Exposure to ultraviolet rays of the sun is the single most important cause of melanoma, which is the most serious form of skin cancer in terms of mortality.
There is a strong link between episodes of sunburn in childhood and the subsequent development of melanoma due the accumulation of the effects of damage to the skin.
The cancer-inducing damage to the DNA in the skin cells sustained with each episode of sunburn is irreversible. As a result, this cumulative damage tends to translate into skin cancer decades later.
Melanoma may develop anywhere on the skin, and within a pre-existing mole in 30 to 50 per cent of cases. It normally appears as a brown/black patch or lump with irregular features. The ABCDE criteria provide a useful guide for diagnosing melanoma:
Asymmetry. Melanoma is asymmetrical, i.e., it cannot be divided into two equal halves;
Border. Melanoma has an irregular indented border as opposed to a smooth rounded border;
Colour. Melanoma consists of more than one shade as opposed to one uniform colour;
Diameter. Melanoma is usually larger than 6mm in diameter. This last criterion is only valid in the presence of an abnormal shape and colour;
Evolution. Recent change in size, shape and colour, spontaneous bleeding, and irritation.
Besides melanoma, the sun causes other forms of skin cancer which, even though are not usually fatal, often produce significant disfigurement.
The sun’s ultraviolet rays also cause premature ageing of the skin in the form of wrinkles, blemishes, roughness, broken veins and scaly patches.
The risk of developing melanoma is higher in somebody with fair skin which burns and freckles easily, and in those with numerous moles.
The risk is higher in somebody with fair skin which burns and freckles easily, and in those with numerous moles
A history of sunburn, especially in childhood and adolescence, and of melanoma in another family member also contribute to a higher risk of melanoma.
Melanoma can occur at any age. However, it is rare in childhood. Many factors are leading the increase in melanoma cases over time.
The atmosphere’s ozone layer restricts the transmission of type B and C ultraviolet light. Since the 1980s, a sustained depletion of stratospheric ozone levels has been occurring, especially in middle latitudes (-30 to -60). Along with this depletion, the amount of ultraviolet light that reaches the earth surface is increasing. In addition, people’s behaviour in the sun has been the main cause for the rise in skin cancer rates in recent decades.
Over time, people are opting for more outdoor activities and sunbathing, leading to excessive UV exposure. Many people consider sunbathing as a pastime, lounging near the beach or pools, and some even perceive a suntan as a symbol of beauty and good health. However, the reality is that a suntan is merely a sign of UV damage and represents the skin’s reaction to minimise further harm.
Melanoma skin cancer invades the skin and can spread to other organs in the body, often with fatal consequences. The key to a favourable outcome is early detection and timely surgical treatment. Surgical removal of a melanoma caught in an early stage can lead to a very good survival rate of 90 to 95 per cent at five years. If melanoma spreads, the chances are not so good. Periodic self-examination of the skin and early referral to medical attention is important.
Some tips for prevention include:
▪ Limit time in the midday sun
The sun’s UV rays are strongest between 10am and 4pm. Limit exposure to the sun during these hours. Sun protection is not only necessary on the beach or by the swimming pool but applies to all outdoor settings.
Children can be exposed to sunlight on the balcony at home, during school breaks and during outdoor sporting activities.
Transmission of the sun’s rays through car windows is also significant. Particular attention should also be given by people who have a predominantly outdoor occupation.
▪ Watch out for the UV index
This important resource helps you plan your outdoor activities in ways that prevent overexposure to the sun’s rays. While you should always take precautions against overexposure, take special care to adopt sun safety practices when the UV index predicts exposurelevels of moderate or above.
The UV index is nowadays an integral part of the local weather forecast. It is an indicator of the intensity of harmful UV rays around midday. The index ranges from zero to 11+ and is an excellent guide to the recommended level of sun protection on a day-to-day basis.
▪ Use shade wisely
Seek shade when UV rays are the most intense, but keep in mind that shade structures such as trees, umbrellas or canopies do not offer complete sun protection. Remember the shadow rule: Watch your shadow: short shadow, seek shade.
▪ Wear protective clothing
A hat with a wide brim offers good sun protection for your eyes, ears, face and the back or your neck. Sunglasses that provide 99 to 100 per cent UV-A and UV-B protection will greatly reduce eye damage from sun exposure. Tightly woven, loose fitting clothes will provide additional protection from the sun. There now exist on the market clothing, including swimwear, with inbuilt sun protection (up to factor 50) for children.
▪ Use sunscreen
Apply a broad-spectrum sunscreen of SPF 30+ liberally and re-apply every two hours, or after working, swimming, playing or exercising outdoors. A total ‘sunblock’ does not yet exist and some wavelength UV rays do not get filtered, so one should not overstay in the sun.
▪ Avoid sunlamps and tanning parlours
Sunbeds damage the skin and unprotected eyes, and are best avoided.
With proper prevention measures and early diagnosis, we can decrease the impact of melanoma on health.
A future look of non-UV-damaged skin needs to become the new health and beauty standard.
| UV index | Category | Recommended sun protection |
| 0-2 | Minimal | Wear a hat |
| 3-4 | Low | Wear a hat and sunscreen |
| 5-6 | Moderate | Wear a hat, sunscreen, stay in shade 11am-4pm |
| 7-9 | High | As above and, preferably, stay indoors 11am-4pm |
| 10-11+ | Very High | As above and greater effort to stay indoors 11am-4pm |
Prof. Charmaine Gauci is Superintendent of Public Health.