'Magic wand' could spot cancerous tissue during surgery
A team of experts from the UK and Hungary have developed an electronic surgical device that can tell whether a surgeon is removing normal or cancerous tissue.
The iKnife takes samples of smoke produced during 'electrosurgery' - used routinely in operating theatres to remove tissue while minimising bleeding - and analyses it for signs of cancer.
In a pilot study that will pave the way for large-scale trials, the iKnife correctly identified samples from 91 patients while they underwent cancer surgery.
The study's authors suggest that, if trials are successful, the device could ultimately reduce the length of operations, and lead to better cosmetic outcomes, reduced chances of a patient's cancer coming back, and even improved cure rates.
Their results are published in Science Translational Medicine.
Surgery is the mainstay of cancer treatment, and the NHS carries out more than 1.8 million diagnostic, curative, or palliative surgical procedures on cancer patients each year, according to James Kinross, study co-author and a colorectal surgeon at Imperial College London.
"Almost all of these involve electrosurgery to some degree," he says.
A major issue surgeons face is trying to remove all the cancer cells while preserving as much of the surrounding healthy tissue as possible.
This is normally done by taking a pre-determined 'margin' of healthy tissue around the observable tumour, based on surgical guidelines.
"The problem is, these guidelines are estimated based on retrospective analysis of large numbers of patient samples", says Kinross, and these don't necessarily apply to the individual a surgeon is treating.
If a surgeon is unsure whether tissue is normal or cancerous they can, under certain circumstances, send a sample for analysis in the hospital's pathology lab while the patient remains under anaesthesia.
This initial test can take between 20 to 30 minutes, while additional samples are frequently required, prolonging the length of the surgical procedure considerably.
"And as these are often done in a rush, there can be reliability issues," says Imperial College's Dr Zoltan Takats, who invented the device. "So for a long time, surgeons have wanted a 'magic wand' to tell the difference between normal and cancerous tissues."
The key insight that lead to the device's development, says Takats, was the realisation that the smoke generated by electrosurgery could be analysed in real time using a technique called mass spectrometry.
The result is the iKnife, which can be attached to existing, widely used electrosurgery equipment and is now in commercial development.
To test the device, the research team - based at several hospitals in Hungary and the UK - analysed a variety of tissue samples from 302 patients in the laboratory, resulting in 'fingerprints' for 1,624 cancerous and 1,309 non-cancerous tissues.
This created a reference database, which was used to analyse samples from patients undergoing surgery, and the results compared with standard laboratory analysis. The machine matched the accuracy of the laboratory results.
The results were welcomed by surgeons, who cautioned that larger trials were needed to confirm the study's promise.
"This is a promising and innovative technology, but we need to see results from much larger studies to confirm whether the data in this paper hold up," said Tim Underwood, a Consultant Surgeon and researcher at Cancer Research UK's Southampton Centre who is running the marathon to raise funds for research.
"From my point of view as an oesophageal surgeon, this device could prove useful in lowering the proportion of patients who have residual cancer following the removal of their oesophagus - currently we also have to give these patients radiotherapy."
But he cautioned that there were still unanswered questions over how the iKnife can be adapted for other surgical techniques, smaller 'keyhole' laparoscopic devices, rather than open surgery as has been tested so far.
Dr Emma King, Cancer Research UK head and neck cancer surgeon, also welcomed the development. "The iKnife is an exciting development to guide cancer surgeons during operations.
"If its usefulness is supported in further clinical trials, it could potentially reduce the time spent in theatre for many patients," she said.
The study was funded by the National Institute for Health Research (NIHR) Imperial Biomedical Research Centre, the European Research Council and the Hungarian National Office for Research and Technology.
Copyright Press Association 2013
- J. Balog et al. 'Intraoperative tissue identification using rapid evaporative ionization mass spectrometry.' Sci Transl Med 5, 194ra93 (2013) DOI: 10.1126/scitranslmed.3005623