What is a melanoma?

Melanoma is a malignant tumour that develops when the melanocytes, the cells that produce melanin (the pigment that gives the skin its colour), start to grow uncontrollably. Although melanomas can occur anywhere on the skin, they often develop on areas of skin that are exposed to the sun, such as the face, back, legs and arms. However, melanomas can also occur on less exposed parts of the body, such as the soles of the feet, the palms of the hands and even in the eyes (ocular melanoma).

Melanoma is dangerous because it can spread quickly (metastasise) to other parts of the body, such as the lymph nodes, lungs, liver, brain and bones, which makes treatment more complicated and the prognosis worse. The diagnosis and treatment of melanoma fall under regular specialist medical care and take place in hospital. Early detection and treatment are therefore crucial for improving the chances of survival.

How does melanoma develop?

Melanoma develops through DNA damage in the melanocytes, usually caused by exposure to ultraviolet (UV) radiation from the sun or sunbeds. This DNA damage can lead to mutations in the genes that control cell division, causing the melanocytes to start growing and multiplying uncontrollably. Factors that increase the risk of developing melanoma include:

Excessive exposure to UV radiation: prolonged exposure to sunlight, sunburn and the use of sunbeds.
Fair skin: people with fair skin, blond or red hair, and blue or green eyes are at higher risk.
Family history: a family history of melanoma or other forms of skin cancer increases the risk.
Atypical moles: people with many or atypical (dysplastic) moles are at higher risk.
Personal history of skin cancer: people who have previously had melanoma or another skin cancer are at increased risk of developing new melanomas.

What are the symptoms of melanoma?

Melanoma can appear as a new mole or through changes in an existing mole. The characteristics of a melanoma can vary, but there are some general guidelines that help identify it, known as the ABCDE rule:

A (Asymmetry): one half of the mole does not match the other half; it has an asymmetrical shape.
B (Border): the edge of the mole is uneven, jagged or blurred.
C (Colour): the colour is not uniform and may contain different shades of brown, black, pink, red, white or blue.
D (Diameter): the mole is larger than 6 millimetres (about the size of a pencil eraser), although melanomas can sometimes be smaller.
E (Evolving): the mole changes in size, shape or colour, or shows new symptoms such as bleeding or itching.

Other possible symptoms are:

New skin lesion: a new, unusual-looking spot on the skin.
Sore that does not heal: a sore that keeps bleeding or does not heal.
Change in sensation: a mole that itches, burns, is numb or is tender.

How is melanoma treated?

The treatment of melanoma depends on the stage of the cancer, its size and location, and whether it has spread to other parts of the body. The main treatment options are:

Surgical excision: the primary treatment for melanoma, in which the tumour is removed together with a margin of healthy tissue to ensure that all cancer cells are removed.
Sentinel lymph node biopsy: a procedure that examines whether the melanoma has spread to the nearby lymph nodes. If the cancer has spread, additional lymph nodes may be removed.
Immunotherapy: treatment that stimulates the immune system to fight cancer cells. This can be effective for advanced melanoma.
Targeted therapy: medicines that specifically target mutations that are common in melanoma cells, such as BRAF mutations.
Chemotherapy: traditional cancer treatment that kills cancer cells or slows their growth, although it is less effective for melanoma than for other cancers.
Radiotherapy: used to shrink the tumour or kill cancer cells, especially when surgery is not possible.

Prognosis and prevention

The prognosis for melanoma depends heavily on the stage at which it is detected. Early-stage melanoma has a very good prognosis with a high chance of survival, while advanced stages, in which the cancer has spread, are harder to treat and have a worse prognosis.

Preventive measures include:

Limiting sun exposure: avoiding direct sunlight, especially during peak hours, and using sunscreen with a high SPF.
Regular skin checks: self-examination and regular dermatological check-ups to spot changes in the skin early.
Protective clothing: wearing hats, sunglasses and clothing that covers the skin to reduce exposure to UV radiation.
Avoiding sunbeds: avoid sunbeds, because they can emit significant amounts of harmful UV radiation.

What is the difference between melanoma and other forms of skin cancer?

Melanoma is the most aggressive form of skin cancer and differs from other forms such as basal cell carcinoma and squamous cell carcinoma, which usually remain local and are less likely to spread. Melanoma has a much higher risk of spreading and is responsible for the majority of deaths from skin cancer. Early detection and treatment of melanoma are vital because of the high risk of spread to other parts of the body.

Melanoma is a potentially life-threatening form of skin cancer that requires early recognition and treatment. By taking preventive measures and being alert to changes in the skin, the chance of successful treatment and survival can be significantly improved.

See also our page about Removal of skin imperfections or having a mole removed.