The best way to prevent skin cancer is to protect your skin from the sun. Fair skinned/Anglo-Celtic individuals need to develop a lifestyle and/or strategies that minimise their total exposure to sunlight, especially during childhood and adolescence. The single most important issue to understand about protecting the skin from sun damage is that sunscreen lotions themselves should only be considered after the basic measures have been taken:

• Avoid exposure during the midday period (11am-3pm)

• Remember that reflection of UV radiation off surfaces like concrete, sand and water causes you to burn, even if you think you are protected. Use sun shelters or shade whenever possible (eg trees, umbrella, buildings), and choose shade carefully.

• Wear wide brimmed hats and protective shirts which cover the back of the neck. Choose clothing with closely woven fabric.

• Protect your eyes with sunglasses that meet Australian Standard AS1067.

Risk Factors for the Development of Melanoma

While UV exposure has been proven to increase the risk of melanoma there are other factors which can also greatly increase an indviduals chance of being diagnosed with melanoma. Risk factors contributing to melanoma are measured by their Relative Risk (usually referred to as RR).  A higher RR means a greater chance of developing melanoma. For example a history of non-melanoma skin cancer has a RR of 4 for melanoma. This means that if you have such a history, your chance of developing melanoma is 4 times greater than those who do not have a history of non-melanoma skin cancer. Relative Risk factors for melanoma include:

• Total number of naevi (moles).  This is the most important common independent risk factor. The RR for people with 25 to 50 naevi on their body is 4.4 while the RR for 100 or more naevi on the body is 9.8.

• Presence of atypical (dysplastic, or DN) naevi. In patients with DN syndrome the RR is very high. This becomes even higher when there is also a personal or family history of melanoma. The RR for people with 1 to 5 DN is 3.8 while the RR for people with DN syndrome is 17 to 47.

• Caucasian (Anglo-Celtic) races have a significantly increased risk compared with substantial low risk in Asian and dark-skinned races.

• A history of solar keratoses and non-melanoma skin cancer. The estimated RR for non-melanoma skin cancer is 4.

• Pale skin with poor tanning ability has an RR of 3.

• Early onset of living in an area of high ambient solar radiation. A low solar radiation environment prior to 10 years of age has an RR of 0.3.

• Having at least one first degree relative with  melanoma. Only about 5% of melanomas occur in a true melanoma family-prone setting. About 20% of these families have mutations in the p16/CDKN2A gene. The RR of melanoma is 2.2 for individuals who have a family history of melanoma.

• History of sunburn at any age has a RR of 1.9.

• Non-occupational "intermittent" sun exposure has a RR of 1.7.

• Freckling skin has an RR of 1.5.

• Personal history of melanoma increases the risk of a second melanoma.  Australian figures estimate a 12% chance of developing a second melanoma within 10 years of the first diagnosed.

• Increasing age. Melanoma is rare prior to puberty and increases in incidence with age.

• Large congenital naevi (> 20cm or 5% of total body area): RR = 101, even in cohorts where more than half of patients' lesions are partly or completely excised.

Sun Screens

Ultraviolet radiation from the sun is generally grouped into bands A and B. Both contribute to the development of skin cancer and protection from both is needed. UVB is filtered by a number of protective chemical lotions, many of which are easy to apply and essentially invisible. It is important to note however that UVB filters alone do not provide complete protection.

Maximum sunscreen protection is offered by combination/broad spectrum products which combine the UVB chemical filters with micronized titanium dioxide. The titanium cannot be rubbed into the skin so it remains on the surface. These preparations are invariably thicker, a little more difficult to apply, and leave a slightly opaque (usually faint white) layer on the skin surface. These combination/broad spectrum sun screens offer the best protection and are preferred.

Applying sunscreen lotions

Use a sunscreen with sun protection factor (SPF) of 30+, and which is also broad spectrum and water resistant, no matter what type of skin you have. Apply sunscreen 20 minutes before going out and reapply every 2 hours, after swimming or any activity that causes you to sweat.

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