Increasing numbers of deaths from malignant melanoma should be prevented by early detection and protection from ultraviolet rays
SummarySkin cancers come in various forms but the type which causes most fear is the malignant melanoma, derived from the pigment-forming cells of the skin or melanocytes.
Skin cancers come in various forms but the type which causes most fear is the malignant melanoma, derived from the pigment-forming cells of the skin or melanocytes. Normal melanocytes are situated near the surface of the skin, at the junction between the outer layer (epidermis) and the deeper layer (dermis). People with naturally fair skin have just as many melanocytes in their skin as darker skinned individuals but they just produce less melanin, which is the brown pigment that the skin needs to protect itself from damage by ultraviolet sun rays. It appears that episodes of sunburn or more persistent exposure to the sun (or radiation from sunbeds) results in changes inside the nucleus of melanocytes which causes them to proliferate more rapidly – the onset of a malignant melanoma. The reason that this type of skin cancer is such a concern is that the cancerous cells can, and do, invade into the skin and eventually can spread by lymphatic or blood vessels into other parts of the body, in some cases leading to death.
Early detection of malignant melanoma should prevent deaths from the disease but, in the last 30 years, the number of men dying from malignant melanoma has doubled, according to the latest figures released by Cancer Research UK. Currently more than 1100 men die from the disease in Britain every year (3.1 per 100,000). The figures reveal a particularly shocking rise in the rate of death from malignant melanoma in men over 65 from 4.5 per 100,000 to 15.2 per 100,000 since the late 1970s. Although more women than men are diagnosed with malignant melanoma, the death rates in women have risen more slowly (from 1.5 per 100,000 to 2.2 per 100,000) in the same period. The rapidly rising number of people developing malignant melanoma is reflected in the numbers diagnosed with the disease early but men are dying unnecessarily because of late diagnosis. Men are either unaware of the symptoms of skin cancer or they are ignoring skin lesions or putting off going to see their doctor. It is crucial that people visit their general practitioner as soon as they notice any new or changing moles. If skin cancer is considered to be a possibility the patient must then be referred urgently to an accredited consultant dermatologist.
The signs of malignant melanoma are described in detail on the website of the British Association of Dermatologists (BAD) but in summary, any new brown or dark spot on the skin, or any mole or growth which is changing in size colour or outline should be a cause for concern. Malignant melanoma can occur anywhere on the body but the most commonly affected sites are the legs in women and the back in men. The following BAD tips for self-checking a mole are given below but skin cancers vary so all skin changes should be reported, even if they are not mentioned here:
- Asymmetry - the two halves of the area may differ in shape
- Border - the edges of the area may be irregular or blurred, and sometimes show notches
- Colour - this may be uneven. Different shades of black, brown and pink may be seen
- Diameter - most melanomas are at least 6mm in diameter. Report any change in size, shape or diameter to your doctor
- Expert - if in doubt, check it out! If your GP is concerned about your skin, make sure you see a Consultant Dermatologist, the most expert person to diagnose a skin cancer. Your GP can refer you.
The rising death toll means it is more important than ever that people are aware of the dangers of too much sun and of sunbeds. The ultraviolet radiation from the sun which reaches the earth, particular UVB radiation, has strong links to malignant melanoma and other types of skin cancer so a sunscreen with a high sun protection factor (SPF) will help prevent the skin from burning and the hope is that it will also prevent the damage that causes skin cancer. UVA radiation can penetrate window glass and penetrates the skin more deeply than UVB and can also lead to skin damage so UVA protection is also needed. Sunscreens can either be absorbers (‘chemical sunscreens’) or reflective materials such as titanium dioxide or zinc oxide. The latter type is more likely to protect against both UVA and UVB radiation but many sunscreens contain a mixture. The SPF rating is a measure of protection against burning (mostly due to UVB) while the UVA star system refers to UVA protection compared with the UVB protection in a product so a low SPF product may have a high level of stars, not because it is providing high UVA protection, but because the ratio between the UVA and UVB protection is about the same. Therefore, for maximum protection a ‘broad spectrum’ sunscreen should provide high SPF and high number of stars. The new EU recommendation classifies sunscreens as shown in this table and the UVA protection for each sunscreen should be at least a third of the labelled SPF. A product that achieves this requirement will be labelled with a UVA logo, the letters “UVA” printed in a circle.
How a sunscreen is applied will affect is effectiveness but in general it is better to apply too much than too little. Some concerns have been raised about the possibility of causing vitamin D deficiency if sun avoidance advice is followed but the dangers of skin cancer are thought to be more important in fair-skinned individuals. There is more information on skin cancer and sun awareness on the BAD website.
Cancer Research UK
Men's skin cancer death rates double in last 30 years
Study supports link between sunbeds and melanoma skin cancer
British Association of Dermatologists
Information on malignant melanoma