As reported today by the Associated Press, in London an experimental “smart” knife was able to detect cancer in tumors from 91 patients. A member of the team which developed the knife utiilzed it on a piece of animal muscle during a demonstration at St Mary’s Hospital in London on July 17.
The experimental surgical knife can assist surgeons in making sure all cancerous tisues has been removed. Surgeons typically use knives that vaporize tumors as they cut, producing a sharp-smelling smoke. The new knife analyzes the smoke and can instantly signal whether the tissue is cancerous or healthy. In contrast, surgeons now have to send the tissue to a pathology lab for interpretation and wait for the results while the patient is still on the operating table. Even in the best hospitals, it can take about 30 minutes to get an answer but even then doctors cannot be entirely sure, so they often remove a bit more tissue than they think is strictly necessary. If some cancerous cells remain, patients may need to have another surgery or undergo chemotherapy or radiation treatment.
Suspecting the smoke produced during cancer surgery might contain some important cancer clues, Dr. Zoltan Takats of Imperial College London designed a “smart” knife hooked up to a refrigerator-sized mass spectrometry device on wheels that analyzes the smoke from cauterizing tissue. The smoke picked up by the smart knife is compared to a library of smoke “signatures” from cancerous and noncancerous tissues. Information appears on a monitor: Green means the tissue is healthy, red means cancerous, and yellow means unidentifiable.
The new knife and its accompanying machines were made for about $380,500, but scientists said the price tag would likely drop if the technology is commercialized.
Scientists tested the new knife at three hospitals between 2010 and 2012. Tissue samples were taken from 302 patients to create a database of which kinds of smoke contained cancers, including those of the brain, breast, colon, liver, lung and stomach. That was then used to analyze tumors from 91 patients; the smart knife correctly spotted cancer in every case.
The study was published Wednesday in the journal Science Translational Medicine. The research was paid for by groups including Imperial College London and the Hungarian government.
Dr. Takats said that the knife would eventually be submitted for regulatory approval but that more studies were planned. He added that the knife could also be used for other things like identifying tissues with bad blood supply and identifying the types of bacteria present.
Some experts said the technology could help eliminate the guesswork for doctors operating on cancer patients. “Brain cancers are notorious for infiltrating into healthy brain tissue beyond what’s visible to the surgeon,” said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society. “If this can definitively tell doctors whether they’ve removed all the cancerous tissue, it would be very valuable.”
Still, Dr. Lichtenfeld said more trials were needed to prove the new knife would actually make a significant difference to patients. Early enthusiasm for new technologies hasn’t always panned out, he said, citing the recent popularity of robotic surgery as an example. “It expanded very rapidly but is now hitting some bumps along the road,” he said.
Dr. Lichtenfeld said it’s unclear whether more widespread use of the smart knife will actually help patients live longer. He said studies should also look into whether the tool cuts down on patients’ surgery times, their blood loss and the rate of wound infections.
“This is a fascinating science, and we need to adopt any technology that works to save patients,” Lichtenfeld said. “But first we have to be sure that it works.”