What Is Melanoma?

Melanoma is a cancer arising from melanocytes, the pigment-producing cells of the skin. It is far less common than basal cell or squamous cell carcinoma, but is the most dangerous common skin cancer because of its potential to spread to lymph nodes and other organs if not caught and treated early. The good news is that when detected at an early stage, melanoma is highly treatable with surgery alone.

Causes & Risk Factors

Intense, intermittent UV exposure and a history of sunburn, particularly in childhood
Fair skin, red or fair hair, and skin that burns easily
A large number of moles, or atypical (dysplastic) moles
A personal or family history of melanoma
Immunosuppression

Signs to Look For

The widely used ABCDE guide highlights features that should prompt assessment of a mole or pigmented lesion:

Asymmetry — one half unlike the other
Border — irregular, notched or blurred edges
Colour — uneven, with shades of brown, black, red, white or blue
Diameter — greater than 6mm (though melanoma can be smaller)
Evolving — any change in size, shape, colour, or new symptoms such as itching or bleeding

In the UK, the weighted 7-point checklist is also widely used clinically: major features (each scoring 2 points) are change in size, irregular shape and irregular colour; minor features (each scoring 1 point) are a diameter of 7mm or more, inflammation, oozing or crusting, and change in sensation. A total score of 3 or more warrants urgent referral.

NICE Referral Pathway

Under NICE guideline NG12, any lesion suspicious for melanoma — based on the weighted 7-point checklist or dermoscopic features — should be referred urgently on the 2-week-wait pathway for prompt specialist assessment.

Diagnosis

Where melanoma is suspected, the standard approach is complete excision biopsy of the lesion with a narrow margin (rather than a partial or shave biopsy), so the entire lesion can be examined by a specialist pathologist. The key prognostic measurement is Breslow thickness — how deeply the melanoma has invaded the skin — which determines both the further surgical margin required and whether further staging investigations are needed.

Treatment

Wide local excision — once melanoma is confirmed, the area is re-excised with a further margin of healthy skin based on Breslow thickness (typically 5mm for melanoma in situ, 1cm for thickness up to 1mm, 1–2cm for 1–2mm, and 2cm for thicker melanomas)
Sentinel lymph node biopsy — considered for melanomas with a Breslow thickness over 0.8mm, or other higher-risk features, to check whether the cancer has spread to the nearest lymph node basin
Reconstruction — depending on the site and size of the defect after wide excision, closure may be direct, or require a skin graft or local flap
Adjuvant therapy — for higher-stage or node-positive melanoma, further treatment such as immunotherapy or targeted therapy is coordinated through the skin cancer multidisciplinary team (MDT) and oncology

Follow-Up & Self-Examination

Regular follow-up after treatment is tailored to the stage of melanoma. Patients are also taught simple skin self-examination, since a personal history of melanoma increases the chance of developing a further melanoma elsewhere.

Melanoma