Dogs can detect prostate cancer in men almost every single time, "spectacular" research has found.
Tests showed dogs correctly detected the killer in 98 per cent of cases after sniffing the urine of men.
Experts hailed the findings and called for more support for the "tested, time-old" technique.
"It is particularly exciting that we have such a high success rate in the detection of prostate cancer, for which the existing tests are woefully inadequate."
Prostate cancer is the most common cancer in men in the UK, with more than 40,000 cases diagnosed every year.
The Italian study involved two German shepherd dogs sniffing the urine of 900 men - 360 with prostate cancer and 540 without. Scientists from the Department of Urology at the Humanitas Clinical and Research Centre in Milan found one dog got it right in 98.7 per cent of cases, while the other was correct in 97.6 per cent of cases.
They said the dogs were able to detect specific volatile organic compounds in the urine, but said an important question remained of how a dog would find it in daily practice. The conclusions echoed similar, previous research by Dr Guest who found a 93-per-cent reliability rate.
Dr Guest said there was a "reluctance to embrace this tested, time-old technology", but dogs could pick up a scent in a dilution of one to a thousand parts.
There is no single test for prostate cancer, but the most commonly used are blood tests, a physical examination or a biopsy.
"Over the years, millions of pounds of NHS funding has been poured into the traditional test methods, and yet there has been little improvement in their reliability," Dr Guest added.
"This has caused a huge waste of resources, not to mention the distress to the impacted individuals.
"Moreover, the detection dogs provide alternative solution that yields consistently accurate results. If our detection dogs were a machine, there would be huge demand for them."
Medical Detection Dogs, which is based in Milton Keynes, trains specialist canines to detect the odour of human disease. It also trains Medical Alert Assistance dogs to help people with life-threatening health conditions go about their daily lives.
The charity announced last year that it was to carry out trials on whether dogs could detect breast cancer in women.