Blood test to detect early-stage melanoma developed
Melanoma, the most common type of skin cancer, is traditionally detected via observing changes in irregular moles, and then conducting a skin biopsy for full confirmation. A team from Edith Cowan University in Australia has now developed a blood test that can detect melanoma in its early stages, reducing the need for expensive, and frequently unnecessary biopsies.
In sun-drenched countries like Australia melanoma is a major health problem. While only mildly common in the United States, in Australia melanoma is the third most diagnosed form of cancer. Survival rates are relatively high if it is diagnosed early, but that early detection often relies on vigilant observation of skin irregularities, and then uncomfortable and invasive biopsies. Three out of four biopsies return negative results, making the need for more accurate early diagnostic tools vital in easing the load of these frequently unnecessary procedures on both patients and the health system in general.
In recent years, there have been a number of innovative diagnostic tools developed to detect the dangers of unusual skin moles or spots. A fascinating device called the sKan, which uses heat maps to identify melanoma-related irregularities on the skin, won the international James Dyson Award last year, and researchers at Stanford have also been working on a detection system that uses your smartphone to classify irregular skin spots.
Adding to the arsenal of new diagnostic tools is this new blood test that can accurately pick up early-stage melanoma. The research began by honing down a list of 1,627 different antibodies possibly associated with the condition, and eventually landed on a combination of 10 that most reliably indicated the presence of melanoma.
In initial clinical tests the researchers were able to successfully identify the presence of melanomas in 79 percent of patients that had been previously identified with early-stage melanoma. These results are impressive but possibly a little lower than one would want if completely relying on it as a singular diagnostic tool.
Rodney Sinclair, a dermatologist from the University of Melbourne who did not work on this new research, suggests at this stage the test still needs to be incorporated into a broader array of diagnostic tools as its error rates are a little too high to be relied upon.
"A sensitivity of 79 per cent means that it will detect melanoma in 79 per cent of affected people but miss it in 21 per cent," says Sinclair. "The specificity of 84 per cent means that when the test is positive, 84 per cent of patients will have a melanoma, but 16 per cent won't. The false positive and false negative rates of this test mean that the results will need to be interpreted with caution."
Mel Ziman, head professor at Edith Cowan University's Melanoma Research Group is realistic about further work being needed before this blood test becomes a pragmatic clinical tool. A larger clinical trial is being organized to better evaluate the test's accuracy, and Ziman estimates it will be at least three to five years before the test reaches the hands of doctors.
"The ultimate goal is for this blood test to be used to provide greater diagnostic certainty prior to biopsy and for routine screening of people who are at a higher risk of melanoma, such as those with a large number of moles or those with pale skin or a family history of the disease," says Ziman.
The study was published in the journal Oncotarget.
Source: Edith Cowan University