Melanoma
Melanoma is a type of skin cancer that develops in the skin cells called melanocytes and usually occurs on the parts of the body that have been overexposed to the sun. Rare melanomas can occur inside the eye (ocular melanoma) or in parts of the skin or body that have never been exposed to the sun such as the palms of the hands, the soles of the feet or under the nails.
Often melanoma has no symptoms, however, the first sign is generally a change in an existing mole or the appearance of a new spot. These changes can include:
colour – a mole may change in colour, have different colour shades or become blotchy
size – a mole may appear to get bigger
shape – a mole may have an irregular shape, may increase in height or not be symmetrical
elevation – the mole may develop a raised area
itching or bleeding.
Other symptoms include dark areas under nails or on membranes lining the mouth, vagina or anus.
New moles and spots will appear and change during childhood, adolescence and during pregnancy and this is normal. However, adults who develop new spots or moles should have them examined by their doctor.
Causes of Melanoma
Melanoma risk increases with exposure to UV radiation from the sun or other sources such as solariums, particularly with episodes of sunburn (especially during childhood).
Melanoma risk is increased for people who have:
unprotected UV radiation exposure
a history of childhood tanning and sunburn
a pattern of short, intense periods of exposure to UV radiation
having a lot of moles (naevi) – more than 50 on the body and more than 10 above the elbows on the arms
increased numbers of unusual moles (dysplastic naevi)
depressed immune systems
a family history of melanoma in a first degree relative
fair skin, a tendency to burn rather than tan, freckles, light eye colour (blue or green), light or red hair colour
had a previous melanoma or non-melanoma skin cancer.
Diagnostics of Disease
Melanoma can vary in the way it looks. The first sign is usually a new spot or change in an existing mole.
Physical examination
If you do notice any changes to your skin, your doctor will examine you and carefully check any spots you have identified as changed. Your doctor will use a handheld magnifying instrument (dermascope) and consider the criteria known as “ABCDE”. Further tests may be carried out by your GP or you may be referred to a specialist (dermatologist).
- A – Asymmetry, irregular
- B – Border (uneven or scalloped edges)
- C – Colour (differing shades and colour patches)
- D – Diameter (usually over 6mm)
- E – Evolving (changing and growing).
Biopsy
If the doctor suspects that a spot on your skin could be melanoma, an excision biopsy is carried out with the removal of the whole spot. This will then be examined under a microscope by a specialist to see if there are any cancer cells.
Checking lymph nodes
Your doctor may feel the lymph nodes near the melanoma to see if they are enlarged as melanoma can sometimes travel via the lymph vessels to other parts of your body. Your doctor may also recommend a biopsy to take a sample of the cells from an enlarged lymph node for further examination under a microscope.
If the doctor suspects melanoma, a biopsy may be carried out.
Treatment of Melanoma
Staging
Test results will show whether you have melanoma and if it has spread to other parts of the body. The melanoma will be given a stage of 0-4, usually written in Roman numerals. The most important feature of a melanoma in predicting its outcome is its thickness.
- stage 0 is less than 0.1mm
- stage I less than 2mm
- stage II greater than 2mm
- stage III spread to lymph nodes and stage IV spread to distant skin and/or other parts of the body.
The presence of ulceration also predicts a poor outcome. If distant spread is suspected, CT scans of the chest, abdomen and pelvis are performed. The blood test LDH can sometimes be useful to assess metastatic disease.
Early-stage melanoma
Surgery (wide local excision) can be curative for thin melanomas and requires that the melanoma be removed as well as more normal-looking skin around the melanoma (usually between 5mm and 10mm).
Many people with early melanoma don’t need to have lymph nodes removed. However, in some cases, you may have a sentinel lymph node biopsy which removes the first lymph node the melanoma may have spread to.
The removal of the lymph nodes can cause side effects such as swelling in your neck, armpit or groin. This is called lymphoedema.
If there is a risk that the melanoma could come back, you may be offered additional treatments. These can include immunotherapy and targeted therapy.
Advanced melanoma
Treatment for advanced melanoma, where the cancer has spread to lymph nodes, internal organs or bones, may include surgery, radiation therapy targeted therapy or immunotherapy.
Surgery may be used to treat metastatic melanoma that involves other parts of the skin. Surgery may also still be possible if the melanoma has spread to other organs but will depend on the part of the body that is affected.
Radiation therapy may be of benefit in treating some forms of melanoma. It may be used:
- when cancer has spread to the lymph nodes
- after surgery to prevent the cancer returning
- in combination with other treatments
- as palliative treatment.
Targeted therapy drugs attack specific genetic changes (mutations) that allow melanomas to grow and spread while minimising harm to healthy cells. It is most commonly used for melanomas that have spread to other organs or if it has come back after treatment.
Immunotherapy uses drugs to stimulate the body’s immune system in order to recognise and fight melanoma cancer cells. Ipilimumab, nivolumab and pembrolizumab are three immunotherapy drugs approved for treatment of advanced melanoma.
