Skin cancer is the most common type of cancer among white or Caucasian populations worldwide. Most are easy to treat and pose only a small threat to life, but one type, malignant melanoma, is difficult to treat unless detected early.
Skin Cancer Symptoms
There are three principal types of skin cancer, which can have different symptoms and appearances. Basal cell carcinoma (BCC) is the most common type of skin cancer, accounting for 75 per cent of non-melanoma skin cancers. It affects a type of cell within the top layer of skin (epidermis), and is a slow-growing cancer that doesn’t usually spread to other parts of the body.
BCC affects all sun-exposed areas of the body, especially parts of the face such as the nose, forehead, cheeks and ear lobes. The main symptom is a small, painless, pink/brownish-grey lump, with a smooth surface, blood vessels and a waxy or pearl-like border. The lump grows, developing a central depression (or ulcer) with rolled edges. They are often symptomless but may be itchy and bleed. BCC’s usually develop in mid to late life.
Squamous cell carcinoma (SCC) involves another type of cell in the top layer of skin or epidermis. It usually affects the head, neck or back of the hands and the main symptom is an area of thickened, scaly skin that develops into a painless, hard lump, reddish brown in colour with an irregular edge. The lump becomes a recurring ulcer and doesn’t heal. Occasionally SCCs form on the vulva or around the anus.
These two types (BCC and SCC) are known as non-melanoma skin cancer (along with a few other much more rare types of skin cancer). They are usually slow growing, occur on sun-exposed areas of the skin and rarely spread.
Malignant melanoma skin cancer can occur anywhere on the body and is more dangerous. It’s related to the common mole and changes in the appearance of moles on your body should be checked by your GP.
Malignant melanoma develops from the pigmented cells that produce the skin’s colouring, in the outer layer of the skin (the epidermis) usually within a mole. It tends to spread much more rapidly down through the layers of skin and then through the bloodstream than the other two types of skin cancer and is much more resistant to treatment. If not caught early or treated successfully it can spread to the liver, lungs or brain.
The main symptom is a quick-growing, irregular, dark-coloured spot on previously normal skin or in an existing mole that changes size, colour, develops irregular edges, bleeds, itches, crusts or reddens. 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 straight away. People with darker skin are less likely to get a melanoma but it may still occur, usually on the palms of the hands, soles of the feet or under a nail.
Occasionally, melanoma may present with swollen lymph glands or rarely in unusual places including inside the mouth or eye. 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.
Skin Cancer Causes
The main cause of skin cancer is over-exposure to the sun’s harmful UV rays. A suntan isn’t healthy – it’s a sign of skin damage. It’s thought the UV radiation in sunlight causes subtle cell damage which can lead to cancerous changes. Scientists have found that those with lighter skin are far more vulnerable to skin cancers, because they produce less pigment which protects against the sun. Rates of skin cancer of all sorts are extremely low among dark-skinned people.
Non-melanoma skin cancer results from prolonged sunlight exposure over many years, which is why they mostly occur in later life. The main cause of malignant melanoma is exposure to short periods of intense sunlight. Episodes of sunburn, especially in childhood, are particularly linked to an increased risk of malignant melanoma. Men are more likely to develop cancers on their neck, shoulders and back, whereas in women they’re more likely to appear on the legs and arms.
Skin Cancer Diagnosis
Diagnosis of skin cancer can usually be made by your doctor or hospital specialist by simple skin examination. Sometimes, the skin cancer will need to be removed by a small operation or biopsy; both for treatment and lab testing. Other routine tests, including X-rays and scans aren’t usually required.
Skin Cancer Treatment
radiotherapy for skin cancer
Non-melanoma skin cancers are usually treated by an operation to cut out the affected area under local anaesthetic (larger tumours in difficult areas or needing a skin graft may need a general 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. Some cases of basal cell carcinoma may be suitable for photodynamic therapy, which uses a cream to sensitise the tumour and then exposes it to high intensities of light to destroy it.
Radiotherapy for Skin Cancer
Radiotherapy may also be used for both BCCs and SCCs especially in certain cases such as when the cancer covers a large area, is in an area of skin that is difficult to cut out or in the frail elderly. Chemotherapy or drug treatments may be used in some cases too. A newer type of treatment, called immunotherapy, stimulates the cells of the immune system to attack and kill the skin cancer cells. This may be useful for SCCs in the nose or mouth, for example or a BCC in the top layer of the skin. It is also used for a condition called Actinic Keratosis which is a very early stage of skin cancer.
Surgery for Skin Cancer
Because melanoma is such an aggressive cancer, people with it are usually looked after by a team of specialists called a multidisciplinary team. In very early and superficial melanoma surgery alone, with careful surveillance follow-up afterwards may be all that is needed. But the larger the melanoma, the wider the piece of skin that must be removed from where it started in order to ensure that no cancerous cells were left behind and further operations may be needed. If there is a suspicion that the cancer may have spread beyond the skin layer, nearby lymph glands may need to be removed and examined under the microscope for spread of cancer cells.
Chemotherapy for Skin Cancer
Chemotherapy or biological treatment such as interferon may be given to attempt to eradicate microscopic spread of skin cancer cells to other parts of the body, especially in melanoma. These are known as adjuvant therapy but it is not yet clear how effective they are at preventing recurrence of a melanoma, so you would only be offered these treatments as part of a research trial.
If a melanoma has already spread, further surgery or laser treatment may be used to remove or destroy the cancerous cells. Chemotherapy and radiotherapy are sometimes used too. Biological therapies, which use chemical substances naturally made by the body such as antibodies, may be used in advanced melanoma while other research is looking at vaccines against the cancer.
In non-melanoma skin cancer, cure rates are very high and deaths uncommon
Skin Cancer Prevention
The best way to prevent skin cancer is to avoid too much time in the sun. You don’t have to be sunbathing to get burned. You can get too much sun while walking to the shops, driving a car with the windows down, even under light cloud cover. Time of day and location are important too. The intensity of UV radiation increases during the middle of the day, between April to September, nearer the equator and at higher altitudes.
How to protect yourself and your children:
- Stick to the shade between 11am and 3pm
- Cover up with clothes, a wide brimmed hat and sunglasses
- Apply a high-factor sunscreen (minimum SPF15 and three stars) regularly
- Drink plenty of water to avoid overheating
- Avoid using sun lamps or sunbeds
Watch those moles
Many moles aren’t cancerous, but it’s vital to keep an eye on any you have. Watch out for moles that change shape or colour, become bigger, itchy or inflamed, or that weep or bleed. If you notice any changes or are worried, get them checked by a doctor.
- A stands for Asymmetry (i.e if the mole become irregular and asymmetrical in its shape)
- B is for Border – if the edges of the mole become irregular or jagged (smooth edged moles are less likely to be abnormal)
- C stands for Colour – particularly if the mole becomes uneven in its colour and develops several shades of pigment
- D is for Diameter – a mole that grows larger than the eraser on the end of a pencil (more than 6mm diameter) should be checked by a doctor
- E is for Evolution, which means change – be wary of any persistent change in a patch of skin, lump or mole