Dogs Can Smell Cancer


Daisy the labrador is hard at work on a project that could change your life and mine.

In her smart red jacket, she wanders around a metal carousel in a small centre outside Milton Keynes, sniffing at the different scents that are attached to its 12 spokes. Then she stops.

She’s found what she’s looking for and looks expectantly up at her handler — she knows that when she recognises this specific smell, she will soon get an edible reward.

While Daisy enjoys the process (and her dog biscuits) her actions are more than just a game — they have huge implications for all of us.

Because what this seven-year-old dog is sniffing is a selection of samples from a local hospital. And she has just located the only one that came from a cancer patient.

Daisy, quite simply, 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.

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.

A dog that can smell cancer before doctors can diagnose it?

If it sounds far-fetched — a case of wishful thinking rather than genuine canine skill — then there is solid scientific theory behind it.

It’s believed that cancers produce volatile chemicals that dogs can be trained to smell, which could have dramatic implications for early diagnosis of the disease.

Does this mean that at some point in the future, every hospital and GP’s surgery could be equipped with a ‘sniffer dog’ to pounce on anyone who has cancer?

No. For now, researchers are simply hoping to prove that if they demonstrate categorically that cancer does have a generic smell, then scientists could work towards creating a machine (known as an ‘electronic nose’) to perform the same function as a dog’s wet nose can: screening breath or urine samples to search for ‘cancer scent’ with even greater  ability than specially-trained dogs.

Unlike painful biopsies, this would undoubtedly make the process of diagnosis less invasive and far quicker — and more likely to be picked  up earlier.

As Claire Guest, a specialist in human and animal behaviour and the doctor responsible for the British research into cancer sniffer-dogs, says: ‘One of the largest misunderstandings we face is that people think we are trying to say that dogs are better than machines — we’re not.

‘There are already machines which act as ‘electronic noses’ that are designed to identify chemicals such as cocaine, and this is what we are trying to do with cancer.

‘Of course, no dog is going to be 100 per cent — but at the moment there is no machine out there that can do what the dogs are doing. Cancer detection is extremely invasive, so imagine if it could be picked up simply by a urine sample or blowing into a tube?’

Dr Guest has invited me along to spend the day at the headquarters of her trailblazing charity, Medical Detection Dogs, so that I can witness these ‘doctor dogs’ in action.

Not only does the centre train dogs to sniff cancer, it’s also responsible for training ‘medical alert’ dogs which live with people who have health problems.

They have taught 22 dogs to recognise when a diabetic’s blood sugar gets low and alert them to stop hypoglycaemia, aid narcoleptics by working out when an attack of sleep paralysis is about to start — and may soon be able to teach dogs to tell when someone with a severe allergy is about to have an allergic episode.

This all relates to the same idea — that dogs can recognise the minutest changes in smell when certain processes happen in the human body.

‘We are only at the start of working out everything that dogs can detect,’ Dr Guest says. ‘It would seem that almost any medical event has an odour change. The clever thing  is that the dogs are able to work out what the norm is, and when  it changes.’

While only a small group of people (mostly diabetics) have benefited from the services of the medical alert dogs so far, it is the charity’s cancer research work that could really make a difference to millions, and I’m here to see what the fuss is all about.

On arrival at the centre in Buckinghamshire, I’m greeted by a pack of dogs of all shapes and sizes, scampering around on a patch of grass outside like any other beloved pets out for a walk in the sunshine.

Shouldn’t life-saving dogs behave a little more seriously? Rob Harris, the training co-ordinator, assures me that this ‘down-time’ is essential.

‘This is their time to come out and refresh their noses. It’s a great place for them to run around,’ he says.

The dogs don’t spend every day at the centre, but usually come in two or three times a week. They either live with charity workers or full-time dog walkers — none spends its days kennelled.

At present, there are ten ‘cancer dogs’ in the training programme, but they’re never all here at once.

Today, it is Daisy the labrador that will demonstrate her skills, but hurtling around her at playtime is Ozzie, an  18-month-old border collie (he has even been to Crufts), Kizzy, a three-year-old cocker spaniel, and two new recruits, Alice, a six-month-old golden retriever, and Midas, seven months old, a Hungarian Vizsla (a breed of sleek red hunting dog).

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).

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

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.

The dogs need to be very nose-driven — many dogs that live with humans become more reliant on their eyes

‘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.

source :

Leave a Reply

Your email address will not be published. Required fields are marked *