One day in the future, doctors may be able to locate and kill cancer cells with a non-invasive laser.
In a paper published in Science Transitional Medicine last week, scientists from the University of Arkansas Medical Sciences discussed the performance of their laser device (the cytophone), boasting a 96 percent success rate and a sensitivity 1,000 times higher than current technology.
The American Academy of Dermatology (AAD) predicts 192,310 Americans will be diagnosed with melanoma this year, with Caucasians and men over 50 being the most at risk.
As the study authors highlight, one of the scariest things about melanoma is its ability to metastasize (i.e. spread from its original source to other parts of the body) early on in the disease progression. Once it's metastasized to distant organs, the average 5-year survival rate plummets, from 97 percent (or higher) during very early, nonmetastatic disease to 10 to 15 percent.
The key is to catch the cancer before it gets a chance to spread. This can involve targeting circulating tumor cells (CTCs) shed by the primary tumor in the blood, which is where the cytophone comes in.
The device picks up passing melanoma cells circulating in near-surface blood vessels, which heat up slightly due to their darker coloring. This heating triggers a small acoustic wave that is then detected by the cytophone's ultrasound detector. Impressively, the study authors say, it can identify a solitary CTC in a liter of blood.
It's a big claim, but the results of the study are promising. When the cytophone was tested on 28 melanoma patients and 19 healthy controls, it picked up spikes of CTC activity in 27 (96 percent) of melanoma patients and none of the controls.
But that's not all. The device doesn't stop at detecting CTCs – it appears to be able to destroy them, too. When the researchers turned up the scale on the laser (to still safe levels), the results reveal lower levels of CTCs after an hour-long treatment, which would imply it had a hand at killing at least some of the cancer cells.
It might not be enough to wipe out the tumor altogether, but it could be used alongside other treatments to boost performance, lead author Vladimir Zharov suggests. Likewise, the device could be used to track the effectiveness of anti-cancer drugs, check for signs of melanoma post-treatment, or take on a preventative role similar to mammograms.
But we might not want to get too ahead of ourselves just yet. "It’s fascinating that it’s possible to detect these circulating tumor cells literally through the skin," Klaus Pantel, a medical oncologist from the University Medical Center Hamburg-Eppendorf, Germany, told Science. But he and others warn that much more research waits to be done before it can have real-life applications. That includes checking its effectiveness in patients with darker skin as higher melanin levels in healthy cells could make it harder to detect CTCs. Additionally, just three patients with early-stage melanoma were tested in the study, a number that will need to be increased substantially in subsequent trials.