'Intelligent knife' helps surgeons identify cancer tissue

Scientists at Imperial College London have developed a surgical instrument that detects cancerous tissue in seconds.

The advance, led by Dr Zoltan Takats, has the potential to improve patient survival rates and save money for health authorities by reducing the need for secondary operations.

The intelligent knife, or iKnife has been adapted from a suite of chemical profiling technologies built by Waters Corporation and is in use at St Mary’s Hospital, Hammersmith Hospital and Charring Cross Hospital.

It is based electrosurgical knives that are commonly used in operating theatres. Originally developed in the 1920s, electrosurgical knives use an electrical current to heat tissue, allowing surgeons to cut through it whilst minimising blood loss. The heated tissue vaporises and gives off an aerosol that is normally extracted from the operating theatre.

Dr Takats has adapted the electrosurgical knife so that it extracts the aerosol and feeds it via a tube to a mass spectrometer in the operating theatre, which lets the surgeon know via a display if the tissue being operated on contains cancerous cells.

James Kinross, clinical lecturer in surgery at Imperial said in-theatre improvements have focused on reducing trauma to patients but there is little biological information available to the surgeon that could add to the quality of a procedure and the outcome for the patient.

Surgeons currently remove tumours with a margin of healthy tissue but it is often difficult to tell by sight which tissue is cancerous. According to Imperial College, one in five breast cancer patients who have surgery require a second operation to fully remove the cancer. In cases of uncertainty, the removed tissue is sent to a lab for examination while the patient remains under general anaesthetic.

‘If you’ve got a melanoma which is 4mm thick you’ve got to remove 3cm of tissue,’ said Kinross. ‘It really isn’t adequate. It isn’t precision surgery and it certainly isn’t personalised.’

A new study published in Science Translational Medicine shows how iKnife analysed tissue samples collected from 302 surgery patients, recording the characteristics of thousands of cancerous and non-cancerous tissues, including brain, lung, breast, stomach, colon and liver tumours to create a reference library.

The iKnife matched its readings during surgery to the reference library to determine what type of tissue is being cut, giving a result in under three seconds.

The technology was then transferred to the operating theatre to perform real-time analysis during surgery. In all 91 tests, the tissue type identified by the iKnife matched the post-operative diagnosis based on traditional methods.

According to Imperial, surgeons were unable to see the results of iKnife’s readings during testing but the team hope to carry out a clinical trial to see whether giving surgeons access to the iKnife’s analysis can improve patients’ outcomes.

‘The next stage is to do some formal clinical trials … where we’ll look at a range of cancers and possibly inflammatory bowel disease, where we’ll use decision making with and without iKnife. That is what we’ll be commencing this year,’ said Prof Jeremy Nicholson, head of the Department of Surgery and Cancer at Imperial.

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.