How dogs can sniff out cases of cancer.
Byline: DR MIRIAM STOPPARD
One of the most severe tests I had to face as a junior doctor was a middle-aged woman brought into A&E where I was working over Saturday night/Sunday morning. She was unconscious and the nurses said she was a drunk.
My nose saved me. Her breath smelled of pear drops - like nail polish remover - and propelled me to a diagnosis of a diabetic coma. The default treatment in this situation is glucose into a vein - and it worked.
Doctors use their noses as diagnostic tools quite often, but the capability of the human nose pales in comparison to those of dogs.
Dogs' powerful noses have 300 million sensors, compared with a human's measly five million. In addition, dogs have a second smelling device in the backs of their noses that we don't have, called the Jacobson's organ.
Human breath, urine and faeces contain trace amounts of chemicals (VOCs) from our metabolism. Studies have shown that the type and composition of the VOCs can be an indicator of diseases such as kidney, lung and breast cancers, asthma, sleep apnoea and C. difficile.
We know that dogs can detect minute concentrations of VOCs. Two studies in 2011 and 2012 used dogs to screen for colon cancer in faeces and detect lung cancer from a breath sample.
Now the charity Medical Detection Dogs, which trains canines to identify human disease by smell, is conducting the largest trial in the UK using the dogs to detect prostate cancer by testing urine samples from 3,000 patients. In training trials for the new study, the dogs had a 93% reliability rate at detecting prostate cancer in urine samples, considerably higher than in most lab tests.
If this trial, being conducted at Milton Keynes University Hospital, Bucks, is successful, the charity hopes that the screening provided by the dogs could be offered as a second line test to confirm or flag up an inaccuracy in the result of the traditional prostate specific antigen (PSA) test.
Dr Claire Guest, chief executive of Medical Detection Dogs, says: "Early diagnosis of cancer is a major challenge and we believe our work with dogs is something that could really change that.
"Britain has one of the worst rates of early cancer detection in Europe. The NHS needs to be bolder about introducing innovative new methods to detect cancer in its early stages.
"Our hope is that eventually we could offer a service where dogs can screen for particularly aggressive cancers and help save lives."
They had 93% success spotting prostate cancer