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The Life-saving Work of Medical Detection Dogs


At its headquarters in Buckinghamshire, UK charity MEDICAL DETECTION DOGS is harnessing a time-old technology to pioneer a brand new method of early cancer detection. Remarkably, the charity trains dogs to recognise the smell of human disease before even the symptoms are felt.

DR CLAIRE GUEST, animal behaviourist and director of the charity Medical Detection Dogs, has dedicated the last ten years to exploring the possibility that dogs could be the solution to the ever more pressing problem of early cancer detection.

She set the charity up in 2008 in partnership with Dr John Church, a former orthopaedic surgeon. Four years previously, both had worked on the first significant study to investigate the possibility that dogs could detect human cancer.

Dr Guest explains: "For hundreds of years humans have worked with dogs in every aspect of our lives. Dogs have helped us catch our food, protected us, found us when we're lost and consistently provided loyalty and affection.

"They are tuned into our moods and our behaviour. If you take into account this intimate relationship and combine it with their extraordinary sense of smell, which is powerful enough to detect one drop of blood in three Olympic-sized swimming pools of water, the idea they can pick up the odours related to human disease is really not so hard to believe."

As life expectancy has risen and healthcare improved, the threat of cancer has grown. One in two nowadays will be diagnosed with cancer. In spite of this, little progress has been made in the sphere of early detection.

Prostate cancer is a salient example. The traditional prostate-specific antigen (PSA) tests have a 75 per cent false positive rate. This leads to three in four men with a positive result unnecessarily undergoing a second round of painful, invasive tests.

In contrast, secondary screening provided by the dogs would involve a painless, non-invasive and cheap process of sending a urine sample to the bio-detection unit in Buckinghamshire.

Working one at a time with a trainer, the cancer detection dogs are presented with eight urine samples on a carousel, one of which contains cancer. The dog sniffs each sample until it finds the one that contains the cancer volatiles. The dog then sits and stares fixedly until the trainer confirms a correct identification and rewards the dog with a treat.

The detection dogs never come into contact with the patients who volunteer to donate their samples.

In these types of training trials, the cancer detection dogs have recorded 93 per cent reliability.

The charity is currently completing two training trials, one into the detection of breast cancer using breath samples and another into prostate, bladder and kidney samples using urine samples. The research will be double-blind tested and peer reviewed.

Is Dr Guest frustrated by the slow process of turning her research into a functioning secondary screening service available on the NHS?

"Yes and no. Of course it's frustrating that right now there are people all over the country - and indeed across the world - who cannot be screened by the dogs instantly and receive the quick, accurate answer to this most important question of all.

"However, you would expect - and demand - the level of scrutiny we have faced to be applied to any new technology in healthcare. It is people's lives that are at stake and so it is vital we can prove conclusively that our dogs achieve a high level of reliability."

While the cancer work makes steady progress, the second arm of the charity is already saving the lives of sixty individuals across Britain with long-term conditions on a daily basis. Of these, the majority suffer from brittle type 1 diabetes, a severe form of the condition which means sufferers get no warning signs that their blood sugar is nearing crisis levels.

Claire Moon, a diabetes nurse from Cambridge has brittle type 1 diabetes herself and was one of the first to receive a dog from the charity.

"I used to stay awake, or wake up every hour overnight, testing my blood sugars 20 times a day," she says. "I feared not waking up in the morning because my body has stopped giving me warning signs, such as dizziness or blurred vision, when my blood sugar dips dangerously low."

Now Claire has Magic, a bounding golden Labrador who remains at her side wherever she goes. "Magic has alerted me hundreds of times and saved the NHS thousands of pounds by preventing emergency call-outs. I used to be rushed to hospital in a critical condition about once every month.

"Before Magic, I had to give up my job; now he's a firm favourite on my ward. I call him the blond bombshell!"

Gemma Faulkner at only 13 years old has had to deal with more than most people her age. Diagnosed with brittle type 1 diabetes a month before her third birthday, her condition has meant frequent stays in hospital and the fear of lapsing into a coma at night.

Thanks to the charity, she now has Polo, an energetic black Labrador. Polo is firmly one of the Faulkner family.

Gemma's mother recalls the first time Polo alerted during the night to Gemma having a hypo. "He came into our bedroom and came up to me. I knew he was telling me there was a problem. We tested Gemma's blood and her blood sugar levels had fallen dangerously low."

For Gemma, Polo is more than just a life-saver: "He is my new best friend. I love him so much. We have great fun running through puddles and playing ball. He makes me feel safe and confident - I can't imagine life without him!"

Dr Guest is ever pragmatic, but nevertheless remains resolutely optimistic about the future. "We know we have revealed a remarkable ability dogs have to detect dangerous chemical changes in our bodies. These highly sensitive bio-detectors should not be underestimated just because they possess waggy tails!"

The charity receives no government funding and relies entirely on charitable donations. For more information please visit:

This article was published originally in Pets Magazine:

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