Detecting melanoma—the most lethal form of skin cancer—still relies on dermatologists eyeballing moles and deciding which ones warrant a biopsy. A new handheld device developed by scientists at the British Columbia Cancer Agency (BCCA) and licensed to Verisante Technology could provide instant information about the molecular makeup of moles.
The device, called the Verisante Aura, is held above a mole, and uses Raman spectroscopy, a technique that distinguishes molecules using their vibrational states, to scan for those whose relative concentrations are characteristic of melanoma. The device returns a verdict within seconds. Following a successful small clinical trial, Verisante is now analyzing the results of another trial with 1,000 moles. The company plans to seek approval from the U.S. Food and Drug Administration later this year.
For patients whose melanoma isn’t caught early, the life expectancy is less than a year. And rates of the disease are skyrocketing: the current estimate is that one in 58 Americans will get melanoma in their lifetime, up from one in 1,500 in 1935.
Work on the new device began in 2000, when dermatologists at BCCA were studying whether certain skin diseases could be identified by their unique spectral characteristics. In Raman spectroscopy, laser light changes the vibrational state of the bonds within molecules, which in turn causes a shift in the light that is reflected back to a sensor. The magnitude and direction of that shift reveal what molecules are in the sample, and at what concentration.
“We thought that because the Raman spectrum shift was a direct reflection of the molecules targeted, and because different skin lesions would have different molecules in differing concentrations, it should produce a diagnostic signature,” says co-inventor David McLean, a professor of medicine at the University of British Columbia. Even if the melanoma looks benign to the naked eye, the Raman spectrum signature will identify it.
The device compares a mole’s spectral signature to those in a database containing examples of melanoma and other skin diseases. It will help dermatologists decide whether to biopsy or not. And it could eventually be used by nondermatologists in areas where dermatologists are scarce, such as rural Canada, says McLean.
A danger that regulatory bodies will likely consider, however, is the chance for false negatives in such situations—that is, whether the device might dismiss a mole that turns out to be melanoma. Another concern is whether some dermatologists might use the device as a way to diagnose melanoma instead of using it to help them determine whether or not to do a biopsy. Other companies seeking to commercialize melanoma detection technology, including U.S.-based MelaSciences, which uses infrared scanning, are already facing such scrutiny at the regulatory level.
Whatever U.S. and Canadian regulatory agencies decide, there is a need for devices that can help identify melanoma, says Darrell Rigel, a professor of dermatology at NYU’s Langone Medical Center, and former president of the American Academy of Dermatology. “It’s a challenge to diagnose melanoma clinically. It’s subjective,” Rigel says. “And while it’s not so difficult with one spot, many people have lots of spots—how do you decide what to biopsy?”