Australia and New Zealand have the highest rates of skin cancer in the world.
Between 12,000 and 14,000 Australians are diagnosed with melanomas - the potentially lethal form of skin cancer - every year, and around 1,500 will die from them.
While people with fair skin and freckles are most at risk, those with dark skin are not immune.
Detecting a melanoma tumour at an early stage can increase a patient's five-year survival rate to as high as 99 per cent, but receiving a diagnosis at a later stage can see this drop to 15 - 20 per cent.
Now, researchers at Edith Cowan University in Western Australia have come up with a blood test to help detect early-stage melanoma.
Head of the university's Melanoma Research Group, Professor Mel Ziman, said the test relies on identifying "autoantibodies".
“Your immune system’s white blood cells produce antibodies to [fight] foreign invading pathogens like bacterial viruses. But they also produce antibodies to [fight] abnormal cancer cells, called autoantibodies,” she said.
“The immune system then amplifies this signal, producing multiple autoantibodies to the cancer cells. These autoantibodies are expressed at very early stages of the cancer, they are easily accessible in the blood, and so it provides a fantastic chance for identifying early cancer."
Blood taken from more than 200 people - half who had melanoma - was tested for 10 "biomarkers" or proteins.
Professor Ziman said in more than 80 per cent of cases, the blood test was able to detect early-stage melanoma.
CEO of the Cancer Council Australia, Professor Sanchia Aranda, is keeping an open mind. She said while she's optimistic about the development of new tests like this one, many questions remain, including its cost-effectiveness and who would take it.
There's also the question of accuracy.
Professor Aranda points out that there are numerous types of biomarkers that can occur, and “not all patients produce exactly the same biomarkers in every situation”.
ABCDE inaccuracy
People normally go to their doctors if they have concerns over moles, who will then examine it according to what's called the "ABCDE" - asymmetry, irregular borders, colour, diameter and if it's evolving or changing.
According to Professor Ziman, diagnosis at an early stage can prove challenging for small or thin melanomas, for people with numerous moles, and colourless melanomas. And she said a blood test can help clear up the "inaccuracy" and differing opinions over whether something needs further attention.
If a clinician suspects a mole may be something more, the next step is a biopsy, where the lesion is cut out of the skin. Negative biopsies cost Australian health authorities more than $70 million every year. But patients whose blood tests are positive will need a follow-up biopsy to confirm the results.
The Cancer Council's Professor Aranda said biopsies are still currently the best method for ensuring a possible cancer is extracted from a patient.
"You have the added advantage that not only is the biopsy taken, the lesion is excised at the same time, and you only need to get more extensive surgery if in fact the cancer’s been found to spread through the tissues surrounding the original lump,” she said.
“If that’s the case then no amount of blood tests could have told you that that was the case, you’ve got to have the lesion excised to do that."
It's expected to be another three years before the test is widely available.
