Melanoma (Skin Cancer)

Melanoma is a type of skin cancer that starts in melanocytes, the cells that give skin its color. It is less common than other skin cancers but more serious, because it is more likely to grow and spread to other parts of the body if it is not found and treated early.

Melanoma can develop anywhere on the skin, including areas not usually exposed to the sun, and more rarely in the eye or other sites. It most often appears as a new mole or a change in a mole you already have.

Non-melanoma skin cancers, such as basal cell and squamous cell carcinoma, are far more common and usually grow slowly and rarely spread. Melanoma is less common but more dangerous because it can spread. This is why any suspicious mole or skin change should be checked promptly — catching melanoma early makes a big difference.

The most common sign is a new mole or a change in an existing one. A helpful guide is ABCDE: Asymmetry (the two halves do not match), Border (irregular or blurred edges), Color (more than one color or uneven color), Diameter (larger than about 6 mm), and Evolving (changing in size, shape, or color over time).

Other signs include a mole that itches, bleeds, becomes crusty, or looks inflamed, or a new mark on the skin that does not go away. Any of these should be checked by a doctor.

The main cause is ultraviolet (UV) light, from the sun and from sunbeds. Episodes of sunburn, especially in childhood, increase the risk. Risk is higher for people with pale skin that burns easily, lots of moles or freckles, red or fair hair, a family or personal history of skin cancer, or a weakened immune system.

Anyone can develop melanoma, but these factors raise the risk. Protecting the skin from UV and being aware of changes to your skin are the most useful steps.

A doctor examines the suspicious mole or skin change, often using a special magnifier (a dermatoscope) to look at it closely. If melanoma is suspected, the area is usually removed and examined under a microscope (a biopsy) to confirm the diagnosis.

If melanoma is confirmed, further tests or scans may be arranged to check the thickness of the melanoma and whether it has spread, which guides treatment. The thickness of the melanoma at diagnosis is one of the most important factors in the outlook.

The main treatment for early melanoma is surgery to remove it, along with a margin of healthy skin around it. For most people whose melanoma is found early, this surgery alone is curative. Nearby lymph nodes are sometimes checked or removed if there is a risk the cancer has spread.

For melanoma that has spread or is at higher risk of returning, newer drug treatments have greatly improved outcomes. These include immunotherapy, which helps the immune system attack the cancer, and targeted therapy, which acts on specific changes in melanoma cells. Radiotherapy is used in certain situations. A specialist team plans the right combination for each person.

The outlook depends mainly on how early the melanoma is found. When it is caught early and is still thin, it is usually cured by surgery and the outlook is very good. More advanced melanoma is harder to treat, though modern immunotherapy and targeted therapy have improved results considerably.

Much melanoma is preventable by protecting the skin from UV: avoiding sunburn, seeking shade, covering up, using sunscreen, and not using sunbeds. Checking your own skin regularly and getting new or changing moles looked at promptly helps find any melanoma at the earliest, most treatable stage.