Opportunistic screening for melanoma is the status quo in Australia but experts are keen to understand whether targeted risk-based screening would provide more benefits.
The consensus from a 2019 Melanoma Screening Summit was that the rising personal and financial costs of melanoma in the community could possibly be mitigated with a more systematic approach to early detection.
Such an approach could harness new risk-stratification tools and imaging technology augmented by AI algorithms.
However there are gaps in the evidence regarding the “additional benefits, harms and costs of introducing a formal targeted screening program.”
In a report from the Summit, published in the ANZ Journal of Public Health, the researchers said there had been lost opportunities in the past – for example, with a melanoma screening trial in Queensland failing to progress beyond its pilot phase.
“To attempt such a trial now would require a much larger sample, as more background opportunistic screening is occurring now compared to 20 years ago; new targeted and immunotherapies have also led to increases in survival for advanced melanoma making a mortality endpoint more elusive,” they wrote.
“Unless the trial was restricted to people at higher risk of disease, the sample size required to detect a clinically significant difference in mortality may now be too large to be feasible (estimated to range between 82,000 per group if men 50 years or older were targeted to 320,000 if the general population 18 years or older was targeted).”
The researchers, mostly from Queensland, said there was currently insufficient evidence that population screening reduces melanoma mortality. Instead it appears to increase detection of thin and in situ melanomas.
“One reason why it may be difficult to reduce mortality by screening is the difficulty of detecting fast-growing and often fatal melanomas such as those of nodular or amelanotic subtypes. About 15% of all incident melanomas belong to these uncommon subtypes but they are responsible for up to 30% of all deaths.”
The report said the cost-effectiveness of screening for melanoma was also unknown.
“…however, targeting high-risk groups for screening and surveillance appears more cost-effective than an untargeted approach.”
Interestingly, the diagnosis of keratinocyte cancers has been seen as a cost rather than a benefit of screening for melanoma.
“However, the early detection of keratinocyte cancers may lessen the need for or the extent of surgery and prolonged treatment, and these potential benefits need further study.”
The report concluded “…further research is needed to understand how to best optimise melanoma early detection in Australia, particularly in light of emerging technologies and treatments for advanced melanomas that may change the balance of benefits and harms of different screening strategies.”