Surgery is often the best way to treat solid cancers. Surgeons have a problem over how much tissue to remove. Too little and the patient may have to have repeat surgery. Too much could affect bodily functions or cause unnecessary disfigurement. The current practice is to use experience, confirmed by lab tests on tissue samples, that the whole cancer has been removed removed. These take time so it is not practical to take samples as the operation progresses and wait for the response that you have not hit healthy tissue before paring back more and retesting.
Now scientists at Imperial College, London have come up with a solution by ingeniously combining two existing technologies into what has been dubbed the "iKnife".
The iKnife is based on electrosurgery, a technology invented in the 1920s that is commonly used today. Electrosurgical knives use an electrical current to rapidly heat tissue, cutting through it while minimising blood loss. In doing so, they vaporise the tissue, creating smoke that is normally sucked away by extraction systems
The clever bit is that the iKnife sucks up the smoke coming from the cut and feeds it directly into a mass spectrometer. That analyses the smoke, can determine whether the area is cancerous or not and give an almost instant read-out. The team have found that there are unique chemical signatures to the different types of organ and whether they are cancerous.
Tests in real theater situations were conducted in 91 cases. The test data were confirmed as 100% accurate in parallel conventional lab testing. The potential for saving many hours of surgeons' time waiting for lab results or having to conduct second operations is enormous :
(O)ne in five patients who have a breast lump removed still need a second operation to clear their tumour. For lung cancer the figure is about one in 10
Trials using the iKnife are going ahead in 3 London hospitals. If these are successful the system could be rolled out to all British hospitals in five years. While the idea of combining the two technologies is amazingly simple - and obvious if you think about other endeavors where similar techniques are use (the Mars explorers for example which use lasers to vaporize material), the application to medicine requires the mass spectrometer results to be accurately identified:
researchers first used the iKnife to analyse 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 works by matching its readings during surgery to the reference library to determine what type of tissue is being cut, giving a result in less than three seconds.
There are also possibilities for using the knife/mass spectrometer/database combination for other diagnostics. It may be able to tell what bacteria are infecting tissues and even be an almost-instant check for food inspectors to check meat. One suggestion is to identify horse meat in batches of beef, a recent scandal in Europe.