How sniffer dogs can detect cancer

THIS week I witnessed a genuine medical marvel while working with detection dogs. We are all familiar with the drugs dog at the airport, but who would have thought of using sniffer dogs in clinics?

Yet dogs such as labradors are now not only being used to catch dealers, they are also helping doctors screen and diagnose disease. A dog has 220 million smell receptors, while a human has only five million, so it’s not surprising that a dog’s sense of smell is one thousand times better than that of a human.

From search and rescue to smuggling, it’s now not uncommon to see a dog at work. They can sniff things out where humans can’t — and now they are sniffing out anything from cancer to low blood sugars in brittle diabetics (those with uncontrolled type 1 diabetes).

Before I worked with detection dogs earlier this week, I was sceptical about what they could really do. However, I was astonished at what I saw — namely, a gun dog actually sniffing out cancer on a urine specimen.

This was a proper experiment in a controlled environment. The dog picked up the prostate cancer in the specimen, something the standard prostate-specific antigen test (PSA) blood test often misses or interprets incorrectly. The dog got it right first time and all he wanted for his efforts was a biscuit.

So how on earth do they do it? These are just regular dogs, but they are trained for this purpose. Certain volatile compounds are released in the urine and also in the breath of cancer patients and the dogs can detect these odours with a single sniff.

It’s not just cancer they can detect either — dogs can be trained to detect blood sugar changes in diabetics, narcolepsy crises and low levels of cortisol in the blood. They can become a potentially life-saving companion for someone with a chronic condition, such as the brittle diabetic, whose blood sugar crashes wildly. The dog can recognise that the blood sugar levels are dangerously low and then raise the alarm.

Will the situation ever arise where we regularly use dogs in the clinic to diagnose people? Probably not. Yet if we can work out what it is the dog smells and extrapolate that into a test, then we could save a lot of lives and a lot of time.

It’s far easier to provide a specimen of urine or a breath sample than doing a blood test — the results are instant. Of course it’s not infallible, but neither is any of the current testing. Medicine is constantly looking for new ways to screen and detect disease and, personally, I think now’s the time to bring the dogs in.