Wondering about that mole? Lasers can spot out cancers

One suspicious mole, 2 tiny lasers, and a 3-D image. A new diagnostic technique can better separate out the cancerous moles from harmless ones, cutting millions in unnecessary costs. Available now.
Written by Janet Fang, Contributor

A new 3D imaging technique using 2 lasers can better separate out the cancerous moles from harmless ones – decreasing unnecessary skin cancer tests, stressful false positives, and also millions in healthcare costs a year.

It’s hard to figure out if a spot, bump, or mole is potentially cancerous. There are all kinds of unofficial ways to tell: is it spongy, is it raised, does it change shape?

In the case of melanoma – the leading cause of death among skin cancers with 8,700 just last year in the US – a misdiagnosed lesion could have deadly consequences. But false positives are also upsetting, leading to unnecessary surgeries, biopsies, and emotional distress.

To spots signs of disease, doctors typically (1) use a light and a magnifying glass or (2) perform a tissue biopsy, by removing cells to examine under a microscope. But using a lens and a light is a “17th century” technique that’s only 85% accurate at best, and tissue biopsy is not much more reliable, says study coauthor Warren S. Warren of Duke.

So, to address all the unnecessities, the team developed a technique to look at the chemical changes in skin pigments that occur in melanoma.

Melanocytes are cells that produce a pigment called melanin, responsible for skin and hair color. And there are 2 main types of melanin in melanoma lesions: eumelanin (brown/black) and pheomelanin (reddish). Turns out, higher levels of eumelanin are found in cancerous moles.

Their tool probes into a suspicious mole using 2 lasers – using less energy then a laser pointer. Then they watch the way energy redistributes in the skin cells, pinpointing the microscopic locations of different pigments.

The probe figures out the ratio of these 2 melanins and helps generate hi-res 3D images of tissue (pictured).

After looking at 42 skin slices, the team identified 100% of all the cases of melanoma present. This new imaging technique can prevent 100,000 false positives diagnoses – even if it’s only 50% accurate, Warren says.

When studying biopsied tissue, doctors typically follow the ‘when in doubt, cut it out’ philosophy, but the first and second tissue biopsies can cost thousands of dollars.

These lasers are already commercially available and could be added to the microscopes pathologists already use to diagnose melanomas. That cost is about $100,000, and suspicious moles would still have to be removed and imaged. The team is working on making the tool capable of scanning a mole without removing it.

The study appeared in Science Translational Medicine this week.

Image: Science/AAAS

This post was originally published on Smartplanet.com

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