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November 18, 2011
Four-Legged Bio-Detectives Are Pioneering a Health Revolution

Dogs' keen sense of smell are creating a health revolution when it comes to early diagnosis of cancer. Trained ordinary household dogs can now detect early-stage lung and breast cancers by merely sniffing the breath samples of patients.

Daisy the Labrador is being taught to sniff out cancer. She is one of the world's first bio-detection dogs -- trained animals that may one day revolutionise medical diagnosis.

We all know that dogs have far more powerful noses than humans -- indeed their sense of smell is up to 100,000 times better than ours.

The ability of dogs to detect cancer was first discovered in 1989, and reported in the medical journal The Lancet . A woman's pet had alerted her to the presence of melanoma by constantly sniffing the skin lesion on her leg. Subsequent studies have shown dogs can smell melanoma and bladder cancer.

"I think all of these [studies and observations] are saying this ought to be looked at more carefully and ought to be taken seriously," said James Walker, director of Florida State University's Sensory Research Institute in Tallahassee.

That skill has, of course, been put to good use for decades, in the form of drug-sniffing dogs at ferry terminals and airports as well as the Army's bomb detection canines.

But, in recent years, a dedicated team of researchers has been developing what is potentially an even greater breakthrough.

Earlier this year, German research discovered that dogs could sniff out lung cancer from breath samples of sufferers.

The four dogs in the study learned to get it right 71 per cent of the time, far too high to be mere coincidence.

Closer to home came the story of British pensioner Maureen Burns, who made headlines when her collie-cross Max started sniffing her breath and nudging her right breast -- where it turned out she had a tiny cancerous tumour developing that doctors hadn't yet picked up.

Watching over them is the 'veteran' of the centre, nine-year-old brown cocker spaniel Tangle. He was one of the original dogs that took part in the first cancer sniffing research in the world when he was little more than a puppy in 2002.

So how did it all come about? Dr Guest, it turns out, had long suspected that dogs may have cancer-detecting qualities.

Having worked for almost 20 years for Hearing Dogs For The Deaf, she had come across several stories about dogs that had started to display peculiar behaviour when their owners had developed early-stage cancer.

'There seemed to be lots of anecdotal evidence -- even a colleague of mine, Gill, told me about how her pet Dalmatian had started licking and sniffing a mole on her leg when she was in her 20s,' recounts Dr Guest,

'She couldn't even be in the same room as the dog.

'Eventually, she decided to go to the GP to have it removed -- and a biopsy revealed it was malignant melanoma, the most aggressive form of skin cancer.'

Dr Guest teamed up with respected surgeon Dr John Church (whose other research has involved bringing back the use of maggots for cleaning wounds) in 2002 to try to prove this phenomenon was more than just coincidence.

The results of their study, in which the dogs were 56 per cent accurate, sparked interest around the world. Since then, Dr Guest has been improving methods to make the dogs more accurate (using rewards has brought about the biggest change, perhaps not surprisingly).

Time to see it in action. Daisy's trainer Rob takes me into a white room with the metal carousel in the centre.

From a cardboard box, he removes 12 plastic pots, each filled with just 0.5ml of urine.

'The dogs work with a mix of samples donated by local hospitals,' he says.

'Some of the patients are healthy, some have other diseases and one has cancer.'

So far, bladder cancer has been the focal point for testing, but the charity is about to launch a new trial into prostate cancer to broaden their research.

Rob knows which sample is the cancerous one -- the dogs are simply learning to recognise the scent, rather than diagnosing cancer.

He admits that at this stage, no one really knows what compounds in the samples the dogs are detecting -- only that it must be there. 'It's difficult because, essentially, we are working backwards -- we don't know yet what it is that they can smell, but finding out they can smell something gets us one step closer to identifying it.'

He attaches one vial to each spoke of the carousel, which can be spun around (to avoid the clever dogs working out where the cancer sample is put each time simply by the position).

With all 12 in place, Daisy enters with Dr Guest. She is fed a treat (donated Royal Canin food) and then Dr Guest calls: 'Seek!' Daisy weaves around the carousel, stopping for half a second at each vial to sniff before she carries on. Then she reaches the sixth position.

She stops, sits and stares back at Dr Guest. Only when she hears a 'click' from a training device in his hand does she hurry over to her trainer for  another reward.

So did she get it right? Of course she did -- and another four rounds show she is spot on every time. It is staggering to watch.

'They transform as soon as their red 'bio-detection' coats are on -- it's like a uniform,'  says Rob.

How on earth did Daisy, and the  other cancer dogs, learn to do this? The first step, according to Dr Guest, is picking the right dogs.

'We look for highly driven dogs that enjoy hunting for the sake of it,' she explains. 'Working labradors, spaniels and collies are often well-suited.

'They need to be very nose-driven -- many dogs that live with humans become more reliant on their eyes.'

The dogs tend to come from  rescue centres or are donated by breeders who support the charity's work. When they first show up, often as puppies, they are put through obedience training -- dogs can't be sniffer trained until they can  follow and obey voice commands.

Next, they start simple scent work and problem-solving -- I'm shown a training toy the centre uses which looks like a child's wooden block game, but different treats can be hidden under the blocks for the puppy to find.

After about 14 to 16 months (although they don't put a time limit on it), the centre moves on to advanced sniffer training using urine samples and the handheld 'clicker' which is pressed if the dog identifies the correct cancer sample.

'It pinpoints the exact time when the dog is doing something you like, and then you reward them afterwards,' says Dr Guest. 'They learn that the behaviour associated with the click leads to the treat.'

To begin with, they are given 'high reward' treats like a piece of smelly cheese or tripe -- but as they become more used to it, they move on to more simple dog biscuits and food, or even a tennis ball. These are dogs, after all.

Having spent a day at the centre, there's no disputing the incredible talent of these dogs and their  trainers. So will they be the key to identifying cancers earlier than any doctor can?

It's early days yet. But so far, the signs are that man's best friend could turn out to be an even greater asset to mankind.


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