Among skin cancers, melanoma has a dual distinction: it can be difficult to catch early, before it has spread to other parts of the skin or other organs, and it is particularly deadly.
As the number of melanoma cases rise around the world, with approximately 132,000 new cases currently being diagnosed each year, Australia has been hit especially hard. The nation features the world’s second-highest melanoma rate. Each year, the disease kills more than 1,700 people in Australia—more than are killed in traffic accidents—and is diagnosed in thousands of others.
Even with melanoma being discovered in more and more people, physicians and researchers worry that current tools used to detect melanoma are not always optimal.
Melanoma is currently detected by clinicians performing biopsies on moles or suspicious-looking areas of the skin and pathologists then scanning the sample for signs of the disease. This detection method is invasive as it requires the removal of at least one square centimetre of skin from the patient. It is also expensive as the annual cost to the Australian health system of the diagnosis and treatment of melanoma is estimated to be $201 million. What’s more, approximately three out of every four biopsies comes back negative. However, given the dangers associated with melanoma, it is preferable that clinicians err on the side of caution and continue conducting biopsies, notwithstanding the number that come back negative.
For the above reasons, researchers around the world have been in search of a test that could identify melanoma earlier, and with more accuracy.
Now, in a breakthrough that could save thousands of lives, researchers at Edith Cowan University (ECU) have devised a blood test that can detect early-stage melanoma in approximately 80 percent of patients.
The discovery is the result of a scan university researchers conducted on more than 1,600 types of antibodies, with a goal to identify a combination of 10 antibodies that can best indicate the presence of melanoma in blood. The blood test, which is still in the development phase, scans for antibodies the body produces when melanoma first presents itself.
“The body may produce these antibodies as soon as melanoma first develops, which is how we have been able to detect the cancer in its very early stages with this blood test,” says Dr Pauline Zaenker, the lead researcher for ECU’s Melanoma Research Group. “No other type of biomarker appears to be capable of detecting the cancer in blood at these early stages.”
Researchers at ECU analysed the blood of 104 melanoma patients and 105 healthy people, the latter serving as a control group. They found 139 possible antibodies that were expressed at higher levels in patients with melanoma. The research group then used high-level statistical analysis to identify a group of 10 “autoantibodies”—weapons the body utilises to ward off illnesses—and found that they could be used to detect early-stage melanoma in 79 percent of patients.
Such a tool could be of particular value to people who present additional diagnostic difficulties, such as those whose skin contains 100 or more moles or thin early-stage melanomas, as well as those patients at especially high risk of developing the cancer. It also might allow doctors to reach more patients, including those in remote or rural areas.
The blood test is not seeking to replace biopsies, rather to improve the early diagnosis of melanoma and reduce the risk of cases being missed to help improve patient outcomes.
“A positive test would give doctors an additional tool to have more diagnostic certainty prior to a biopsy,” says Mel Ziman, a professor in ECU's School of Medical and Health Sciences, and head of the Melanoma Research Group. “Findings must now be tested among larger groups of patients,” she adds.
The research group is looking to perform a clinical trial with 1,000 participants who have been prescribed a biopsy for melanoma, and from whom blood will be collected. The blood test findings will then be compared to the biopsy results.
“The clinical trial will enable us to identify how accurate our test is. We would like to improve its accuracy to 90 percent, which is what should be expected of diagnostic testing,” says Professor Ziman. “By testing more people, we hope to find the optimal set of antibodies, which will increase the test’s accuracy rate.”
Scientists say the end result of their work—saved lives—is more than worth the price of the investment.
“Patients who have their melanoma detected in its early stage have between a 90 and 99 percent chance of a five-year survival rate whereas if it is not caught early and it spreads around the body, the chance of a five-year survival rate drops to less than 50 percent,” Dr Zaenker says.
She adds: “This is what makes this blood test so exciting as a potential screening tool because it can detect melanoma in its very early stages when it is still treatable.”
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