As melanoma spreads, chances of survival decline. But it has been extremely difficult to detect the tumor cells responsible. Now, Australian researchers feel they know why.
Although melanoma accounts for only around 1 percent of skin cancers, it is responsible for a significant number of deaths.
The American Cancer Society (ACS) predicts that by 2020 more than 100,000 people will be diagnosed with melanoma, resulting in about 7,000 deaths.
There are several reasons why a person can develop melanoma but the sun is responsible for most cases, according to the Skin Cancer Foundation. Notwithstanding this awareness in recent decades rates of this type of cancer have been growing.
A research team at Australia’s Edith Cowan University in Perth has been looking for better ways to diagnose and treat melanoma, recognizing the correlation between early detection and a 99 percent 5-year survival rate.
Their results are published in British Cancer Journal.
The first blood test
Back in 2018, Melanoma Research Group at the university announced the creation of the first blood test for melanoma.
Existing disease detection methods include a visual inspection and biopsies but these come with problems.
At the time, lead researcher Pauline Zaenker explained: “While clinicians do a fantastic job with the available tools, relying on biopsies alone can be problematic.” They’re not only costly and intrusive, but they can also be unreliable.
Initial studies found that the blood test could detect 79 percent of cases of early-stage melanoma.
This spotts body-made autoantibodies as soon as the cancer grows, and is currently undergoing a clinical trial.
“We envisage[ the trial] taking about three years,” said Head Prof. Mel Ziman, adding: “If this is successful, we’d hope to have a study ready for use in pathology clinics soon afterwards.”
Halting the spread
Yet the same research group has found an effective way to track and potentially treat melanoma growth.
Designed in conjunction with the Harvard Medical School in Boston, MA, and physicians from other Australian hospitals, it operates by focussing on circulating tumor cells (CTCs) — the cells that can spread cancer.
“As CTCs shed from the primary tumor and migrate through the blood to form secondary tumors (metastases) in other organs, cancer spreads around the body,” explains lead researcher and associate Prof. Elin Gray.
In melanoma cases, however, detecting these cells isn’t always easy. Detection rates can vary between as low as 40% and as high as 87%.
“If we can find a way to reliably detect these cells, then with a strong diagnostic tool and potentially possibilities for potential treatments, we have the chance to stop melanoma in its tracks,” says Prof. Gray.
Elusive cancer cells
Work by the team explains why CTCs with melanoma have been so enigmatic.
“We now realize that a single-size-fits-all solution can not overcome CTC identification,” says Prof. Gray.
“The structure and bioactivity of these CTCs contains a huge amount of variation, and so they all look different and respond differently to assay tests.
” The melanoma CTCs are hidden within thousands of other cells and matter in the blood to confuse matters more.
“Within one milliliter of blood, from a billion red cells and one million white blood cells, there are often less than 10 cancer cells.” She says that “it is much like finding a needle in a haystack.”
Utilizing artificial intelligence
This level of complexity meant the team used three different tests, instead of just one, to assess melanoma CTCs.
Using this approach on 43 blood samples from people with metastatic melanoma, researchers succeeded in increasing CTC detection rates to 72 percent, which, according to Prof. Gray, “was a substantially and reliably higher result than using a single test.”
The results are only “a first step towards a new way of preventing melanoma from spreading around the body,” says Prof. Gray. But nonetheless, they are a step forward.
The researchers did not finish their work though. Prof. Gray says that they are now working to change the experiments “to include a better combination to reach the widest range of CTCs.”
To improve this process, they are teaming up with experts in artificial intelligence.
Only time will tell if those detection rates will keep rising.