Scientists say breath tests to detect cancers could be available in GP surgeries in just five years.
Clinical trials have begun for a cheap and quick system that tests for traces of cancers in air exhaled by patients.
The technique is aimed at detecting cancers of the gut, including those of the oesophagus, stomach, pancreas and colon.
Experts say it could also be used to pinpoint cases of liver cancer.
After a patient breathes into a bag, their exhaled air is transferred to steel tubes and the gases are passed over an absorbent material.
This material is then placed in a mass spectrometer where levels of different volatile compounds of the gut can be measured.
These volatiles change concentration when a tumour is present.
Prof George Hanna, of Imperial College London, told the Observer: “We have been working on this technique for more than 15 years and have now reached the stage where we are going through final clinical trials.
“If these are successful, we could see cancer breath tests deployed in doctors’ surgeries in a few years.
“I anticipate that it will take another five years or so before we get cancer breath tests up and running in GP surgeries.
“Dogs can smell cancers in humans. In addition, we have breathalysers that can detect chemicals in the breath.
“So creating cancer breath tests was an inevitable goal.”
