Preventing skin cancer through sun protection advice
A new survey by the Institute of Cancer Research’s SAFE (Skin Awareness for Everyone) campaign has revealed that people are still not following sun safety advice (ICR, 2007).
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The survey of more than 2,000 people found that 60% are more worried about skin cancer now than they were 10 years ago but, despite widespread concern, over one-third (35%) of people do not use sunscreen when sunbathing.
Over 80% of respondents thought that more should be done to educate people about the dangers of skin cancer, as only just over half (52%) know the signs and symptoms of the disease.
However, warnings on the dangers of sunbeds appear to be working, with 82% saying they do not use them.
PREVALENCE OF SKIN CANCER
According to the Institute of Cancer Research more than 75,000 new cases of skin cancer are diagnosed in the UK each year, with around 2,000 deaths. Over the past few decades the incidence of skin cancer has increased dramatically. It has been predicted that the incidence of melanoma skin cancer will treble in the next 30 years, with climate change likely to exacerbate the problem (ICR, 2007).
There are two types of the disease - melanoma (often called malignant melanoma) and non-melanoma (see Box, p22).
Non-melanoma is the most common form of skin cancer, affecting 67,000 people a year in the UK, and can usually be treated with surgery.
Melanoma is the more serious form, affecting 8,000 people in the UK every year. If not caught and treated early, the cancer can spread to other parts of the body and become fatal. The only known environmental risk factor for skin cancer is exposure to ultraviolet (UV) light.
It is known that exposure to UV rays causes damage to cells in the outer layers of the skin. These cells are responsible for producing melanin, the pigment that gives skin colour and protects its deeper layers. Too much exposure to UV rays burns the skin and can cause genetic damage in cells, which can then become cancerous, resulting in melanoma.
Scientists at the Institute of Cancer Research, together with colleagues from the Wellcome Trust Sanger Institute, made the discovery in 2002 that the B-RAF gene is mutated in 70% of melanomas. Now that it is known that mutated B-RAF is a major cause of melanoma, scientists at the institute are working on an intensive programme of targeted drug development.
Prevention and detection
Cancer Research UK’s CancerHelp UK website has a wealth of information on new developments in skin cancer prevention, detection and treatment such as biological therapies (CancerHelp UK, 2007).
CancerHelp UK states that some people are at greater risk of developing melanoma than others, because they have inherited a high-risk faulty gene. Researchers recently discovered one of these genes, called the p16 gene or CDKN2A. A long-term study to find out more about how a person’s genes and their surroundings can affect the risk of developing melanoma is being carried out.
Biological therapy is treatment with substances that originate within the body. Immunotherapy is a type of biological therapy that works by encouraging the body’s immune system to attack cancer cells. Biological therapies being researched for melanoma include:
- Tumour necrosis factor;
- Gene therapy.
Early-stage melanoma is usually treated with surgery. However, for some people there is a risk that the melanoma will recur after surgery, and researchers are investigating whether immunotherapy treatments may help to prevent this.
Interferon is one type of immunotherapy used to treat melanoma. This is made as part of the body’s immune response but it can be manufactured in the laboratory and used in much larger quantities as treatment for cancer and other diseases. A trial on stage 3 melanoma is taking place, which aims to discover whether treatment with interferon lowers the risk of melanoma recurrence after surgery. Interferon has been tried for melanomas that have spread to other parts of the body but has not been shown to be of much benefit so far.
Tumour necrosis factor is an immunotherapy that has been tested, along with chemotherapy, in regional limb perfusion. Regional limb perfusion is a method of giving drug treatment to just one arm or leg that is affected by melanoma. It is usually used for melanoma that has recurred in the same limb. This type of treatment is ‘very experimental’, according to CancerHelp UK.
Cancer vaccines are a fairly new area of research. They have shown some promise as a potential treatment for melanoma, as they may help the immune system to kill the cancer cells. The phase 3 trials that have been carried out have had ‘disappointing results’, CancerHelp UK reports, but research is continuing.
Gene therapy is one of the newer approaches to cancer treatment and is in the very early stages of clinical trials in the UK and US. By studying how changes in these genes cause normal cells in the skin to become cancerous, researchers aim to eventually develop gene therapy so that damaged genes in the cancer cells can be replaced with normal ones.
For information on biological therapies, monoclonal antibodies, chemotherapy and other drugs, see www.cancerhelp.org.uk.
ADVICE TO PATIENTS
People who have fair skin, lots of moles or freckles or a family history are most at risk of skin cancer. The national SunSmart campaign, which was commissioned by the UK health departments and launched in 2003 by Cancer Research UK, has developed the SunSmart code. It gives the following tips (CRUK, 2007):
- Spend time in the shade between 11am and 3pm;
- Make sure you never burn;
- Aim to cover up with a T-shirt, hat and sunglasses;
- Remember to take extra care with children;
- Then use factor 15+ sunscreen.
The Institute of Cancer Research’s SAFE campaign outlines the signs and symptoms in non-melanoma and melanoma.
Non-melanomas usually appear on areas of skin that are exposed to the sun. The main symptoms to look out for are:
- New sores and lumps that do not heal after a month;
- Spots or sores that bleed, itch, develop a crust or hurt;
- Unexplained skin ulcers.
The SAFE campaign explains that most cases of melanoma start with a change to an area of normal skin, which may look like a new mole. Only one-third of cases develop from existing moles. The institute adds that it is important to remember that melanoma does not appear only in the obvious sites. It can appear anywhere, including on the scalp, on the palms of the hands, on soles of the feet, between the toes and under the nail bed. These forms of melanoma are often the most aggressive and most difficult to treat. Changes to look out for are:
- New or existing moles that appear to be growing or changing shape;
- New or existing moles that are a range of shades of brown and black;
- Moles that are larger than 6mm in diameter;
- Moles with ragged edges.
THE TWO TYPES OF SKIN CANCER
- Non-melanoma usually affects people over 50, although it can affect younger people.
- The only known risk factor for non-melanoma is exposure to UV light, usually from the sun. Other sources of UV light (such as sunbeds) are a risk.
- This type of skin cancer is usually treatable by surgical removal of the visible cancer and, if this occurs in time, it is usually successful and no further treatment is necessary.
- The risk of melanoma increases with age. It is the third most common cancer among people aged 15-39.
- The only known risk factor for melanoma is exposure to UV light, mostly from the sun but also from other sources including sunbeds.
- UV light damages cells of the outer layers of the skin, leading to tanning. In acute cases it causes sunburn, the most obvious evidence of sun-induced skin damage. Prolonged exposure leads to damage to the skin and both forms of damage can drastically increase skin cancer risk.
Source: Institute of Cancer Research (2007).