Laser Technology Might Help Doctors Diagnose Melanoma
WEDNESDAY Feb. 23, 2011 -- Researchers say they've developed a new and potentially more accurate way to diagnose melanoma lesions, using laser technology.
The laser equipment spots key differences in pigmentation between healthy skin and cancerous tissue, the team explained.
As currently envisioned, the new screening procedure would still require excision of suspicious moles (otherwise known as a tissue biopsy) before the laser-imaging diagnosis could be attempted. However, preliminary indications suggest that the approach will be more precise than current screening procedures, which can often leave patients with inconclusive results and unnecessary surgeries.
Researchers from Duke University's Center for Molecular and Biomolecular Imaging (CMBI) in Durham, N.C., discuss the technique in the Feb. 23 issue of Science Translational Medicine. The work was funded by a grant from the U.S. National Institutes of Health.
Melanoma is the deadliest form of skin cancer, and the fifth- and sixth-most common cancer overall for American men and women, respectively, according to background information in the study. In 2009, over 68,000 new cases of melanoma were diagnosed in the United States, according to the American Cancer Society, and about 8,700 patients died from the disease.
Pathologists have been somewhat frustrated by standard techniques designed to catch the disease, the study authors noted. These techniques include the use of a light and magnifying glass and the removal and analysis in the laboratory of sample cells. The researchers pointed out that even lab analysis yields only about 85 percent diagnostic accuracy.
The Duke research team, including CMBI director Warren S. Warren and Duke graduate student Thomas Matthews, tried out the lasers on 42 skin slices, pumping two beams -- smaller than those emitted by everyday laser pointers -- at the target moles. The laser energy that was absorbed shifted around the sampled skin cells, highlighting microscopic differences in skin pigmentation.
Because melanoma cells happen to have more of a particular pigment called "eumelanin" than do healthy cells, this dynamic allowed the researchers to easily identify signs of cancer. The method was 100 percent accurate in identifying all 11 cases of melanoma present in the test slides, the study authors said in a university news release.
The Duke team noted that testing is ongoing, including an effort to develop a method that would allow dermatologists to laser screen for melanoma without the need for the lesion to be removed.
In the opinion of Dr. Vijay Trisal, assistant professor of surgical oncology at the City of Hope Cancer Center in Duarte, Calif., the current move to fashion a new screening tool for melanoma "is a very worthy effort."
"And that is because in addition to biopsies not always showing clear-cut results, we also just do too many of them," Trisal noted. "Out of every 100 people who undergo a biopsy today, just one will prove to be malignant, which suggests that we really should be doing less of them in the first place. And I expect that . . . the further development of this kind of new diagnosis approach will eventually lead to just that: reducing our need for these kind of unnecessary procedures."
For more on melanoma diagnosis, visit the American Cancer Society.
Posted: February 2011