Malignant Melanoma

 

What is a malignant melanoma?

The cells in the skin that cause skin tanning in response to sunlight are called melanocytes. Sometimes these cells can become cancerous (malignant), and this results in a type of skin cancer called a malignant melanoma. Although a melanoma starts in the skin it has the ability to spread to other organs of the body, such as the lungs and liver, if not caught early and treated. There were about 4,000 cases of malignant melanomas in 1992 in England and Wales, and the number of cases is increasing by about six per cent per year. This increase is almost certainly due to the fashion for tanned skin and lack of care in protecting the skin from the sun's rays.

Who gets malignant melanomas?

Almost anyone can develop a malignant melanoma, although they are rare under the age of puberty and very unusual in dark-skinned people (probably because these people have a certain amount of natural protection against the sun). They are most common in the 40 to 60 age group and in fair-skinned people, but everyone should be aware of the chance of developing a melanoma. People with lots of moles are at higher risk of having malignant melanomas and there is also a condition called 'familial melanoma syndrome', where members of the same family are especially prone to this condition and therefore need special screening.

Why does it occur?

The most common cause of malignant melanomas is exposure to ultraviolet light (ie the sun), which explains the high rate of this condition in white people living in hot climates such as Australia, compared with similar people living in cooler climates. There seems to be a connection between severe sunburn as a child and a higher risk in later life of developing melanomas.

 

Where do malignant melanomas appear?

A malignant melanoma can occur anywhere on the body, not just in places exposed to the sun. However, for some reason half of all malignant melanomas in women occur on the lower leg, whereas the trunk (the main part of the body) is the most common site in men. Afro-Caribbeans are especially prone to developing malignant melanomas on the fingers and toes, usually around the area of the nails. Malignant melanomas can even arise in the groin, the palms of the hands and soles of the feet, and also beneath the nails although these are all fairly unusual places.

What does a malignant melanoma look like?

Malignant melanomas have a variety of appearances and can arise as a new 'mole' or from a pre-existing mole that has been present for some time. Usually, but not always, they are pigmented - either black or a mixture of black and brownish colours, and they tend to have an irregular outline and usually grow in size fairly quickly. Sometimes they develop 'satellite lesions' which are little moles around the big one and have a tendency to bleed or ulcerate spontaneously. However, despite this general description it can be very difficult to distinguish a malignant melanoma from a benign mole, so if a person is in any doubt about the appearance of a mole they should see their doctor.

There are some things that everyone can look out for to alert them to the possibility of a malignant melanoma. Be alert to a new or existing mole that shows any of the following:

  • rapid growth;
  • change in shape (especially if the margins of the mole are not clearly defined);
  • change in colour (especially if there are a number of different colours within the same mole such as browns and blacks);
  • spontaneous bleeding or ulceration; or
  • satellite lesions as described above.

Moles that are less than 0.5 cm in diameter and have a clear edge are unlikely to be a melanoma. Itching is often mentioned as a sign to look out for, which indeed it is, but many benign moles itch. Almost any mole will bleed if caught in clothing or accidentally cut, but melanomas may ooze or bleed spontaneously.

 

What is the treatment for malignant melanomas?

Melanomas can be cured if they are detected and removed early enough. If the doctor thinks a mole may be malignant, he or she will refer the patient to a skin specialist. If the specialist agrees with the assessment, he will arrange to have the mole removed along with a margin of healthy skin around the mole to ensure that the whole lesion has been removed. The tissue is then examined under a microscope to confirm the diagnosis and to assess how deeply the melanoma has grown down into the skin. This helps the doctors to decide if further treatment is required, and if so, what kind of treatment.

For instance, further surgery to remove more tissue from around the site of the mole may be done, along with removal of any local lymph nodes if it is thought that the melanoma has spread to these. If a lot of tissue is removed, skin grafting may be required. Skin is removed from another area of the body (usually the thigh or buttock) to help to cover the wound in a way which leaves the least scar tissue.

What follow up is required after treatment?

The individual will be seen regularly by the specialist firstly to ensure that the wound has healed satisfactorily, and then to check for any signs of recurrence or spread of the melanoma. The follow up may involve a simple examination, or sometimes special x-rays or blood tests may be done. If the melanoma is found to have spread to other parts of the body, further treatment with radiotherapy (x-ray treatment) or chemotherapy (powerful cancer-killing drugs) may be used to slow down the rate of spread and shrink any new deposits. Unfortunately, if spread has occurred, the outlook is not good, and ultimately the doctors may recommend 'palliative treatment'. This is medication aimed at treating the symptoms of the illness since at this stage cure is very unlikely. Palliative treatment may include radiotherapy, chemotherapy, painkillers or a whole variety of measures to give the individual the best possible quality of life.

What can be done to prevent malignant melanomas?

Most people will now know about the link between excessive exposure to the sun and the development of skin cancers including malignant melanomas. Some of the following simple measures can therefore be used:

  • Avoid going out in the sun in the middle of the day when the sun is at its most powerful. A good rule is not to go out when your shadow is smaller than you are.
  • Cover the skin areas with long sleeved clothing, and wear a hat.
  • Use a high-factor sun cream, and ensure this is re-applied after swimming. Although it has so far not been conclusively proven that sun creams protect against skin cancer, logic tells us that it is likely to do so since we know that episodes of sunburn may predispose people to skin cancer.
 

Are there any new developments in the treatment of malignant melanomas?

Research is being done into what is called 'immunotherapy', which is an area of medicine which looks at the possibility of 'training' the body into fighting off melanomas in the same way as it fights off viral illnesses. One day this may result in a vaccine to prevent the occurrence of melanomas in the first place.

Where can I obtain further information?

Macmillan Cancer Support
89 Albert Embankment
London
SE1 7UQ
Telephone: 0808 808 00 (freephone Helpline 09:00 to 20:00)
Website: www.macmillian.org.uk