A specially trained female black Labrador retriever picked out early stage bowel cancer in 33 out of 36 cases by smelling the patients’ breath alone – a 90 per cent success rate.
The dog was even more accurate when given stool to smell, correctly identifying the faeces of someone with early stage bowel cancer with 98 per cent accuracy (37 out of 38 cases).
However, the former is potentially more exciting as it holds out the possibility that a person could be “breathylised” for early stage bowel cancer.
This would be a much more pleasant and less invasive testing method than is currently available.
At the moment in England, all men and women aged 60 to 74 are eligible for screening every two years.
They are sent do-it-yourself kits to test for tiny amounts of blood in their stool, called faecal occult blood (FOB) tests.
The result indicates whether a colonoscopy or sigmoidoscopy is required, which involves putting a probe up the anus to check for abnormalities.
However, the FOB tests are unpleasant to do and not particularly accurate.
The researchers, from Kyushu University in Japan, believed their black Lab was able to identify certain chemicals – called volatile organic compounds (VOCs) – produced by cancerous cells.
While one option would be to train up teams of dogs, they thought this was impractical “owing to the expense and time required”.
Writing in the journal Gut, they concluded: “It is therefore necessary to identify the cancer-specific VOCs detected by dogs and to develop an early cancer detection sensor that can be substituted for canine scent judgement.”
Bowel cancer is Britain’s second biggest cancer killer, claiming over 16,000 lives every year.
Mark Flannagan, chief executive of the charity Beating Bowel Cancer said: “This study looks interesting but it is for the scientists to verify whether these findings could lead to future developments for screening.”