Information on Malignant Melanoma
There are three main types of skin cancer. These are:
- Basal cell carcinoma,
- Squamous cell carcinoma, and
- Malignant melanoma.
Although basal cell and squamous cell carcinomas are much more common, malignant melanoma is a much more aggressive condition. Consequently, the risk of this disease spreading to other parts of the body is much higher. Basal cell and squamous cell skin cancers are discussed in another section.
Types of malignant melanoma
Malignant melanoma can develop from skin abnormalities such as moles and freckles, or more commonly, from apparently normal skin. However, the development of malignant melanoma is not restricted solely to the skin. On occasion it can develop in the mouth, under the fingernails, within your body or even in the eye. As mentioned above, malignant melanoma can also spread to other areas of the body via the bloodstream or lymphatic system or by spreading across the skin.
Malignant Melanoma is found in several forms, the most common being superficial spreading melanoma. Other forms include the fast growing nodular melanoma, acral melanoma (often found on the soles of the feet, palms of the hands or around the toenails), the slow growing lentigo maligna melanoma (usually found on the face) and ocular melanoma (affecting the eye).
The causes of malignant melanoma
Ultraviolet (UV) rays from the sun (and even sunbeds to a lesser degree), are thought to be the primary cause of malignant melanoma, although this condition may occur in people who haven’t received excessive exposure (perhaps due to a genetic predisposition to the disease).
Those at highest risk are people who spend a lot of time outdoors (perhaps as part of their occupation). If you are someone who burns easily (if you have fair skin, fair hair or red hair and blue eyes), experts recommend that you should use sun cream with a high skin protection factor such as 15 or above whilst you are outdoors.
It is thought that high exposure to the sun when you are younger can cause malignant melanoma and other skin cancers up to 20 years later. Consequently, the most common age to develop skin cancers is between 40 and 60 years old.
Malignant melanoma is more common in women than men and the areas in which it develops does vary between the sexes. More than half of malignant melanomas in women occur on the legs or feet, whereas only a quarter of male cases are in this area. In men the most common area to develop a malignant melanoma is on the torso – mainly on the back or neck.
The symptoms of malignant melanoma
Two thirds of melanomas develop from normal looking skin, with less than a third developing in existing moles. On that basis the most important symptoms to look for are new skin abnormalities. Early detection of malignant melanomas is so important that we have even provided a section on skin self-examination that you should follow once a month – particularly if you have received excessive exposure from the sun in the past.
If you do have existing skin blemishes or moles, you should be vigilant for any of the following changes:
- Change in size – a mole may spread outwards over the skin or become textured or lumpy.
- Change in shape – melanomas often have an irregular, ragged edge as opposed to the smooth round shape of a normal mole.
- Change in colour – any development of an inflamed or reddish edge to a mole is a warning sign. The same is true if it becomes darker or exhibits different shades of colour.
- Crusting, irritation or bleeding occur in only a limited number of cases but can be an important symptom to note.
In cases of malignant melanoma of the eye, although external changes may not be obvious you may experience flashing lights, blurred vision and shadows.
Of course, not all skin abnormalities become cancerous, but it is vital that you take note of any of the above and inform your doctor immediately if you have any concerns. Early detection of malignant melanoma increases the success rate of treatment.
Methods of diagnosis
If your doctor suspects malignant melanoma or wishes to rule it out, he or she will refer you to a dermatologist to offer their expert opinion.
Often a visual examination is sufficient to indicate the likelihood of malignancy, but an excision biopsy (performed under local anaesthetic) will provide a definitive result.
Having removed the malignant melanoma, the depth of the tumour is assessed to determine the extent of the disease. The thinner the melanoma, the greater the success rate of treatment. Tumours with a thickness of less than 2 millimetres have the best cure rate and little chance of spread to other parts of the body.
If your melanoma is greater than 2 millimetres, your doctor may want to run a number of other tests to see if the condition has spread to other parts of the body.
These tests may include (but are not limited to):
- Blood tests.
- Chest X-ray.
- CT scan (CAT scan).
- Isotope bone scan.
- Magnetic resonance imaging (MRI or NMR scan).
- Ultrasound scan.