Melanoma (Skin Cancer)
Melanoma is a malignant neoplasm of melanocytes—the pigment-forming cells in the skin, mucosa, and eye. Although it represents barely 1 % of all cutaneous cancers, it accounts for the majority of skin-cancer deaths because it metastasizes early via lymphatic and haematogenous routes. The American Cancer Society projects ≈105 000 new invasive melanomas and 8 400 deaths in the United States in 2025, while SEER data place the lifetime risk at about 1 in 46 for men and 1 in 64 for women.
Symptoms
Early melanoma is often asymptomatic and discovered as a changing mole. Warning signs follow the ABCDE mnemonic: Asymmetry, Border irregularity, Colour variegation, Diameter > 6 mm, and Evolving size, shape, or symptoms. Nodular melanoma may present as a rapidly enlarging dark-brown to black papule that bleeds easily. Acral lentiginous melanoma appears as an irregular pigmented patch on palms, soles, or beneath nails, while amelanotic variants may resemble a pink papule mistaken for eczema or basal-cell carcinoma.
Risk Factors
Intermittent intense sunburns in childhood or adolescence, chronic recreational UV exposure, indoor-tanning device use, fair skin with freckles, red or blond hair, blue or green eyes, numerous or atypical naevi, personal or first-degree family history of melanoma, CDKN2A or CDK4 germ-line variants, and immunosuppression from solid-organ transplant, HIV, or chronic lymphocytic leukaemia all amplify risk. On the population level, 87 % of melanomas in the United Kingdom are attributed to preventable UV exposure.
Diagnosis
Dermoscopic examination highlights chaotic pigment networks and blue-white structures that prompt excisional biopsy with 1–2 mm margins encompassing the entire lesion to permit accurate Breslow thickness measurement. Histopathology classifies subtype, depth, ulceration, and mitotic index. Once melanoma is confirmed, wide local excision margins are guided by thickness (0.5 cm for in-situ, up to 2 cm for tumours > 2 mm). Sentinel-node biopsy is offered for lesions ≥ 0.8 mm or < 0.8 mm with ulceration because nodal status is the strongest prognostic factor. Advanced disease is staged with CT, PET/CT, or brain MRI.
Treatment
Localised melanoma is cured by surgery alone. Adjuvant therapy for stage IIB–III includes anti-PD-1 antibodies (nivolumab or pembrolizumab) or, for resected BRAFV600-mutant stage III, oral BRAF/MEK inhibitors (dabrafenib + trametinib). Version 2.2024 NCCN Guidelines added neoadjuvant nivolumab + ipilimumab for high-risk stage III, reflecting event-free-survival benefit in phase 3 trials. Metastatic melanoma treatment is genotype-directed: first-line PD-1 blockade alone or in combination with CTLA-4 blockade; or combined BRAF/MEK inhibition for BRAFV600 tumours, now frequently sequenced after immunotherapy. Ten-year follow-up of CheckMate 067 shows 34 % overall survival with nivolumab plus ipilimumab versus 21 % with ipilimumab alone, documenting the first plateau in metastatic-solid-tumour survival curves. TVEC oncolytic therapy, IL-2 agonists, adoptive T-cell therapy, and tumour-infiltrating-lymphocyte products expand options for refractory disease.
Outlook
Five-year survival approaches 99 % for stage IA melanoma but falls to 70 % in stage II, 60 % in stage III, and historically below 20 % for stage IV—now improved to > 50 % in selected patients receiving combination immunotherapy. Early detection remains critical: every millimetre increase in Breslow depth halves survival. On population level, mortality has begun to decline in high-income countries owing to screening and effective systemic therapy despite rising incidence.
Complications
Locally advanced melanoma can invade underlying muscle and bone; regional spread causes bulky nodal disease and lymphoedema; distant metastases target lung, liver, brain, and bone, leading to respiratory failure, hepatic insufficiency, pathological fractures, or intracranial hypertension. Immune-related adverse events from checkpoint blockade—colitis, pneumonitis, endocrinopathies—injure multiple organs but are manageable with early corticosteroid intervention.
Prevention
Achieving and sustaining > 95 % two-dose coverage with routine childhood MMR vaccination is vital. Individuals should avoid midday sun (10 am–4 pm), seek shade, never use indoor tanning devices, and apply a full ounce of SPF 30+ sunscreen every two hours when outdoors. Regular skin examinations by a qualified clinician plus self-exams can detect thin melanomas early. Patients treated for melanoma should receive continuous sun-safety education and psychosocial support to maintain behavioural change.
Support
After diagnosis, follow surgical and medical appointments without delay; protect the operative site from sun until healed; use SPF 30+ broad-spectrum sunscreen, UPF clothing, sunglasses, and wide-brimmed hats daily; perform monthly head-to-toe self-exams with a mirror or partner and photograph naevi to track evolution; and attend scheduled dermatology skin checks every 3–12 months depending on stage. Family members of patients with multiple primary melanomas should ask about their own skin screening and, if there is a strong family history, discuss genetic counselling.
Sources
The information presented above is supported by reputable medical sources and research publications. These references provide additional clinical insights and evidence-based findings for healthcare professionals and individuals seeking comprehensive understanding of this medical condition.
