Cancer of the skin
Introduction
Skin cancer is one of the most common forms of cancer, affecting 60,000 people in England and Wales every year.
Types of skin cancer
There are three main types of skin cancer:
- basal cell carcinoma, often known as a rodent ulcer;
- squamous cell carcinoma; and;
- malignant melanoma.
Malignant melanoma is the most serious type of skin cancer because the cancer can spread to other organs in the body (metastasis). Although it is relatively rare - accounting for 10% of all skin cancer cases - malignant melanoma is responsible for the most deaths. In England and Wales, approximately 1,500 people die every year due to malignant melanoma.
Incidence of skin cancer
The number of skin cancer cases has risen over the past ten years. The increase is thought to be due to:
- an increase in the number of people taking holidays in hot climates, and
- the growing popularity of the 'tanned look', and associated use of tanning booths, and sun lamps.
A range of treatment options have proved successful in treating skin cancer. However, the condition can be easily prevented by taking sensible precautions, and avoiding prolonged exposure to sunlight.
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Symptoms
Basal cell carcinoma
Basal cell carcinoma is the most common type of skin cancer and it is also the most easy to treat. As a result, cases of basal cell carcinoma spreading to other parts of the body are very rare.
The symptoms of basal cell carcinoma can appear anywhere on your body but, typically, they appear on areas that have been exposed to the sun, such as your face, arms, legs, and the backs of your hands. Basal cell carcinoma normally appears as:
- a small, smooth bump on the skin, or
- a flat crusty and scaly red spot.
Basal cell carcinoma is usually painless, but you may experience some itchiness. In some cases, you may notice occasional bleeding from the affected area of skin.
Squamous cell carcinoma
As with basal cell carcinoma, squamous cell carcinoma is relatively easy to treat. However, with this type of skin cancer there is a higher risk that it will spread to other parts of your body. It is estimated that between 2-6% of cases of squamous cell carcinoma will spread to other parts of the body.
Squamous cell carcinomas normally appear on sun-exposed parts of your body, such as your face, lips, ears, hands, arms, and legs. They usually appear as:
- a firm red lump, or
- a flat scaly and crusted scab-like lesion.
Malignant melanoma
Malignant melanoma is the most serious type of skin cancer because it affects a deeper layer of skin than the other types, so the risk of the cancer spreading is much higher. Melanomas can appear anywhere on your body, but the back, legs, arms, and face are the most common sites.
The first sign of a melanoma is either the appearance of a new mole, or a change in the appearance of an existing mole. Normal moles are usually a single colour, round, or oval in shape, and are not larger than 6mm (1/4 inch) in diameter.
In contrast, melanomas have an irregular shape, they are more than just one colour, and they are often larger than 6mm (1/4 inch) in diameter. In some cases, the melanoma may also be itchy and occasionally bleed.
A good way to tell the difference between a normal mole and a melanoma is to use the 'ABCDE' checklist where:
- A stands for asymmetrical - the melanoma has two very different halves and is an irregular shape,
- B stands for irregular border - unlike a normal mole, the melanoma has a notched or ragged border,
- C stands for two (or more) colours - the melanoma will be a mix of two or more colours,
- D stands for large diameter - unlike most moles, melanomas are larger than 6mm (1/4 inch) in diameter, and
- E stands for raised elevation - the melanoma will feel slightly raised above the surface of the skin.
See your GP if you notice one, or more, of these
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Causes
Cancer is caused when something affects the genetic material of our cells. This causes the cells to reproduce in an uncontrollable manner producing a lump of tissue, known as a tumour.
There are two types of tumour:
- benign - where the cancerous cells do not have the ability to spread beyond the tumour, and
- malignant - where the cells can spread beyond the tumour and affect other parts of the body.
Over-exposure to sunlight
The leading cause of skin cancer is over-exposure to sunlight. The sun is essentially a gigantic nuclear fusion reactor that pumps out massive amounts of radiation in the form of light and heat.
We are protected from most of this radiation by the earth's atmosphere. However, sunlight contains two wavelengths of radiation that can affect the cells in our skin: Ultraviolet A (UVA) and Ultraviolet B (UVB).
It is thought that UVA causes alterations (mutations) in the cells of our skin that produce the chemical melanin (substance that gives our skin its colour). These mutated cells can then become cancerous and cause melanomas to develop. UVB can also cause mutations in the upper skin layers leading to basal cell and squamous cell carcinomas.
Artificial sources of light, such as sun lamps, and tanning beds, produce UVA so over-use of these appliances will also increase your risk of getting skin cancer.
Genetic causes
Research suggests that you can be genetically predisposed to developing skin cancer (you can inherit it from a family member). And, if you have two, or more, close relatives who have had skin cancer, your chances of developing the condition may be increased further.
Risk factors
Risk factors for developing skin cancer include:
- having pale skin that does not tan easily,
- having red, or blonde, hair,
- having blue eyes,
- having a large number of moles,
- having a large number of freckles, and
- having a condition that suppresses your immune system, such as HIV, or taking medicines that suppress the immune system (immunosuppressants).
All these risk factors will make your skin more sensitive to the effects of the sun.
Other causes
In some rare cases, skin cancer can also be developed from exposure to certain substances including:
- coal tar,
- soot ,
- pitch,
- asphalt,
- creosotes,
- paraffin waxes,
- petroleum derivatives,
- hair dyes,
- cutting oils, and
- arsenic.
You should ensure you wear adequate protective clothing if your profession involves prolonged exposure to any of these substances.
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Diagnosis
Your GP will examine your skin and should be able to decide whether you need to be referred for further assessment. Some GPs take digital photographs of any suspected tumours, so that they can email the pictures to a specialist for assessment.
Biopsy
If skin cancer is suspected, you will be referred to a skin specialist (dermatologist). The dermatologist should be able to confirm the diagnosis by carrying out a physical examination.
However, it is likely that they will also want to perform a biopsy, which is a surgical procedure where either a small part, or all, of the tumour is removed so that it can be studied under a microscope. This will allow the dermatologist to determine what type of of skin cancer you have, and whether there is any chance that the cancer could spread to other parts of your body.
Further tests may be required
Sometimes, skin cancer can be diagnosed and treated at the same time - the tumour can be removed and tested.
If you have basal cell carcinoma, and you have a biopsy that completely removes the tumour, you may not need any further treatment because the cancer is unlikely to spread.
If you have squamous cell carcinoma, and you have a biopsy that completely removes the tumour, further tests may be needed to make sure that the cancer has not spread to another part of your body.
These tests may include a physical examination of your lymph nodes (glands found throughout your body, such as in your neck or arms). If cancer has spread, it may cause your glands to swell.
If the dermatologist feels that there is a high risk of the cancer spreading, it may be necessary to perform a biopsy on a lymph node. For further information about this, see the 'complications' section.
Other tests
Other tests that are sometimes used in cases of skin cancer to check to see if the cancer has spread are described below.
- Chest X-ray,
- a magnetic resonance imaging (MRI) scan that uses a strong magnetic field and radio waves to build up a picture of the inside of your body,
- a computer assisted topography (CAT) scan which is similar to an X-ray, but multiple scans are taken to build up a more detailed '3-D' image of the inside of your body.
- Blood tests.
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Treatment
Many Local Health Boards (LHBs) operate what is known as multi-disciplinary teams (MDTs) for the treatment of skin cancer. An MDT is made up of a number of different specialists including:
- a dermatologist (skin specialist),
- a plastic surgeon,
- a clinical oncologist (a specialist in the non-surgical treatment of cancer using techniques such as radiotherapy and chemotherapy),
- a pathologist (a specialist in diseased tissue),
- a social worker,
- a psychologist, and
- a counsellor.
If you have skin cancer, you may see several, or all, of these professionals as part of your treatment.
Deciding what treatment is best for you can often be confusing. Your cancer team will recommend what they think is the best treatment option, but the decision will be yours.
Before visiting hospital to discuss your treatment options, you may find it useful to write a list of questions that you would like to ask the specialist. For example, you may want to find out what the advantages and disadvantages of particular treatments are.
The type of treatment you will receive will depend on the type, location and progression of your skin cancer. The different treatment options are outlined below.
Surgical excision
Surgical excision is where the surgeon cuts out the cancerous tissue, as well as some surrounding healthy tissue (this is done to ensure that no cancerous cells remain in the skin).
If a surgical excision is likely to leave significant scarring, it may be done in combination with a skin graft. A skin graft involves removing a patch of healthy skin which will usually be taken from a part of your body where any scarring cannot be seen, such as your back. It is then connected, or grafted, to the affected area.
Curettage and electrocautery
Curettage and electrocautery is a similar technique to surgical exclusion, but it is only suitable for cases where the affected area of tissue is quite small. The surgeon will use a small, spoon-shaped blade to remove the tumor, and then an electric needle will be used to kill the cells surrounding the wound to ensure that any remaining cancerous cells are removed. The procedure may need to be repeated two or three times, to ensure that the cancer is completely removed.
Radiotherapy
Radiotherapy is often used to treat basal cell and squamous cell carcinomas in cases where surgical excision would leave an unacceptable level of disfigurement - for example, where tumours are present on the face.
Radiotherapy involves using low doses of radiation to destroy the cancerous cells. The level of radiation involved is perfectly safe but, afterwards, your skin may feel sore for a few weeks.
Radiotherapy is also sometimes used after surgical excision to ensure that the cancer does not return.
Cryotherapy
Cryotherapy is sometimes used to treat skin cancers that are in their early stages. The technique uses liquid nitrogen to freeze the affected tissue which causes the area to scab over.
After about a month, the scab, containing all the cancerous cells, falls off the skin. The treatment may leave a small white scar on the skin.
Mohs' surgery
Mohs' surgery is used to treat skin cancer when it is felt that there is a high risk of the cancer spreading, or returning. It involves removing the tumour piece by piece, so that each piece can be checked immediately for the presence of cancerous cells.
The benefit of this approach is that it minimises the removal of healthy tissue and therefore reduces any scarring. It is also a good way of ensuring that the cancer will not spread to other areas of your body.
The disadvantage of Mohs' surgery is that that technique is extremely complicated and there are only a small number of surgeons who are trained to carry it out. It is therefore only available at a few specialist cancer centres in the UK.
You may be referred to one of the centres, if it is felt that it is the only viable treatment option for your condition.
Chemotherapy
Chemotherapy involves using medicines to kill cancerous cells. In the case of skin cancer, chemotherapy is only recommended when the tumour is contained within the top layer of the skin.
This type of chemotherapy involves applying a cream, containing cancer-killing medicines, to the affected area. As only the surface of the skin is affected, you will not experience the side effects associated with other forms of chemotherapy, such as vomiting, or hair loss. However, afterwards, your skin may feel sore for several weeks.
Photodynamic therapy (PDT)
Photodynamic therapy (PDT) is a relatively new treatment that is available on the NHS for the treatment of basal cell carcinoma. It involves using a special cream containing a medicine known as 5- aminolaevulinic acid (5-ALA). 5-ALA makes the skin very sensitive to light.
After the cream has been applied, a strong light source is shone on the affected area of your skin which kills the cancerous cells. PDT may cause a burning sensation and around 2% of people will be left with some superficial scarring.
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Complications
Metastasis
Metastasis is a term that describes the process when cancer has spread to other parts of your body. Cancer cells tend to initially spread through the lymphatic system.
The lymphatic system is similar to the blood circulation system in that it uses tubes that connect to all parts of your body. However, instead of carrying blood, the lymphatic system carries clear fluid called lymph. The lymphatic system performs several important functions, such as helping fight infection, and draining excess fluid from tissue.
The lymphatic system contains many small shape nodes, or glands. If the cancer has metastasized (spread), cancerous cells will initially be found in the lymph node that is nearest to the affected tissue.
If your cancer treatment team feels that there is a significant risk that the cancer has spread, the nearest lymph nodes to the site of your tumour will be checked. This is usually done using a process known as a sentinel lymph node biopsy.
Sentinel lymph node biopsy
A sentinel lymph node biopsy begins with the surgeon injecting a radioactive blue dye into the site of your tumor. The surrounding lymph nodes are then scanned to find out which was the first node to take up the dye. This is known as the sentinel node.
The sentinel node is removed and tested for the presence of cancerous cells. If the test is negative, it is extremely unlikely that the cancer has spread. However, if the test is positive, all of the lymph nodes in the surrounding area will be removed. This is known as a block dissection.
By removing potentially cancerous lymph nodes, it is hoped that the spread of cancer will be halted.
Following a block dissection, you should be able to return to normal activities about 14 days after the procedure. However, there is a chance that the removal of lymph nodes will cause a condition called lymphoedema.
Lymphoedema
Lymphoedema is a condition that causes swelling in a part of the body. It often occurs when lymph nodes have been removed from a limb.
One of the functions of the lymphatic system is to drain away excess fluid from tissue. If your lymph nodes are surgically removed, or damaged by cancer, the draining function of your lymph nodes may be disrupted, causing swelling to occur. The affected part of the body may become stiff, sore, and be difficult to use.
Although lymphoedema cannot be cured, a range of treatments are available, such as special compression clothing, and massage techniques, to help control the symptoms.
Recurring skin cancer
If you have had a skin cancer in the past, particularly a melanoma, there is a chance that the condition may return. The chance of your skin cancer returning is increased if your previous cancer was particularly wide-spread and severe.
If your cancer team feel that there is a significant risk of your cancer returning, it is likely that you will require regular check-ups to monitor your health. You will also be taught a range of self-examination techniques that you can use to check for any tumors on your skin.
It is also important that you take steps to prevent over-exposure to the sun. See the 'prevention' section for further details about this.
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Prevention
Avoid over-exposure to the sunlight
The best way to prevent skin cancer is to avoid over-exposure to the sun.
This is not to say that you should avoid sunlight all together. Sunlight promotes the production of Vitamin D, which is needed by the body to produce calcium. Also, recent research has shown that Vitamin D can prevent other types of cancer, and cardiovascular diseases (conditions that affect the blood flow), such as strokes.
If you have a condition that suppresses your immune system, or you are taking a class of medicines known as immunosuppressants, you may be advised to avoid sunlight. This is because you will have an increased risk of getting skin cancer. If this is the case, taking Vitamin D supplements to compensate for the lack of sunlight may be beneficial. Your GP will be able to advise you about this.
When spending time in the sun, you should do so in moderation. You do not need to get a suntan to enjoy the benefits of Vitamin D.
The advice outlined below will help you to stay safe in the sun.
Avoid the sun when it is at is hottest
The sun is usually at its hottest around midday, but it can also be very strong, and have potentially damaging effects, in the morning and during late afternoon and early evening. You should therefore avoid spending long periods in the sun, at any time during the day, and make sure that you wear the appropriate sunscreen for your skin type (see below).
Use sunscreen
When buying sunscreen, make sure that it is suitable for your skin type, and blocks both ultraviolet A (UVA) and B (UVB) radiation. In most cases, sun protection factor 15 (SPF 15) should be suitable for the British climate, but you may require a higher SPF in hotter climates.
Sunscreen should be applied around 15 minutes before going out into the sun, and reapplied every two hours. If you are planning to spend time in the water, you should use a waterproof sunscreen.
Dress sensibly
If you cannot avoid spending long periods of time in the sun - for example, if you have a job that requires you to work outside, you should wear clothes that will provide protection from the sun. This should include a hat to protect your face and scalp, and sunglasses to protect your eyes.
Take extra care to protect babies and children
Compared to adults, the skin of babies and children is much more sensitive, and repeated exposure to sunlight could lead to skin cancer developing in later life. Before going out into the sun, make sure that your children are dressed appropriately, and that they are wearing a hat, and a high factor sunscreen.
Prevent rather than cure
If you cannot avoid spending prolonged periods of time in the sun, it is very important to ensure that you do not get sunburnt. Getting sunburnt is dangerous, and if you do not take precautions to prevent it, your skin cells will be damaged by the intense levels of radiation produced by the sun. Each time that your skin cells are exposed to intense levels of radiation, the likelihood of a mutation occurring increases. This can lead to skin cancer developing , either in the short-term, or many years in the future.
Tan sensibly
Most health professionals will tell you to avoid sunbathing altogether because even a tan can increase your risk of developing skin cancer. However, if you are determined to get a tan, make sure that you do it gradually by limiting the amount of time you spend in spend in the sun each day. When you first begin to tan, limit your exposure to the sun to 30 minutes, and then gradually increase your time in the sun by 5, or 10, minutes per day.
Sunbeds and Sunlamps
The UK's leading professional body on skincare, the British Association of Dermatologists, recommends that people should not use sunbeds, or sunlamps.
Sunbeds and lamps can be more dangerous than natural sunlight because they use a concentrated source of ultraviolet A (UVA) radiation.
Ultraviolet A radiation can increase your risk of developing malignant melanomas - the most dangerous type of skin cancer. Sunbed and sunlamps can also cause premature aging of the skin.
It is even more important to avoid using sunbeds and sunlamps if you are in one of the high risk groups for developing skin cancer.
Risk factors include:
- having pale skin that does not tan easily,
- having red, or blonde, hair,
- having blue eyes,
- having a large number of moles,
- having a large number of freckles, and
- having a condition that suppresses your immune system, such as HIV, or taking medicines that suppress the immune system (immunosuppressants).
If you insist on using sunbeds, or sunlamps, the Health and Safety Executive recommend that you do not have more than 20 tanning sessions per year. Each session should last no more than ten minutes.
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