A laser-based tool that produces high-resolution images may help physicians better diagnose melanoma, according to Duke University, Durham, North Carolina, researchers who developed the technology.1
The tool uses 2 lasers to pump small amounts of energy (less than a laser pointer) into a suspicious mole. By analyzing the way energy redistributes in the skin cells and pinpointing the microscopic locations of different skin pigments, scientists can identify chemical differences between cancerous and healthy skin tissues, says Thomas Matthews, a Duke graduate student who helped develop the 2-laser microscopy technique.
The Duke team imaged 42 skin slices with the new tool, showing that melanomas tend to have more eumelanin, a type of skin pigment, than healthy tissue. With eumelanin as a diagnostic criterion, researchers correctly identified all 11 melanomas in the study.
They will further test the tool on thousands of archived skin slices to verify whether it can identify changes in moles that eventually became malignant. Even if the technique proves 50% more accurate than a biopsy, it will prevent about 100,000 false melanoma diagnoses, says Warren S. Warren, PhD, director of Duke's Center for Molecular and Biomolecular Imaging. Dr. Warren oversaw the development of the laser tool.
Typically, physicians use a light and a magnifying glass or a tissue biopsy to diagnose the disease. Dr. Warren says the former method is a 17th-century technique that is, at best, 85% accurate and that the tissue biopsy is not much more reliable.
Pathologists disagree over results of approximately 14% of biopsy diagnoses, according to a 2010 study, meaning that 2 pathologists would have opposite diagnoses on 214,000 to 643,000 melanoma cases each year, Dr. Warren notes.2
Most physicians favor removing suspicious moles when the analysis is not conclusive, along with surrounding skin tissue. Treatment costs, both monetary and otherwise, can be high. For that reason, physicians need more accurate diagnostic tools, the Duke team notes.
Dr. Warren received a $1 million challenge grant from the National Institutes of Health as part of the American Recovery and Reinvestment Act of 2009 to develop the imaging tool. The lasers are commercially available and could be added to the microscopes already used by pathologists.
Although suspicious moles still will have to be removed and imaged to detect cancer with the current tool, the team is researching ways that may enable dermatologists to scan moles without having to remove them.