of melanoma in the world, with the incidence rate and death rate being considerably higher for males. About 8,000 people develop melanomas in Australia each year. They are rare before puberty and the incidence gradually increases until plateauing at the age of 50 years.
Pigmented skin lesions (naevi) are the precursor (starting) lesions for these melanomas. Almost all of these lesions are acquired due to sun exposure, with fewer than two per cent of the population being born with pigmented lesions. Pigmented lesions tend to develop in the first 40 years of life, with few appearing after this time. Thus, while most of the burden of disease from melanomas occurs from middle age onwards (see figure below), preventing melanomas relies on minimizing exposure to damaging UVR in childhood and early adult life. Child sun protection is paramount in preventing melanomas, with avoiding episodes of sunburn being especially important!!
Melanomas can develop either as a new pigmented lesion or a change in an existing pigmanted lesion. Existing pigmented lesions that are irregular in outline and uneven in colour (called dysplastic naevi) are the lesions most likely to become melanomas. Some people have many of these naevi and excluding / treating melanomas in these people is a difficult lifelong process. (It is worth mentioning that 50 per cent of the melanomas that develop in high risk people with multiple dysplastic naevi occur spontaneously in normal looking skin, not these abnormal lesions.)
Melanoma appearance: Melanomas can vary greatly in appearance. Commonly they have an irregular edge and they can be flat or raised. Their colour is usually uneven and may be any combination of black, brown, blue, red, white and light grey; and about 10 per cent are not pigmented at all. They may bleed or itch. Any new or changed pigmented lesion in an adult should be examined by a doctor without delay to exclude a possible melanoma.
Melanoma risk factors: Risk factors for the development of melanoma include having fair skin that tans poorly, a tendency to freckle easily, high sun exposure (especially if this occurred as a child), the presence of over 100 pigmented lesions on the body, and the presence of atypical or unusual pigmented lesions. People with a depressed immune system are also at greater risk. There is also a slightly increased risk if a first degree family member has had a melanoma.
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Other important skin cancers – BCCs and SCCs
The two other main types of skin cancers are squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). Both these cancers are also due to sun exposure. However, unlike melanomas, they usually do not spread to other parts of the body and are thus less dangerous. The main exception to this rule is SCCs occurring on the face (especially on the lips) which can spread and which can occasionally cause death. Also, BCCs can cause considerable disfiguring local damage if not treated early; especially when they occur on the face.
Common precursor lesions for SCC are the solar keratoses that are regularly burnt or frozen off the skin of almost all adult Australians from middle age onwards.
Preventing skin cancers
Almost all skin cancers are caused by the sun’s ultra-violet radiation (UVR), which causes skin cancer cells to be formed through mutations to skin cell genes. UVR also weakens the skin’s immune system and in doing so reduces the body's ability to fight skin cancer when it occurs.
As well as causing skin cancer, UVR also damages the deeper parts of the skin called the connective tissues. This damage is responsible for the early ageing (e.g. wrinkling) that occurs in sun-damaged skin. There are two types of ultra-violet radiation, UVA and UVB, and exposure to both types should be reduced. This is important when choosing a sunscreen.
In Australia, avoiding UVR means a life long ritual of reducing time spent in the sun, wearing adequate protective clothing, and the use of sun screens. These protective measures will now be discussed in more detail.
Fortunately, there are early signs that improved sun protection is having an effect, with evidence from some states showing that the incidence of melanoma is starting to fall in younger adults.
a. Reducing time spent exposed to UVR.
Most Australians experience excessive exposure to sunlight that causes skin damage and It is important to minimise sun exposure whenever possible; especially during the middle of the day (from 11am until 3pm during daylight saving and from 10am until 2pm during other times of the year). UVR levels can be quite high even on cloudy days and it is important to keep in the shade whenever possible. When heading outdoors, take shade with you in the form of hats, umbrellas etc and try to provide as many shady areas around the home as possible, especially near/over pools and children’s play areas.
While UVR is less in winter it is still present and is especially a problem in the snow country, where up to 88 per cent of UVR is reflected onto the face. At higher altitudes there is also significantly more UVR present. For example, at an altitude of 2000m the UVR level is about 30 per cent higher than it is at sea level.
Occasional intermittent exposure to excess sunlight that results in sunburn should also be avoided, especially in people who are not normally exposed to excess sunlight, as it has been shown to also increase the risk of developing melanomas. (For example, melanomas have occurred in Icelanders who holiday lying in the sun in the Mediterranean)
b. Wearing appropriate protective clothing.
A good hat that has a tight weave and a broad brim (8 to 10 cm for adults and 6 cm for children) is a very important part of sun protection. When wearing a hard hat at work or while bike riding, a brim and neck flap should be attached. Baseball type caps are not as good a choice as they do not protect your ears, your neck, and much of your face, all of which are common sites for skin cancers. No matter what type of hat is choosen, sunscreens are still needed for the head and neck to protect against UVR reflected from the ground.
Clothes should cover limbs and neck (i.e. have collars) and be made of a fabric that has a fairly close weave. (Cotton is a good protective fabric.) Try to avoid sleeveless tops with no collars. Rash vests offer good protection for both adults and children when in the water. Long sleeves are best and remember that their UVR protection does decrease as the garment ages. A good way of assessing how ‘sunlight-protective’ an article of clothing is is to see how much of a shadow it creates when held in sunlight.
c. Apply a good sunscreen and do it properly
When about to be exposed to UVR, it is important to apply a broad spectrum SPF 30+ sunscreen which protects against UVB and UVA and gives immunoprotection from sunlight. An eight-minute exposure to sunlight can reduce the skin’s immune protection by up to 35 per cent. The sunscreen should also be water resistant if the person is likely to swim or sweat a lot.
How to apply sunscreen
Before using a new sunscreen, try a small test patch on an arm overnight to identify any allergy or irritation. As a general rule, creams and lotions are less likely to cause skin problems than alcohol-based products.
When: Sunscreens need to be applied 20 minutes before sun exposure. This is because 'rubbing in' the cream breaks down the sunscreen’s ‘water-in-oil emulsion’ barrier to UV light. This takes about 20 minutes to reform on the skin. The cream should be applied evenly to the skin.
How much: For an adult, one teaspoonfull (5mLs) for EACH limb, the face (including neck and ears), your back and your chest / abdomen. This means 35mLs (7 teaspoons) for the whole body. This means a 110mL tube on sunscreen will do three full body applications. Wearing high sun protection factor rash vests will the amount needed.
How often: Sunscreen needs to be applied every 2 hours or after swimming, sweating or drying yourself with a towel
Cancer council advice re sunscreens
It is important to understand that sunscreens cannot filter out all UVR. A SPF30+ preparation applied properly can be expected to cut out 97% of UVR. Thus if a person were going to get sun burnt in ten minutes with no sunscreen, he or she will still get sun burnt in about 300 minutes with properly applied SPF30+ cream; and a lot sooner if it is not properly applied initially or not reapplied regularly. SPF15+ sunscreens give only half the protection of SPF30+ sunscreens and should be avoided unless a SPF30+ product is not available. Sunscreens do deteriorate with age and it is important to check the expiry date of the cream regularly and replacecream that is out of date.
Do sunscreens help prevent skin cancers? YES!!
Sunscreens have been proven to prevent longer-term skin damage and reduce the development of pigmented lesions. These are known causes of melanomas and other skin cancers and it is therefore extremely likely that long-term regular sunscreen use will greatly reduce the future incidence of skin cancers in Australia. At present there are numerous studies being conducted to confirm the ability of sunscreens to stop skin cancers developing. To date, these studies have shown that adults who apply sunscreens regularly do have a reduced incidence of SCCs.
While melanomas and BCCs both appear maximally from middle age onwards, both are likely to be initiated by sun exposure much earlier in life. For this reason, it is necessary to study the use of sunscreens in children and younger adults to prove that sunscreens do in fact reduce the incidence of these cancers in older people. As such studies obviously take a long time to complete, there have to date been no studies completed to confirm protection against melanomas and BCCs. However, early results have been encouraging and, as sun screens have been shown to stop solar UVR from causing the skin damage and pigmented skin lesions that cause these cancers, is extremely likely they will to be shown to prevent melanomas and BBCs.
It is important to emphasise once again that preventing melanomas requires the protection of children’s skin.
What’s in sunscreens?
Active ingredients: These may act by either absorbing or reflecting UVR
- UVA & UVB protective - titanium dioxide, oxybenzone, zinc oxide
- UVA protective only - Homosalate, butyl methoxydibenzoylmethane
- UVB protective only - octyl methoxycinnamate, octyl salicylate, padimate O, octocrylene.
Stabilizers: These act to stop the active ingredients being broken down by UV light.
Preservatives
PerfumesDo sunscreens help prevent skin cancers? YES!!
Sunscreens have been proven to prevent longer-term skin damage and reduce the development of pigmented lesions. These are known causes of melanomas and other skin cancers and it is therefore extremely likely that long-term regular sunscreen use will greatly reduce the future incidence of skin cancers in Australia. At present there are numerous studies being conducted to confirm the ability of sunscreens to stop skin cancers developing. To date, these studies have shown that adults who apply sunscreens regularly do have a reduced incidence of SCCs.
While melanomas and BCCs both appear maximally from middle age onwards, both are likely to be initiated by sun exposure much earlier in life. For this reason, it is necessary to study the use of sunscreens in children and younger adults to prove that sunscreens do in fact reduce the incidence of these cancers in older people. As such studies obviously take a long time to complete, there have to date been no studies completed to confirm protection against melanomas and BCCs. However, early results have been encouraging and, as sun screens have been shown to stop solar UVR from causing the skin damage and pigmented skin lesions that cause these cancers, is extremely likely they will to be shown to prevent melanomas and BBCs.
It is important to emphasise once again that preventing melanomas requires the protection of children’s skin.
d. Providing adequate shade around your home / garden
It is important to consider providing adequate shade when designing your home and garden. Design needs to take into consideration variation in sun angle that occurs both during the day and over the year and consideration should be given to the provision of side-on protection to reduce exposure to scattered light. Positioning should take into account where most activity is likely to be both adjacent to the house e.g. where people are likely to eat outdoors and be in the garden.
e. Avoid ultraviolet radiation (UVR) exposure associated with solarium use
The use of sun beds and solariums causes exposure to UVR, which results in skin damage and adds to the risk of developing skin cancers. Do not believe any reassurances given. They are not safe.
Screening for melanomas (and other skin cancers) – Early detection is crucial in preventing death from melanomas
Finding and treating melanomas early ensures a cure for the vast majority of these potentially lethal lesions. For this reason, all people at increased risk of melanoma should be screened at least annually from their early teenage years. This involves looking at all skin areas as melanomas can occur anywhere, including unusual places such as under nails, on the soles of feet, and even inside the eye. People at increased risk of melanomas should also regularly (monthly) examine themselves for new skin lesions or changes in existing skin lesions and have any new or changed lesion reviewed promptly by their GP. (Areas such as the back and head need to be examined by another family member or friend.)
Those at increased risk of developing melanoma include people with the following.
- Multiple pigmented lesions
- A previous history of melanoma or lesions that are more likely to turn into melanomas. (These are called dysplastic naevi and are pigmented lesions that are irregular in shape and uneven in colour.)
- A family history of melanoma or pre-melanoma lesions (dysplastic naevi) in a primary relative (parents or siblings) (The presence of such a family history increases melanoma risk by up to five times normal.)
- Freckles
- A tendency to sunburn easily rather than tan.
- A past history of non-melanoma skin cancer
- Light / red hair colour
- High levels of sun exposure, especially if this occurred as a child. (Significant episodes of sunburn in childhood are thought to be a causal factor and should be especially avoided.)
In addition, as part of a routine medicals, all people should be checked regularly (preferably each year) for all skin cancers.
Any skin lesion that a person is concerned about should be seen immediately by his or her GP and not left to increase in size. (Do not wait till your next routine visit.) This especially applies to pigmented lesions and any lesions on the face or ears as these can be much more difficult to treat. Dysplastic lesions (see above) need especially careful observation. The signs to be concerned about include any new lesion, spots etc that change size, shape or colour, sores that don’t heal, and anything else that causes concern. Remember that many melanomas (about 20 per cent) do not present typically and 10 per cent are not pigmented (coloured) at all. Thus, there needs to be a high index of suspicion of lesions that have recently appeared, enlarged or otherwise changed, especially if it is associated with a persistent itch. See a doctor when worried!!
Removing a suspicious pigmented lesionSuspicious lesions need to be totally removed; called an excision biopsy. To ensure total removal, the removed specimen needs to include at least a 2mm margin of normal skin around the edges of the pigmented lesion and a layer of subcutaneous fat beneath it. Lesions can often be removed by GPs, although large lesions that are difficult to completely remove and lesions where the cosmetic result is an important issue (such as lesions on the face) should be referred to a surgeon. Any biopsy that involves removing only part of the lesion is not recommended as it does not give an idea of the depth of the total lesion, which is needed for planning treatment. Punch biopsies or doing a shave biopsy are examples of such inappropriate biopsies. |
UV light & sunglasses / glasses
Numerous eye problems are related to sun (UVR) damage. These include the following.
- BCCs and SCCs on the skin around the eye. These are often difficult to remove as there is little excess skin available and delicate structures are often involved, such as eyelids. SCCs can also occur on the conjunctiva (white part of the eye). These lesions are best emoved by a specialist surgeon.
- Melanomas on the skin surrounding the eye, on the conjunctiva, on the iris (the coloured part of the eye) and in the eye itself. About 180 eye melanomas occur in Australia each year.
- Pterygiums, which are non-cancerous growths that occur across the cornea. (The cornea is the translucent circular-shaped structure covering the central part of the eye.)
- Cataract (An opacity occurring in the lens of an eye). These are mostly caused by chronic exposure to UVB radiation and occur mostly in later life. People who work outside are much more likely to develop cataracts and wearing sunglasses from a young age can reduce risk significantly.
To give adequate protection, sunglasses should fit close to the face and wrap around the eyes. They should also meet with the Australian Standard 1067.2 specifications for sunglasses, which should be shown on the tag attached to the glasses. Such glasses protect against 99 per cent of UVR. Neither the colour of the glass nor the cost of the glasses influences the degree of protection given.
Modern prescription glasses have adequate filters for UV light already built in and tinting is not needed.