Quick answer
What is melanoma skin cancer?
Melanoma is the most serious skin cancer — develops from melanocytes often in existing or new moles. Warning signs include asymmetry, irregular borders, colour variation, diameter over 6mm, and evolution (changing). See a GP within 2 weeks for suspicious mole — urgent referral on 2-week wait pathway. Thin melanomas cured by excision; advanced disease treated with immunotherapy (nivolumab, pembrolizumab). Protect skin from sunburn — major preventable risk factor.
Melanoma — the mole that kills if ignored
Melanoma arises from melanocytes — pigment cells — ~16,000 UK cases yearly — rising incidence. It causes most skin cancer deaths despite fewer cases than non-melanoma skin cancers.
Early thin melanoma — >95% 10-year survival — late metastatic — immunotherapy era improved but still serious.
See mole changes symptom guide.
Warning signs — ABCDE + ugly duckling
Asymmetry
Border irregularity
Colour variation
Diameter >6mm (not threshold alone)
Evolution — change — most important
Ugly duckling — mole different from all your others
Amelanotic melanoma — pink/red — delayed diagnosis risk
Acral lentiginous — palms, soles, nails — not sun-related
Risk factors
- sunburn history
- sunbed use
- fair skin, many freckles/moles
- family history melanoma
- immunosuppression
- ** previous melanoma** — 10% get second
Diagnosis
GP dermatoscopy — 7-point checklist, weighted checklist
2-week wait excision biopsy — full thickness — never shave
Histology:
- Breslow thickness — mm depth — prognosis
- ulceration
- mitotic rate
- margins
Staging:
- sentinel lymph node biopsy — Breslow ≥1mm or selected thinner
Treatment by stage
Stage 0 (in situ):
- wide local excision
Stage I–II:
- excision — margins per guidelines (e.g. 1–2cm by depth)
- SLNB informs staging
Stage III:
- lymph node dissection if macroscopic nodes
- adjuvant pembrolizumab/nivolumab — stage III resected
Stage IV:
- immunotherapy — pembrolizumab, nivolumab, ipilimumab+nivo
- BRAF/MEK inhibitors — BRAF V600 mutation
- TIL therapy — specialist
Prevention
- no sunbeds
- SPF 30+, reapply
- shade 11–3
- protect children
Vitamin D — diet/supplement if avoiding sun — do not burn for vitamin D
Melanoma vs basal cell carcinoma
| Melanoma | BCC | |
|---|---|---|
| Pigment | Often dark | Pearly, rolled edge |
| Metastasis | Yes | Rare |
| Urgency | 2WW | 2WW if suspected |
Non-melanoma skin cancers — common, rarely fatal — separate guide if needed.
Changing mole — 2-week GP — excision takes minutes, metastatic melanoma takes lives.
Common questions
- What does melanoma look like?
- Often brown or black patch or lump — may be pink or skin-coloured (amelanotic). Asymmetrical shape, irregular border, multiple colours within one mole, larger than 6mm, or changing size/shape/colour/itch/bleed. Can appear anywhere including soles, nails, and mucosa — not only sun-exposed sites.
- What is the ABCDE rule for moles?
- Asymmetry — halves differ. Border — irregular or blurred. Colour — uneven shades. Diameter — often over 6mm (but small melanomas exist). Evolving — any change most concerning — see GP promptly.
- Is melanoma curable?
- Thin early melanoma — excision with appropriate margins cures most. Sentinel lymph node biopsy guides staging in thicker melanomas. Stage IV — immunotherapy and targeted therapy (BRAF/MEK inhibitors if BRAF mutated) improve survival — not always curable but long remissions possible.
- Does sunburn cause melanoma?
- Intermittent intense UV exposure and sunburn — especially childhood — major risk factor. UV from sunbeds also carcinogenic — illegal for under-18s in UK. Protect with shade, clothing, SPF 30+ broad spectrum, avoid peak sun 11am–3pm.
- Should I worry about every mole?
- Most moles are benign naevi. Worry if changing, looks unlike your other moles, new after age 40, or symptomatic (bleeding, itching persistently). Dermatoscopy by trained GP or dermatologist improves accuracy — avoids unnecessary excisions and catches melanoma early.