Seven factors have the greatest predictive value for melanoma risk in people aged over 40
It is recommended that GPs identify patients who are at high risk of developing melanoma, but there has never been a clear definition of who is at high risk.
Researchers at the QIMR Berghofer Medical Research Institute aimed to fill that gap by launching an online melanoma risk assessment tool for people aged 40 and older.
The tool calculates a patient’s risk of developing melanoma over the next three and a half years based on seven factors, including age, sex, skin tanning, moles and natural hair colour at age 21, number of destroyed (burnt or frozen) skin lesions, and sunscreen use in the past year.
The tool is based on a prospective study of nearly 42,000 Queenslanders aged over 40, who were selected at random from the electoral role and followed up over the next
40 months.
“This tool was derived form a very large cohort, which makes it particularly robust,” Professor David Whiteman, who led the research team, said.
The study, published in the Journal of the National Cancer Institute, examined almost 30 potential predictors for melanoma risk, which included factors such as hat use, eye colour and freckles.
The researchers whittled this back to 12 factors that were shown to be significantly tied to melanoma risk, and then settled on seven factors that had the greatest predictive value.
“After all that work, it boiled down to seven items that comprise an algorithm,” Professor Whiteman said.
The tool was shown to be around 69% accurate in an independent cohort.
The tool, which can be found at www.qimrberghofer.edu.au/melanomariskpredictor tells people their melanoma risk relative to people of the same age and gender.
The website also provides tailored health advice about how to manage the risk, such as having routine check-ups.
If high-risk patients were seen regularly by a GP they would have thinner melanomas and a greater chance of survival, Professor Whiteman said.
The study also asked patients about their perceived risk of melanoma, which showed that self-assessment was no better at predicting risk than tossing a coin.
“We found that people’s actual risk of melanoma was quite different to their own assessment,” Professor Whiteman said. “This highlights the importance of getting personalised advice on your melanoma risk, because it could well be different to your perceived risk.”
Gaining a below-average risk rating for melanoma did not mean that people could do away with primary prevention, however.
“All Australians who have European ancestry and fair skin are at higher than average international risk of melanoma,” Professor Whiteman said.
