Dr Claire Guest was preoccupied with thoughts about work as she took her dogs for a walk one grey February evening in 2009. A long-term dream to use sniffer dogs to detect early signs of cancer had hit an impasse.
Claire, an animal behavioral psychologist, was convinced the animals could sense abnormal cancer cells through smells emitted by the skin, urine or even in the breath. Her first clinical research, published five years earlier, had shown it was possible to train dogs to detect cancer in samples supplied by patients.
Claire, an animal behavioral psychologist, and dog Daisy, who spotted her cancer
Since then, the accuracy of the dogs’ detection had risen to 73 per cent. But Dr Guest’s findings were being dismissed by some in the medical establishment – and her plan for a team of dogs to become a ‘second line’ detecting unit, specializing in hard-to-spot cancers such as pancreatic and prostate, was dismissed as hokum. As Claire recalls: ‘One leading cancer specialist said publicly: “You can’t possibly have a dog in every doctor’s surgery, so I can’t see the relevance.”
‘But what I envisaged were dogs in satellite units, across the country. They don’t need direct contact with individuals, because samples of breath and urine can be brought to the dogs to record their reaction.’
That February evening, Claire opened the boot of her estate car to allow her dogs out. While Tangle, a cocker spaniel, and a friend’s Yorkshire terrier jumped out of the car and ran into the park, their tails wagging, Daisy, a labrador, refused to follow.
As Dr Guest, now 50, recalls: ‘Daisy seemed to be pawing at my chest. She bumped against my body repeatedly – I pushed her away, but she nuzzled against me again, clearly upset.
‘She pushed me so hard that it bruised me. Her behavior was totally out of character – she was normally such a happy dog, who would never hesitate to race after the other dogs.’
‘I felt the tender area where she’d pushed me, and over the next few days I detected the tiniest lump.’
A few days later she went to her GP who referred her to a consultant. He thought it was a cyst, but said he would do a mammogram to be sure.
‘He was correct – the bump was a perfectly harmless cyst,’ says Claire. ‘But further in the breast tissue was a deep-seated cancer.’ It was caught very early and she had a lumpectomy and some lymph nodes removed, as well as six months of radiotherapy.
‘I was 46, and the specialist told me that by the time a lump had become noticeable, this cancer would already have spread and my prognosis could have been very different.
‘Just as I was doubting the future of dogs being used to detect cancer, my own pet labrador saved my life.’
Now, five years and several trials later, Daisy has sniffed 6,000 samples of urine and detected more than 551 cases of cancer with a diagnostic accuracy of 93 per cent.
Claire’s charity, Medical Detection Dogs, now has 12 dogs who live with host families and come to work from Monday to Friday at the charity’s headquarters near Milton Keynes, detecting traces of cancer from urine and breath samples.
They are trained by sniffing urine samples of people with cancer and rewarded when they single out these samples from other urine from non-cancer sufferers.
Claire says: ‘We published the first report into dogs detecting cancer in 2004 in the British Medical Journal, showing that our dogs correctly identified bladder cancer in 22 out of 54 cases – our success rates are now 93 per cent.’
Using dogs to diagnose a disease with such potentially serious consequences as cancer may sound bizarre but the concept is being considered seriously by scientists.
In 2010, for example, Japanese researchers showed that dogs can detect colorectal cancer from a breath sample, while in 2012 the European Respiratory Journal published research that found dogs could identify lung cancer in breath samples.
Claire’s charity is now conducting a trial with Buckinghamshire NHS Trust and Milton Keynes Hospital NHS Foundation Trust with samples from thousands of patients – the work is funded by the trust and charity donations.
‘If we have much more evidence, the plan is that the dog can be used as part of the cancer screening process – backing up the results of clinical tests.
‘A lot of cancers are difficult to detect in early stages,’ says Claire. But malignant cells produce changes in volatile organic compounds, and it’s these compounds which dogs are believed to detect in urine samples. ‘Dogs can detect odors at concentrations as low as one part per trillion, identifying scents which the human nose could never detect,’ says Claire. ‘We have five million sensor receptors dedicated to smell – dogs have 300 million.’
Professor David Billington, Pro Vice Chancellor of the University of Buckingham, who specializes in researching treatments for cancer and diabetes, believes the dogs’ skills are useful.
‘The dogs can detect cancer in the urine of patients with prostate cancer more reliably than the PSA test’, he says, referring to the blood test typically used to detect levels of prostate specific antigen, a protein linked to the disease. ‘A positive PSA test is followed up by a multi-needle biopsy, which is unpleasant and invasive.
‘If medics could use dogs to detect cancer from urine as well as using the standard blood test, they can use both factors to decide who needs to undergo a biopsy. It would save the health service a huge amount of money, spare patients unnecessary procedures and save lives.’
Claire’s work with dogs was inspired by meeting Gillian Lacey, editor of the magazine published by the charity Hearing Dogs for the Deaf. Gillian’s dalmatian Trudii helped diagnose her skin cancer. The dog became agitated about a mole that appeared on Gillian’s right leg while on holiday when she was 19.
As Gillian, now 55, recalls: ‘I hadn’t given it a second thought, but Trudii was really disturbed by it – she kept sniffing it, then licking and nibbling it. Her strange behavior – directed only at me – continued for eight months.’
The dog’s behavior persuaded Gillian to go to the GP.
‘When I told him the dog had sniffed out this mole, he said it was amazing what dogs can sense, but he didn’t think my mole looked sinister.’
Even so he removed the mole under a local anesthetic and two weeks later she was diagnosed with a malignant melanoma, which claims more than 2,000 lives in the UK every year. Gillian had surgery to remove an area of flesh 4in by 3in in size.
‘When I returned home after ten days in hospital Trudii took no notice of the area again. I’m convinced it was the smell of cancer which had bothered her so.’
As well as cancer-sniffing dogs – or canine olfactory detection, to give the process its technical name – the charity also trains medical alert dogs. These warn owners of the odor changes linked to a life-threatening medical event, such as dangerously high or low blood sugar levels in diabetic owners. The medical alert dogs – which cost £5,000 each to train – can also warn owners who have severe allergies, or narcolepsy (where the sufferer suddenly falls asleep) if they are in danger of collapse.
Professor Billington, who is also adviser to Claire’s charity, explains: ‘I know a nurse with type 1 diabetes who had been rushed to hospital in an ambulance a dozen times in a year. Thanks to her dog alerting her, she’s able to start working again.
‘These people are getting their lives back again. Day and night, their dogs remain by their side, smelling their breath and observing their body language and facial expressions, searching for the slightest change or sign that something is wrong.’
Scientists are now developing electronic systems (e-noses) that mimic the way dogs detect the smell of cancer.
Medical Detection Dogs is helping in this work by supplying statistics on reliability of dogs and their findings on how long the volatile compounds survive once exposed to air, for instance.
Among those supporting the charity as a trustee is Betsy Duncan Smith, wife of Iain Duncan Smith. She became interested in the charity’s work following her own diagnosis of breast cancer in 2009.
‘What the Medical Detection Dogs do is truly amazing. We know dogs are 93 per cent reliable in recognizing the odor of prostate cancer volatiles.
‘We also know they have consistently strong results for bladder and renal cancer and have the potential to detect breast, lung and – hardest of all to diagnose – pancreatic cancer.
‘It is incredibly exciting to think of what a difference they could make, providing quick, painless early detection.’
Article reposted from:
Written by: Amanda Cable