Scientists have invented a surgical instrument that can tell surgeons whether the tissue they are cutting into is cancerous or not.

The so-called ‘intelligent knife', or ‘iKnife', was developed by a team from Imperial College London in the UK.

As part of the first study to test the instrument, it successfully diagnosed tissue samples from 91 patients with complete accuracy, providing information to surgeons in less than three seconds. Laboratory tests usually take up to 30 minutes to reveal the same information.

The scientists explained that if a person has cancer involving a solid tumour, the best treatment is usually removal of the tumour. Some healthy tissue is usually removed as well, as it is often extremely difficult, if not impossible, to tell if a tissue is cancerous simply by sight.

In some cases, the patient must undergo a second operation to remove cancerous tissue that was missed the first time around. This happens in around one in five cases of breast cancer for example.

Sometimes, patients are left under general anaesthetic while removed tissue is sent to a laboratory to be examined. However, the iKnife removes this need.

The instrument is based on a commonly-used technology known as electrosurgery. Electrosurgical knives cut through tissue using an electrical current. This minimises blood loss and vaporises the tissue. The smoke that is created by this process is usually sucked away via extractor systems.

However iKnife inventor, Dr Zoltan Takats, felt that this smoke could actually contain important biological information. He therefore connected an electrosurgical knife to an instrument used to identify the chemicals in a tissue sample. This is known as a mass spectrometer.

As part of the study, the iKnife was used to analyse tissue samples from over 300 surgery patients. In 91 tests, the iKnife successfully identified the tissue type, achieving the same results as the traditional post-operative laboratory method.

"These results provide compelling evidence that the iKnife can be applied in a wide range of cancer surgery procedures. It provides a result almost instantly, allowing surgeons to carry out procedures with a level of accuracy that hasn't been possible before. We believe it has the potential to reduce tumour recurrence rates and enable more patients to survive," Dr Takats said.

Meanwhile, according to study co-author and professor of surgery at Imperial College London, Lord Darzi, when operating on someone with cancer, the aim is to take out as little healthy tissue as possible, while removing all of the cancer.

"There is a real need for technology that can help the surgeon determine which tissue to cut out and which to leave in. This study shows that the iKnife has the potential to do this, and the impact on cancer surgery could be enormous," he said.

Dr Takats added that while this study focused on cancer, the iKnife can be used in other scenarios, such as identifying tissue with an inadequate blood supply.

Details of these findings are published in the journal, Science Translational Medicine.