Laser better differentiates cancerous and healthy cells

A new laser technology developed at Duke may now more easily and accurately identify skin cancer.

To reduce excessive health care costs and the number of false diagnoses of melanoma—the deadliest form of skin cancer—the laser tool uses multiphoton technology to differentiate between cancerous and healthy tissue. Rather than slicing and cutting out possibly dangerous moles, the laser identifies their chemicals and structure.

“An analogy we like to use is taking a black and white picture and adding color,” said Thomas Matthews, a graduate student and co-author of “Pump-Probe Imaging Differentiates Melanoma From Melanocytic Nevi,” which appeared in Wednesday’s Science Translational Medicine. “We add chemical contrast or information to structural imagery. This allows doctors to access for the first time new information about melanoma in the skin.”

When looking at the same slide, two pathologists will disagree one in seven times about whether or not a mole is cancerous, said Warren Warren, director of Duke’s Center for Molecular and Biomolecular Imaging and a co-author of the paper. Since these disagreements are generally resolved by deciding that the mole in question is cancerous, about 10,000 to 20,000 patients in the United States are falsely diagnosed with melanoma each year, he said.

To the naked eye, normal moles and melanoma look very similar, making it difficult to determine which type a patient has, Warren said. As a result, doctors typically abide by the motto “when in doubt, cut it out,” he added.

“[Doctors are using] the technology of the 17th century—what they do is look at a mole and look under the magnifying class,” Warren said.

Building a laser is a feasible project because it is less invasive than the traditional method, said Mary Jane Simpson, a graduate student and co-author on the paper. Patients want to be able to go to the doctor, get scanned and know what is wrong with them, she explained.

The National Institute of Health Challenge Grant has provided $1 million in funding for the research, Warren said, adding that the grant is extremely difficult to be selected for as it is awarded to only 2 percent of those who apply.

“There are a lot of people who ask questions about the stimulus money and what [it actually bought],” Warren said. “This million dollar grant could save many, many millions of dollars of health care costs.”

In the short term, using the laser would be more expensive for the patient than traditional methods, Simpson noted. If a false positive for melanoma is prevented, however, the patient would avoid all of the costs associated with treatment. The laser would also be economically feasible for large dermatology departments such as Duke’s, where one laser could be used for many patients, Simpson said.

Before being approved by the Federal Drug Administration and released into the market, this product will still need to undergo many more trials, Warren said. The lab is currently improving their slides and working with mice studies.

The medical laser uses less power than a laser pointer—there is no reason it should be dangerous for patients, Warren said. When the laser is ready, it could influence more than just the diagnosis of melanoma.

“Some people are trying to push it right into the clinic, and, on the other end, people are trying to learn more about the basic science,” Warren said. “What can this tell me about the biochemistry of the mole? This could lead to preventions or cures.”


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