For more than 70 years there has been little improvement in the way doctors perform a procedure called Mohs surgery, an operation to remove skin cancers on the face. Now, the can rely on the help of a high tech camera which creates more reliable and accurate scans.
Currently, patients undergo a visual examination followed by a skin biopsy to determine a diagnosis of cancer. Surgeons can’t get a clear picture of the extent of the damage and use their best judgment to identify the boundary between the tumor and the patient’s normal skin (called the margin).
Dr. Victor Neel MD, Ph.D., Director of the Dermatologic Surgery Unit at Massachusetts General Hospital is one of the medical professionals testing the device. He notes that “It’s impossible to see skin cancer margins with your eyes. I’ve done 25,000 cases at Mass General, and about 65 to 70% of the time I get it all in the first pass. That’s been my stable success rate for about 10 years and I can’t seem to do better than that. There’s a limitation to what the unaided eye can see”.
Optical polarization imaging (OPI) works much like a regular camera. “We’re not actually looking for tumor cells, per se,” explains Neel. “We’re hunting for deformed collagen which will tell us where the tumor begins and ends”. It uses polarized lenses, blue light, and some computer analysis to instantly image the targeted area.
“It’s a very inexpensive and simple, yet elegant technology,” added the doctor. “It would allow Mohs surgeons to take a picture of the surgical site in real time and construct a surgical plan based on what they are now able to see”.
In trials so far, OPI has shown outstanding accuracy (high nineties percentage) in predicting tumor edges though Neel says the machine is meant to complement Mohs surgery and not replace it. The team is working on reducing the size of the bulky prototype at the moment.
“I’m looking back at the 25,000 cases I’ve done at Mass General, and I don’t want to do another 25,000 the same way. It’s exciting to see a change on the horizon”.