Cancer could soon be picked up through a simple breath test, after researchers launched a clinical trial to see whether molecules in the mouth could identify disease.
In tests run by Cancer Research UK, breath samples from 1,500 people will be collected in the hope that odorous molecules called volatile organic compounds (VOCs) can be detected.
All cells produce VOCs through their normal day-to-day operation, but if their metabolism changes, such as in cancer, they release a different pattern.
If the trial is successful, it would mean that cancer could be spotted quickly before it has spread, when it is easier to treat and when chances of survival are greatest.
Professor Rebecca Fitzgerald, lead trial investigator at the Cancer Research UK Cambridge Centre, said: "We urgently need to develop new tools, like this breath test, which could help to detect and diagnose cancer earlier, giving patients the best chance of surviving their disease.
"Through this clinical trial we hope to find signatures in breath needed to detect cancers earlier - it's the crucial next step in developing this technology."
The breath biopsy test has been developed by Cambridge-based biotech firm Owlstone Medical and is the first that works for multiple cancer types, paving the way for a universal breath test that could be quickly administered by a GP.
The trial will start with patients with suspected oesophageal and stomach cancers and then expand to prostate, kidney, bladder, liver and pancreatic cancers in the coming months.
The trial is recruiting patients to Addenbrooke's Hospital in Cambridge who have been referred from their GP with these specific types of suspected cancer.
They will be given the breath test prior to other diagnostic tests. Patients will breathe into the test for 10 minutes to collect a sample, which will then be processed in Owlstone Medical's Breath Biopsy laboratory in Cambridge.
Rebecca Coldrick (54), from Cambridge, was one of the first to sign up to take part in the trial.
She was diagnosed in her early 30s with Barrett's oesophagus, a condition where the cells lining the oesophagus are abnormal, which can be an early warning sign of cancer.
Currently, Ms Coldrick needs an invasive endoscopy to check for disease every two years, but if the new breath test is successful she would no longer have to undergo the procedure.
"Initially, I thought I might feel a bit claustrophobic wearing the mask, but I didn't at all.
"I think the more research done to monitor conditions like mine and the kinder the detection tests developed, the better," she said.