Skin cancers (Symptoms, Causes & Treatments)

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Skin cancers

Skin cancers are the most common type of cancer in white populations, both in the UK and worldwide.

Most are easy to treat and pose only a small threat to life. But one type, melanoma, is difficult to treat unless detected early.

There are about 7,000 cases of melanoma a year, compared with approximately 100,000 cases of non malignant skin cancer.

But three quarters of skin cancer deaths are from melanoma. Melanoma is related to the common mole and changes in the appearance of moles should alert suspicion.

It is important to seek medical attention quickly because malignant melanoma tends to spread much more rapidly through the bloodstream than the other two types of skin cancer.

If an adult has a growing, changing, brown or black mark which cannot be covered by the blunt end of a pencil, this should be shown to the doctor without too much delay.

Dr Charlotte Proby, a consultant dermatologist for Cancer Research UK, said: "Skin cancers are caused by over-exposure to the sun and particularly to episodes of sunburn.

"Sunburn as a child or young adult increases your risk of skin cancer."

Doctors advise people to cover up in sunny weather, and to avoid sunburn if at all possible.

Symptoms

There are three principal types of skin cancer, and different cancers can have different appearances.

The most common is "Basal cell carcinoma", affecting a type of cell within the top layer of skin.

It is a slow growing cancer, and does not often spread to other parts of the body.

The second type, involving another type of cell in the top layer, is called "squamous cell carcinoma", and again is not known for its aggression.

Melanoma is a different matter - it affects the cells which produce the skin's colouring, and if not treated successfully can spread to affect the liver, lungs or brain.

Doctors warn patients to look out for changes in the appearance of moles, or new growths or sores which fail to heal.

They are rarely painful, although they can be scaly or itchy - so it is mistake to await pain before consulting a doctor.

Changes to look out for in moles include a change in shape, or increase in size, perhaps with the border of the mole or sore being ragged or irregular.

The colouring can vary, and doctors recommend that a growing mole which becomes larger than the flat end of a pencil should be viewed with concern.

To find out if it is skin cancer, and, if so, what sort of skin cancer it is, a doctor will carry out a biopsy, removing all or part of the suspicious growth which is then analysed.

If melanoma is diagnosed, then further tests will be done to see if the cancer has spread beyond the skin to other parts of the body.

This may involve taking x-rays and scans to look at the liver, brain and lungs.

Causes

Although scientists have found that some people may be more vulnerable to skin cancers, the main cause of skin cancer is over-exposure to strong sunlight, and those with lighter skin are far more vulnerable.

It is thought the UV radiation in sunlight causes subtle cell damage which can lead to cancerous changes.

Rates of skin cancer of all sorts are extremely low among dark-skinned people.

Men are more likely to develop cancers on their neck, shoulders and back, whereas in women the cancer is more likely to appear on the legs and arms.

Professor Mackie said: "It's important to know what your risk factors are - for example if you come from a family with a history of skin cancer, you need to be more careful."

If someone has a large number of moles, then they are more likely to develop skin cancer.

Doctors warn people not to spend too long in the sun, and to cover up wherever possible.

Use of suntan lotion has not yet been proven to protect the skin against melanoma.

Treatments

There are wide variety of treatments used to tackle skin cancer, depending on the type, and how far if at all it has spread, or is likely to.

A common operation simply cuts out the affected area under local anaesthetic.

Another method used on smaller cancers is cryosurgery, in which liquid nitrogen is applied to the tumour to freeze it and kill the cells, which simply shrivel and drop off once warmed up.

Heat from a laser is sometimes used to burn away the tumour. Precisely targeted radiotherapy is occasionally pointed at the cancer, as is chemotherapy in the form of a cream.

Some cases of basal cell carcinoma may be suitable for "photodynamic therapy" - which uses a cream to sensitise the tumour - then exposes it to high intensities of light to destroy it.

In the case of melanoma, if there is a suspicion that the cancer may have spread beyond the skin layer, chemotherapy or biological treatment such as interferon may be given to attempt to eradicate skin cancer cells in other parts of the body.