Non-melanoma skin cancer refers to a group of skin cancers that affect the upper layers of skin. The term 'non-melanoma' distinguishes these generally more common kinds of skin cancer from the rarer, aggressive skin cancer known as melanoma.
Types of non-melanoma skin cancer
Non-melanoma skin cancers are usually named after the type of skin cell from which they develop. The two most common types of non-melanoma skin cancer are:
- basal cell carcinoma
- squamous cell carcinoma
The information in this section focuses on these types of non-melanoma skin cancer.
Other rarer types include:
- Kaposi's sarcoma
- cutaneous T-cell lymphoma (also known as Mycosis fungoides)
- Merkel cell cancer
The most significant risk factor for developing either basal cell carcinoma or squamous cell carcinoma is overexposure to sunlight. The use of sunbeds and sunlamps can also increase your risk of developing non-melanoma skin cancer, as well as the most serious type of skin cancer, melanoma.
How common is non-melanoma skin cancer?
Non-melanoma skin cancer is one of the most common types of cancer in the world. There are an estimated 700 new cases of non-melanoma skin cancer every year in Ireland.
Basal cell carcinomas account for 75% of all cases of skin cancer, and squamous cell carcinomas account for 20% of all cases.
The outlook for non-melanoma skin cancer is usually very good. Unlike most other types of cancer, there is a considerably lower risk that the cancer will spread to other parts of the body (known as metastasis).
It is estimated that basal cell carcinoma will spread to other parts of the body in less than 0.5% of cases. The risk is slightly higher in cases of squamous cell carcinoma, which spreads to other parts of the body in about 4% of cases.
Approximately 90% of people with basal cell carcinoma will achieve a complete cure. Between 70% and 90% of people with squamous cell carcinoma will be completely cured.
Treatments for non-melanoma skin cancer include surgery, radiotherapy and chemotherapy.
Basal cell carcinoma
Basal cell carcinoma (or BCC for short) appears as a bump or discoloured patch of skin that does not heal. The bump or patch is a cancer. Sometimes this is referred to as a tumour, which just means lump but is often used as an alternative word for cancer. The bump is usually a pearly-white colour or 'waxy' looking and may contain visible blood vessels. The discoloured patch of skin is flat and scaly and can have either a flesh-coloured or brown appearance.
Basal cell carcinomas can grow to cover 10-15cm (4-6 inches) of skin. Both the bumps and discoloured skin patches can develop anywhere on your body, but they usually appear on parts of the body that have been exposed to the sun. Tumours usually develop on the face, ears and neck, while the discoloured skin patches usually develop on the chest and back. Basal cell carcinomas are usually painless, although they may itch or bleed.
Squamous cell carcinoma
Squamous cell carcinoma (or SCC for short) appears as a firm red lump or a flat, scaly and crusted scab-like lesion that does not heal. These lumps or lesions are tumours. The lump or lesion (which just means something abnormal) usually appears on parts of the body exposed to the sun, such as the face, lips, ears, hands, arms and legs. Less commonly, they can develop inside the mouth, on the genitals or in the anus.
When to get medical advice
If you develop a bump, lesion or skin discolouration that shows no signs of healing or continues to grow after a few weeks, see your GP.
The body is made up of millions of different cells. Cancer happens when some of the cells multiply in an abnormal way. When cancer affects organs and solid tissues, it causes a growth called a tumour to form. Cancer can occur in any part of the body where the cells multiply abnormally.
How does cancer spread?
Left untreated, cancer can quickly grow and spread, either in the skin or the blood or to other parts of the body. This usually happens through the lymphatic system.
The lymphatic system is a series of glands that are spread throughout the body and linked together in a similar way to the blood circulation system. If you have a cold or flu, the glands that come up in the neck are the lymph glands (also called lymph nodes). The lymph glands produce many of the cells that are needed by your immune system.
Once the cancer reaches your lymphatic system, it can spread to any other part of your body, including your bones, blood and organs.
Non-melanoma skin cancers
The leading cause of all types of skin cancer - melanoma and non-melanoma - is exposure to sunlight.
Sunlight contains ultraviolet (UV) light that can affect the skin. There are two main types of UV - ultraviolet A (UVA) and ultraviolet B (UVB). Both UVA and UVB damage skin over time, making it more likely for skin cancers (including melanomas) to develop. Artificial sources of light, such as sunlamps and tanning beds, may also increase your risk of developing melanoma skin cancer
Repeated sunburn, either by the sun or artificial sources of light, will also make your skin more vulnerable to non-melanoma skin cancer.
Research suggests that if you have two or more close relatives who have had non-melanoma skin cancer, your chances of developing the condition may be increased.
Risk factors for developing all types of skin cancer include having:
- pale skin that does not tan easily
- red or blonde hair
- blue eyes
- a large number of moles
- a large number of freckles
- an area of skin that has been previously damaged by burning or radiotherapy treatment
- a condition that suppresses your immune system, such as HIV
- medicines that suppress your immune system (immunosuppressants)
All these risk factors will make your skin more sensitive to the effects of the sun.
Your GP will examine your skin and decide whether you need to be referred for further assessment. Some GPs take digital photographs of any suspected tumours so they can email them to a specialist for assessment.
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, they will probably also do a biopsy - a surgical procedure where either a part or all of the tumour is removed and studied under a microscope. This allows the dermatologist to determine what type of skin cancer you have and whether there is any chance that the cancer could spread to other parts of your body.
Sometimes, skin cancer can be diagnosed and treated at the same time. In other words, the tumour can be removed and tested and you may not need any further treatment because the cancer is unlikely to spread.
In some rare cases of squamous cell carcinoma, further tests may be needed to make sure 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). If cancer has spread, it may cause your glands to swell. This is because cancer can spread to other parts of your body through your lymphatic system.
If the dermatologist thinks there is a high risk of the cancer spreading, it may be necessary to perform a biopsy on a lymph node. Finding cancerous cells in a nearby lymph node would suggest that the squamous cell carcinoma has started to spread to other parts of your body.
- An ulcer is a sore break in the skin or on the inside lining of the body.
People with cancer should be cared for by a multidisciplinary team (MDT). This is a team of specialists who work together to provide the best treatment and care.
The team often consists of a dermatologist, a plastic surgeon, an oncologist (a radiotherapy and chemotherapy specialist), and a pathologistOther members may include a dietitian and occupational therapist, and you may have access to clinical psychology support.
If you have non-melanoma skin cancer, you may see several (or all) of these professionals as part of your treatment.
When deciding what treatment is best for you, your doctors will consider:
- the type of cancer you have
- the stage and grade of your cancer (how big it is and how far it has spread)
- your general health
Your cancer team will recommend what they think is the best treatment option but, ultimately, 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.
Surgical excision is where the surgeon cuts out the cancer, as well as some surrounding healthy tissue to ensure that the cancer is completely removed.
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. A flap is where nearby skin is moved into fill the wound.
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 excision, but is only suitable for cases where the cancer is quite small.
The surgeon will scrape and cauterise (burn) the tumour a number of times, usually two or three, which is done all at the same time, to ensure that the cancer is completely removed.
Cryotherapy uses cold treatment to destroy the cancer. It is sometimes used for non-melanoma skin cancers that are in their early stages. Liquid nitrogen is used to freeze the cancer, and this causes the area to scab over.
After about a month, the scab containing the cancer will fall off your skin. Cryotherapy may leave a small white scar on your skin.
Mohs' micrographic surgery
Mohs' micrographic surgery (MMS) is used to treat non-melanoma skin cancers when it is felt that there is a high risk of the cancer spreading or returning, or the cancer is in an area where it would be important to remove as little skin as possible, such as the nose or eyes. It involves removing the tumour bit by bit, as well as a small area of skin surrounding it. This minimises the removal of healthy tissue and reduces any scarring.
Each time a piece of tissue is removed, it is checked for the presence of cancer. The procedure may need to be repeated two or three times in the same operating session, to ensure that the cancer is completely removed.
Chemotherapy involves using medicines to kill cancerous cells. In the case of non-melanoma 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, your skin may feel sore for several weeks afterwards.
Photodynamic therapy (PDT)
Photodynamic therapy (PDT) uses light to treat basal cell carcinoma. It involves a cream which 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 cancer. PDT may cause a burning sensation, and around 2% of people who have this treatment will be left with some superficial scarring.
Imiquimod cream is a treatment for basal cell carcinoma with a diameter of less than 2cm (0.8 inches). Imiquimod encourages your immune system to attack the cancer in the skin.
Common side effects of imiquimod include:
- flaking or peeling skin
- thickening of your skin
Less common and more serious side effects of imiquimod include:
- blistering or ulceration of your skin
Wash the cream off and contact your GP if your skin blisters or you develop ulcers after using imiquimod.
Radiotherapy involves using low doses of radiation to destroy the cancer. The level of radiation involved is perfectly safe. However, your skin may feel sore for a few weeks after radiotherapy.
Radiotherapy is sometimes used to treat basal cell and squamous cell carcinomas if surgery would be unsuitable, or where the cancer covers a large area or would leave an unacceptable level of disfigurement, such as if the cancer is on the face.
Radiotherapy is sometimes used after surgical excision to try to prevent the cancer coming back. This is called adjuvant radiotherapy.
Recurring non-melanoma skin cancer
If you have had non-melanoma skin cancer in the past, there is a chance that the condition may return. If your original skin cancer was large and severe, there is a chance it may recur. Usually this is near the original scar or rarely in nearby lymph nodes.
If your cancer team feels that there is a significant risk of your non-melanoma skin cancer returning, you will probably 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 tumours on your skin.
It is also very important that you take steps to prevent overexposure to the sun. See Skin cancer (non-melanoma) - prevention for more information.
Once you have developed one skin cancer you are at higher risk of developing other new skin cancers of the same type, and also the other forms of skin cancer.
The best way to prevent all types of skin cancer is to avoid overexposure to the sun.
Avoid the sun when it is at its hottest
The sun is usually at its hottest around midday, but it can also be very strong and have potentially damaging effects at other times. Avoid spending long periods in the sun during the day, spend time in the shade and cover up with clothes as well as sunscreen.
If you cannot avoid spending long periods in the sun - for example if you have a job that requires you to work outside - 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.
When buying sunscreen, make sure it is suitable for your skin type and blocks both ultraviolet A (UVA) and ultraviolet B (UVB) radiation.
Sunscreen should be applied around 15 minutes before you go out into the sun and reapplied every two hours. If you are planning to spend time in the water, use a water resistant sunscreen and be aware that no sunscreen is waterproof.
Take extra care to protect babies and children. The skin of babies and children is much more sensitive than adult skin 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.
If you spend time in the sun, avoid getting sunburnt. Once you are burnt, the damage has already been done to your skin as your skin has received a dangerous level of radiation. Every time the skin is exposed to radiation, this increases the chance of a cancer occurring, possibly many years in the future.
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, do it gradually by limiting the amount of time you spend in the sun each day and by wearing sunscreen. When you begin to tan, limit your exposure to the sun to 30 minutes, then gradually increase it by five or 10 minutes a day.
Sunbeds and sunlamps
The Irish Association of Dermatologists is Ireland's leading professional body on skincare. They recommend that people do not use sunbeds or sunlamps.
Sunbeds and lamps can be more dangerous than natural sunlight because they use a concentrated source of ultraviolet (UV) radiation.
UV radiation can increase your risk of developing melanomas, the most dangerous type of skin cancer. Sunbeds and sunlamps can also cause premature ageing 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 (see Skin cancer, non-melanoma - causes).It is strongly recommened that you should not use UV tanning equipment if:
- You have fair, sensitive skin that burns easily or tans slowly or poorly.
- You have a history of sunburn, particularly in childhood.
- You have lots of freckles or red hair.
- You have lots of moles.
- You are taking medicines or using creams that make your skin sensitive to sunlight.
- You have a medical condition that is made worse by sunlight.
- You or someone in your family has had skin cancer.
- Sunlight has already badly damaged your skin.