Prevention & Surveillance

1. Why Melanoma Prevention Works

Cutaneous melanoma is one of the few common cancers in which a single modifiable behavioural exposure (UV) is responsible for a majority of cases. Modeling estimates from Australia (Olsen et al., JNCI 2014) attribute ~63–76% of melanomas to UV exposure — a population attributable fraction comparable only to lung cancer and tobacco. Yet, unlike tobacco, UV exposure has both beneficial (vitamin D, mood) and obligate (outdoor occupation) components, making the public- health task more nuanced.

Three lines of evidence support that prevention actually works at the population level:

• Australian melanoma incidence in adults <40 began to decline in the 2010s following 30+ years of SunSmart programmes — the first downward incidence inflection in any high-incidence country.
• Tanning-bed bans (Brazil, Australia) and under-18 tanning-bed restrictions (UK, much of EU/US) followed the 2009 IARC reclassification.
• The Nambour randomised trial (Green et al., JCO 2011) showed daily sunscreen use halved invasive melanoma incidence over 10-year follow-up.

2. The Sun-Protection Hierarchy

Public-health messaging emphasises a hierarchy of protective behaviours, approximately in order of effectiveness:

Behavioural interventions (clothing, shade, timing) are typically more effective than chemical interventions (sunscreen) because compliance is more reliable. Sunscreen is best as the last layer of protection on otherwise-unavoidably exposed skin (face, hands).

3. SPF, Broad-Spectrum, UPF

Sun protection factor (SPF): the ratio of UV dose required to produce minimal erythema on sunscreen-protected skin to that on unprotected skin, measured against UVB. Approximate UVB transmission:

• SPF measurement assumes 2 mg/cm² application; real-world application is typically 0.5–1.0 mg/cm², roughly halving effective SPF.
• “Broad spectrum” sunscreens cover both UVB and UVA. UVA protection is reflected in PA+/++/+++/++++ ratings (Japan) or boots-star (UK).
• Active ingredients: organic (avobenzone, octocrylene, ecamsule, bemotrizinol, tinosorb) and inorganic (zinc oxide, titanium dioxide, with the latter two providing the broadest UVA cover).
• Re-application every 2 hours, after swimming, and after toweling is essential.

UPF (ultraviolet protection factor): the analogous rating for fabric and clothing. UPF 50+ tightly-woven fabric blocks ~98% of UV. Wet, light-weight, or stretched fabrics offer much less protection. Sun-protective clothing is the most reliably effective protection per unit body area.

4. SunSmart & Population-Level Programs

Australia’s SunSmart program (Cancer Council Victoria, est. 1988, building on the “Slip!Slop!Slap!” campaign of 1981) is the longest-running and best-evaluated melanoma-prevention programme in the world. It combined:

• Mass-media campaigns (television, billboard) over decades.
• School-based education and shade-provision in every Australian primary school.
• Workplace policies (outdoor-worker UV-protection regulations).
• Real-time UV index reporting in weather forecasts.
• Tax-deductible status for sun-protective clothing.
• Subsidised sunscreen at workplaces and schools.

Cost-effectiveness analyses (Shih et al., Cancer Epidemiol Biomarkers Prev 2009) estimate SunSmart at ~AUD$3.85 return per dollar invested over 30 years — a figure that rises with the incidence-curve flattening evident from ~2010.

Internationally, SunSmart has been adapted by Canada (1995), New Zealand (1997), the UK (2006), and selectively in northern European countries. The US has lagged in coordinated national melanoma-prevention campaigns, partly because of federated public-health structure and lobbying by the indoor-tanning industry; under-18 tanning-bed bans now exist in most US states but federal action has been piecemeal.

5. Screening & Skin Self-Examination

Whether whole-body skin examination (WBSE) should be offered as population-based melanoma screening is unsettled. The evidence:

• The German SCREEN trial (Schleswig-Holstein, 2003–2004): a population-based opt-in screening saw a ~50% drop in melanoma mortality in the screened region over 5 years vs neighbouring regions — but the effect was not durable when the program was discontinued, suggesting confounding by detection of indolent disease.
• USPSTF (US Preventive Services Task Force) 2023 update: insufficient evidence to recommend for or against routine WBSE for asymptomatic adults (“I” statement).
• No randomised controlled trial of population-wide WBSE has been completed.
• Targeted screening of high-risk individuals (CDKN2A, >100 nevi, prior melanoma) is universally recommended.

Skin self-examination — monthly, with the help of a partner for the back — is easy, free, and supported by observational evidence: people who self-examine present with thinner melanomas and have better long-term mortality. The recommendation is universal but has not been tested in an RCT.

Total-body photography (sometimes paired with sequential dermoscopic imaging) is the standard for high-risk patients with many nevi: it allows the dermatologist to spot a new or evolving lesion against the patient’s baseline pigmentation pattern.

6. Surveillance after Melanoma Diagnosis

Post-diagnosis surveillance has two purposes: detecting recurrence (in the scar, regional nodes, or distant) and detecting second primaries(lifetime risk ~5–10% in melanoma survivors).

Patient-reported symptoms remain the most common trigger of recurrence detection even in protocol-driven surveillance. Brain imaging is increasingly emphasised given that intracranial relapse is a particular pattern of melanoma and that modern combination immunotherapy can produce intracranial responses.

7. Pediatric & Pregnancy Melanoma

Pediatric melanoma is rare (~7 cases per million per year) but carries unique features:

• ~25% arise within or adjacent to a giant congenital melanocytic nevus (>20 cm projected adult diameter).
• Spitzoid morphology more common — histologically challenging to distinguish from atypical Spitz tumour.
• BRAF V600E less common than in adult melanoma; CDKN2A loss, kinase fusions (e.g. NTRK rearrangements) more common — potentially actionable with targeted therapy.
• Children often fail ABCDE: pediatric melanoma is more often amelanotic, symmetric, and uniformly coloured than adult disease. The CUP / E mnemonic was proposed: Colour uniformity / Variable bumps; Amelanotic; Bleeding/Bumping; Colour uniformity; De novo / Diameter; Evolution.
• Outcomes are often slightly better than adult equivalents stage-for-stage.

Melanoma in pregnancy is the commonest cancer diagnosed during pregnancy after breast and cervical:

• Stage-for-stage outcomes appear similar to non-pregnant counterparts in most modern series.
• The placenta is the only site of fetal metastasis — rare but reported. After delivery the placenta and cord must be sent for histology if mother has known melanoma.
• WLE under local anaesthesia is safe in any trimester. SLN biopsy: technetium safe; isosulfan blue dye traditionally avoided.
• Targeted therapy (BRAF/MEK inhibitors) and immunotherapy (anti-PD-1, anti-CTLA-4) are generally avoided during pregnancy, with emergency exceptions.
• The historical concern that pregnancy worsens prognosis has not been borne out in modern matched-cohort analyses.

8. Liquid Biopsy & ctDNA Monitoring

Circulating tumour DNA (ctDNA) is fragmented (~166 bp) DNA released by apoptotic tumour cells into plasma. Detection by digital droplet PCR for known driver mutations (e.g. BRAF V600) or by next-generation sequencing of personalised tumour-informed panels:

• Recurrence prediction: post-resection ctDNA in stage III predicts recurrence with ~80% sensitivity and 100% specificity ahead of imaging by ~2–9 months (Lee et al., JCO 2018; Tan et al., Ann Oncol 2019).
• Therapeutic monitoring: rapid ctDNA decline within 4–8 weeks of starting BRAF+MEK or anti-PD-1 predicts long-term response; persistent or rising ctDNA flags resistance early.
• Pseudoprogression: when imaging shows growth but ctDNA is falling, the lesion is likely immune-infiltrate rather than tumour growth — supports continuing immunotherapy.
• Resistance mutation detection: emerging NRAS Q61 in a BRAF-mutant patient on BRAF+MEK can be detected in plasma months before clinical progression.

Trials are now ongoing of ctDNA-adapted adjuvant strategies: continue or escalate adjuvant therapy in ctDNA-positive patients, de-escalate or stop in ctDNA-negative. This is one of the most active fronts in melanoma clinical research.

9. The Frontier — Where Melanoma Goes Next

The 2025–2030 horizon for melanoma:

• Personalised mRNA neoantigen vaccines. The mRNA-4157/V940 trial (KEYNOTE-942, Weber et al., Lancet 2024) showed that adjuvant mRNA neoantigen vaccine + pembrolizumab reduced recurrence/death by 44% vs pembrolizumab alone in resected stage III/IV. Phase 3 is underway.
• First-line and earlier-line TIL therapy. SPECTRUM-D / TILVANCE will determine whether lifileucel + anti-PD-1 outperforms anti-PD-1 alone in untreated stage IV.
• Bispecific T-cell engagers. Building on the success of tebentafusp in uveal melanoma; next-generation BiTEs in cutaneous melanoma in development.
• Pan-RAF and second-generation inhibitors — targeting NRAS-mutant and class II/III BRAF mutants.
• ctDNA-driven adjuvant escalation — treating molecular relapse before clinical relapse.
• Public-health prevention 2.0 — AI-augmented home dermoscopy, smartphone-based skin-monitoring, real-time UV-index integration with consumer wearables.

The combination of these axes — molecular targeting, immune-based therapeutics, real-time monitoring, and population-level UV-exposure reduction — mean melanoma is the single best example in oncology of how biology-informed prevention, diagnosis, and treatment can collectively change a cancer’s trajectory within a generation.