Medical Device Daily Contributing Writer

Canadian and U.S. research agencies are joining forces to promote early diagnosis of oral cancer through research into a device that uses high-energy blue spectrum light to spot the disease.

The National Institute of Dental Craniofacial Research is so impressed with the VELscope, it has given the B.C. Cancer Agency (BCAA) and Simon Fraser University (Burnaby, British Columbia), a $2.5 million grant to fund an oral cancer-screening program using the device.

“The idea is to try and catch oral lesions that might turn into cancer that can't be seen through conventional examination,” BCAA research scientist Dr. Calum MacAulay told Medical Device Daily. “Those lesions are visible using this fluorescent visualization device.”

Oral lesions are typically discovered by dentists during routine examinations or by family physicians, who then refer the patient to an oral specialist. By the time a lesion is large enough to be detected by the naked eye, however, it may be too late.

About half of all cancerous oral cavity lesions in North America detected by conventional oral examination are late stage, so that, on average, half the patients will die within five years.

Miriam Rosen, director of the BCAA's Oral Cancer Prevention Program, told MDD that clinicians have not been able to identify changes in the oral cavity that might be a precursor to cancer.

“So any new devices that provide a better view of changes are really important from the standpoint of undertaking an effective intervention against disease, to prevent its development. They're also important from the standpoint of preventing its recurrence,” Rosen said

The VELscope works by shining high-energy blue or fluorescent light onto suspect tissue. Healthy tissue will emit a green color, while potentially pre-cancerous tissue “loses the green color and goes to a dark shadow,” a color change Rosen said is associated with changes “to both the biochemical composition and the morphology of the tissue.”

“When you have a mild dysplasia, we know only a portion of those early lesions will actually develop into a cancer,” she said. “So one of the big gold mines, if you like, has been to try to develop indicators that will let you know which ones are going to go forward to cancer and which ones just stay there or regress if left alone.”

Using fluorescent light to detect disease has been common practice for some time and was initially used to detect lung cancer using a scope inserted into the lung. MacAulay was one of the first to become involved in the use of fluorescence to detect skin cancer and helped developed goggles that enable clinicians to see the changes when blue light is shone on to suspect tissue.

The goggles, he said, have now “evolved” into the VELscope, a single, self-contained hand-held device, useful for both detecting new lesions and revising the margins in existing lesions prior to surgery.

“Typically, [surgeons] give themselves a cm for a margin of error and in some instances that wouldn't have been enough. This device is showing that the extent of the lesion and the boundary are actually much bigger than they originally thought they were.”

Earlier this year, MacAulay, along with Rosin, Dr. Pierre Lane and other researchers published results of an earlier study in which 44 patients had been examined using the VELscope. Using histology as the gold standard, the device was found to have achieved a sensitivity of 98% and specificity of 100% when discriminating normal mucosa from severe dysplasia/carcinoma in situ (CIS) or invasive carcinoma.

Their conclusion: The VELscope is “a suitable adjunct for oral cancer screening, biopsy guidance, and margin delineation.”

Today, Rosen heads a longitudinal study at the B.C. Cancer Agency that is using the VELscope to detect changes in their oral cavities of 400 additional patients. Of this group, 200 have existing cancers that are at risk of recurrence. But the remaining 200 have dysplasia, i.e., an early change that may or may not progress to a tumor, and it's these types of patients for whom the VELscope may be most useful.

Depending on the stage of tissue, cancer usually takes between two and five years to develop, Rosen explained, saying that “people are excited” because this device may be able to pinpoint early pre-cancerous lesions that can be treated long before becoming full-blown cancer.

“What we're finding with this device is that on occasion we will see areas with the device showing alteration through fluorescence that are not clinically apparent. When you look in the mouth, the clinician is not detecting them. And when we biopsy these areas they do have disease in them, either a cancer or something that's pre-cancerous.”

The VELscope, she said, has “added a new tool” that is helping researchers and clinicians understand early disease development and “mapping alterations” in pre-cancerous oral tissue. In the long run, Rosen said she believes this technology could find subtle changes in oral cavities up to 10 years before cancer develops, though for now the working window for the current project is about four years.

Rosen added that little progress has occurred in outcomes associated with oral cancer “for three or four decades.” Detecting localized Stage 1 oral cancer results in a survival rate of 80 %, a figure that drops to 20% for later stage cancers.

And she projected that earlier detection should reduce the number of oral cancer related deaths in Canada where about 20% of the population smokes cigarettes (a prime cause of oral cancer) and in the U.S. where the smoking rate is even higher.

For now, her goal is to get a more precise idea on just how effective her oral cancer screening program and the VELscope are in detecting oral cancer lesions.

“The second goal is the whole knowledge transference issue of how you train people on the appropriate use of the device and how you ensure that when they detect something that it is referred forward so that the disease is properly managed.”

Developed by Led Dental (White Rock, British Columbia) at a price of about C $5,000, the current version of the VELscope has been in use in Vancouver for only a few months. But MacAulay predicted that it would gain wider use in the rest of Canada and the U.S., with additional work to enhance the device.

He added: “There's some work with respect to optimizing the wave length of light, the fashion of illumination, and various modifications that can be made to the device – all from the point of view of cost and efficiency and ability to see the lesions.”