Compiled by BioPhotonics staff
DURHAM, N.C. – High-resolution
images from a new laser-based tool could help doctors better diagnose melanoma,
the deadliest form of skin cancer.
The tool, developed by researchers at Duke University, probes
skin cells using two lasers to pump small amounts of energy – less than that
of a laser pointer – into a suspicious mole. Scientists then can analyze the
way the energy redistributes in the skin cells to pinpoint microscopic locations
of different skin pigments. It’s the first time that scientists have been
able to identify chemical differences between cancerous and healthy skin tissue.
The team imaged 42 skin slices with the laser tool and found that
melanomas tend to have more eumelanin – a kind of skin pigment – than
healthy tissue does. They used the amount of eumelanin as a diagnostic criterion
to correctly identify all 11 melanoma samples in the study. Results of their findings
appeared in the Feb. 23, 2011, issue of Science Translational Medicine (doi: 10.1126/scitranslmed.3001604).
The new method will be further tested using thousands of archived
skin slices to verify whether it can identify changes in moles that eventually did
become cancerous. It could prevent more than 100,000 false melanoma diagnoses, even
if it is only 50 percent more accurate than biopsies.
Previously, doctors used a light and a magnifying glass or tissue
biopsy to remove suspicious skin cells. They would inspect the cells under a microscope
to detect signs of the disease. In 14 percent of biopsy diagnoses, pathologists
were uncertain whether the sample cells were cancerous. They followed the “when
in doubt, cut it out” philosophy and, if they were not sure about the health
of the tissues around the diseased cells, they would remove those as well, costing
thousands of dollars.
Seeing such a great need for a more accurate way to diagnose melanoma,
the researchers set out to develop the new imaging tool. It now is commercially
available and would need only to be added to the microscopes that pathologists already
use to diagnose melanomas. Suspicious moles still would have to be removed from
a patient and then imaged to detect cancer, the scientists say.
The researchers are working on imaging skin cancers grafted onto
mice to see whether the tool could become a device for dermatologists to scan a
mole without removing it.