Everything you need to know about malignant melanoma, including risks, warning signs and prevention advice.
Medically reviewed by Dr Juliet McGrattan (MBChB)
Skin cancer is the most common form of cancer in the UK. Each year, between 9 and 12 thousand people in the UK develop a new case of skin cancer or malignant melanoma. Sun radiation is one of the most prevalent contributing factors, so if you’re heading for sunnier climes anytime soon, practising sun safety is vital.
But what exactly is skin cancer? We look at the causes, warning signs and explain how to minimise your risk:
What is skin cancer?
There are two main types of skin cancer:
- Malignant melanoma– cancer in moles.
- The non-melanoma group– basal cell and squamous cell carcinoma.
Malignant melanoma is a type of skin cancer that begins in the skin’s ‘pigmentation system’, ie the skin layer that becomes tanned in the summer.
Melanomas usually start in moles or in areas of normal-looking skin. In rare cases the tumour may begin in the eyes, the respiratory passage, the intestine or the brain. Malignant melanoma is a very dangerous type of cancer, and the patient’s chances of survival often depend on early discovery and treatment.
What causes skin cancer?
Sun radiation is a contributing factor in 90 per cent of all cases of skin cancer. People of all ages can get skin cancer, but it is rarely seen in children. People who are exposed to large quantities of sun radiation can develop skin cancer as early as 20-years-old, but the disease is much more common in elderly people.
Skin cancer is caused by exposure to sunlight and 80% of cases are therefore preventable.
Skin cancer is caused by exposure to sunlight, particularly the ultraviolet (UV) rays, and 80 per cent of cases are therefore preventable. The risk of developing skin cancer is increased following episodes of sunburn, although the there may be a delay of many years before the cancer appears.
A small number of cases are caused by hereditary conditions, but they are also triggered by exposure to sun rays. Sun beds can also cause skin cancer.
Skin cancer warning signs
The below changes to your skin don’t necessarily mean you have skin cancer, but they are red flags so should always be checked out:
- Mole changes
An existing mole changes in colour or shape, or begins to bleed or ooze. Sores that heal very slowly may appear on the mole.
- Mole shape
Moles that have become unusually large or raised above the skin or more than one colour.
- Blood blisters
Especially under toenails, that are not the result of a blow.
- New moles
The appearance of a new irregular mole (it is quite normal for people to develop new moles from time to time until they reach their 40s. There is no need to worry unless the colour of the new mole is uneven, or its edges are ragged). If you are in any doubt, ask your GP to check.
- Unusual blemishes
Any unusual sore, lump or blemish lasting more than a few weeks.
- Unusual skin changes
Areas of skin that become scaly, itchy, tender or red, or areas that ooze, bleed or become crusty.
Skin cancer common symptoms
The symptoms of skin cancer are mostly external, visible factors, making it vital to always check your moles. The signs to look out for include the following:
- The colour of the tumours vary from brown or black to blue or orange.
- The tumours are characterised by having ragged edges and uneven colours.
- Off-shots, sores, crusts, and reddening may be seen in the area surrounding the mole.
- The tumour may resemble a ‘blood blister’ under a nail.
- The mole may itch.
- Moles can be found anywhere on the body, but are typically located on the back, the shoulders, or the back of the legs.
Reduce your risk of skin cancer
While there are no guarantees, there are a number of ways to protect yourself from UV rays and reduce your risk of skin cancer:
✔️ Avoid excessive exposure to the sun, especially the midday sun (from 11am to 2pm).
✔️ Move into the shade and have a siesta (nap!) during the hottest hours of the day.
✔️ Clothing and sun hats can protect the skin from the harmful rays. It’s especially important to cover the skin from 11am to 2pm.
✔️ Children must be protected from sunburn at all times.
✔️ Consult your doctor if you have sores that will not heal or unusual changes in a mole.
Skin cancer diagnosis
Skin cancer can be difficult to recognise, so a biopsy is usually performed. The tissue is then examined under a microscope.
Some GPs can perform the biopsy in the surgery, but it’s usually performed by a dermatologist or a plastic surgeon. The doctor will also look for signs indicating that the cancer has spread to the surrounding tissue or lymph nodes.
Skin cancer treatment
Surgery is the standard treatment for mole cancer. The extent of the procedure is determined by the thickness of the tumour, ie how deeply it has invaded the skin.
It is necessary to remove not only the tumour, but also some of the normal skin around it, and the fatty tissue beneath. If there are signs that the cancer has spread to nearby lymph nodes, these will also be removed, if it is technically possible.
Chemotherapy and radiotherapy may also be used. These treatments are carried out by specialists in a hospital. Newer treatments, using biological therapies, which affect the way the body’s immune system responds to disease, are used to control the melanoma, but cannot cure it. Some can only be used for specific genetic types of melanoma. Melanoma vaccines are still in the research stage and only available as part of a clinical trial.