An experimental surgical scalpel is helping surgeons target only cancerous tissue when they remove a tumor. The iKnife — or "intelligent knife" — “sniffs” the smoke produced as it cauterizes the tissue, distinguishing malignant cells from surrounding healthy tissue.
From the moment patients wake up after an operation to remove a cancerous tumor, the first question most ask their surgeons is, “Did you get it all?”
Jeremy Nicholson, head of the Department of Surgery and Cancer at Imperial College London, where the iKnife technology was developed, says that is a difficult question to answer with certainty, because even the best surgeons often have trouble distinguishing cancerous from healthy tissue.
“You can’t absolutely guarantee that, but ... what you can say is that this sort of technology guarantees a great deal more precision about what you cut out, so you are much more likely to have removed all the offending material, whatever that is, and you are also much more likely not to have cut out good stuff," he said.
That iKnife technology is made possible by electrocautery, a technique that uses an electric current to cauterize tissue in order to seal it as the surgeon operates.
The process produces a smoke which is full of hazardous chemicals. The iKnife sucks the smoke into a mass spectrometer which rapidly analyzes and weighs about 1,000 different biochemicals. Nicholson says different tissues, including cancerous tumors, give off different molecular signatures.
As the surgeon cuts, the iKnife reveals boundaries between the tumor and healthy tissue in less than one second.
"The question in the surgeon’s mind is to cut or not to cut," said Nicholson. "And this can help you make that decision."
Writing in the journal Science Translational Medicine, Nicholson and colleagues describe how the intelligent knife accurately distinguishes suspicious from healthy tissue in 91 samples, compared to the standard practice of analyzing tissue under a microscope that’s been removed during an operation, which usually takes 20 to 30 minutes, often while a patient is still under anesthesia.
Nicholson says the iKnife can also determine whether a tumor has spread, based on its biochemistry and molecular signature.
“What’s quite extraordinary is if you’ve got a secondary tumor, the smoke actually tells you where the primary was," he said. "That in the future could potentially be very important."
Nicholson says researchers will now begin formal human clinical trials, comparing the effectiveness of iKnife — developed by Imperial colleague Dr. Zoltan Takats — to a conventional scalpel in removing cancerous tumors.
