DOGS THAT sniff out malignant cancers in human beings are swiftly becoming accepted as part of complementary medical treatment regime.
The Pine Street Clinic located in San Anselmo, north of San Francisco in wealthy Marin county. Pine Street is a ‘complementary’ medicine centre. It is from here that a research paper — peer-reviewed by mainstream scientists and copper-bottomed by statisticians at the University of California, Berkeley — is to be published next year in a respected American medical journal. It suggests that the humble dog could bring about a revolution in the early diagnosis of cancer as well as embarrass the medical technology industry and the technology minded majority of the medical profession.
The claim of the Pine Street Foundation, which runs the clinic, is this: that dogs, given as little as three weeks’ training, can, by smelling samples of people’s breath captured in a special tube, detect cancers of the lung and breast even in their earliest stages — and can do so to a level of accuracy as good as and beyond that being achieved in conventional hospitals by the latest Cat, Pet and MRI scanners.
In a scientifically supervised trial involving 55 lung cancer patients, 31 breast cancer sufferers and a control sample of 83 healthy patients, five Pine Street dogs achieved an accuracy rate in detecting cancers of between 88% and 97%. The dogs even seem able to detect with near-certainty the first, symptom-free stage of lung cancer — a condition that technology can distinguish only to a lower level of accuracy.
There are many caveats in making crude comparisons but according to Cancer Research UK, Britain’s biggest cancer investigator, scanners typically costing £1.2m plus £300,000 a year to run reckon to detect early-stage cancers to an accuracy of 85% to 90% — a lower rate than Pine Street’s dogs.
The dogs are taught to indicate a ‘positive’ find by holding out a paw for a treat. "Obviously, during double-blind testing the dogs received no treats as neither experimenter nor dog handler knew which breath samples were from cancer patients and which were from controls," said Michael McCulloch, the clinic’s research director.
The research findings will be published in March in Integrative Cancer Therapies, the journal of the University of Illinois, following a statistical analysis by the school of public health at Berkeley.
It represents a breakthrough for a small but persistent group of medics and other scientists in Britain and America who have been trying to demonstrate for nearly 20 years that dogs have exceptional diagnostic abilities with cancers ranging from malignant melanoma to breast cancer.
Last year a British project, the Amersham bladder cancer study, published a report in the British Medical Journal from a team at Amersham hospital, Buckinghamshire, that had trained dogs to detect cancer from urine to an accuracy rate of 41%.
This figure, low though it sounds, suggested that the dogs in the trial were correctly identifying urine samples at a three times greater-than-chance rate; one Amersham dog achieved 60% accuracy. The Amersham experiment gained much publicity, but was still regarded in medicine as more of a novelty than as a development of any practical use.
Another British team, which was working under Dr Barbara Sommerville at Cambridge University’s renowned veterinary school, ran out of its £42,000 grant money with its work incomplete and has just been denied a further three years’ funding.
Gill Lacey, 46, is a Buckinghamshire mother and the editor of a charity magazine and is convinced the dogs’ ability to sniff out cancer. She appeared in a documentary film about Pine Street’s work - Can Dogs Smell Cancer? which was shown on BBC4 last week and may be shown on BB 1 or 2 at a later date. She believes her life was saved when she was 19 by Trudii, her parents’ Dalmatian.
"I was working in London at the Royal National Throat, Nose and Ear hospital," she said last week, "and went one weekend to my parents’ home in Winchester.
"Trudii was drawn towards one mole on my leg and would sniff and nibble at it. There was something odd about her behaviour that made me think that whatever it was, it was unpleasant to her. She was suspicious of it."
It took several months of this behaviour by Trudii to get Lacey to go to hospital. "The truth is I was scared. Everything I’d read indicated there was nothing suspicious about the mole. It was tiny, it wasn’t growing or itching or changing.
"So I had no reason, other than the fact that the dog was sniffing at it, to go to the GP. But I’d been reading Richard Adams’ novel The Plague Dogs, in which lab dogs escape and pass the cancer lab and they know that it’s bad because it smells bad."
As it turned out Trudii had detected, apparently by smell, what was a malignant melanoma in its earliest stage. Lacey had to have a large portion of skin removed from her leg, but has had no recurrence.
"It’s the change in a dog’s behaviour that you notice, and its persistence," she said. "It wasn’t just something that happened once. You could pick up on something going on. You almost use a sixth sense of your own to understand what the dog is worried about."
Firmly against "doctor dogs" is Dr Richard Sullivan, director of programmes and centres at Cancer Research UK, which spends £230m a year on cancer studies. "Can you use dogs to detect cancer? No, you can’t. Be serious. Dogs carry disease," he says dismissively.
"Then there’s the huge quality control and health and safety problems. It would be interesting to know whether patients would trust a Cocker Spaniel over a diagnosis of whether or not they had lung cancer."
"What dogs may do, though, is provide a proof of concept. There may be some mileage in developing electronic breath tests. Machines don’t get tired. The dog has that fantastic kind of fuzzy intelligence, but being a biological device is also its big negative. But the main point is that this is a small sample and we believe the more people come into the sample, the more unreliable the dogs will be."
The cancer-sniffing dogs so far remain firmly part of "alternative" medicine and, as such, open to scepticism. But Jemima Harrison, writer and director of the BBC4 documentary, says that people should be open-minded: "Science knows some of the answers but it doesn’t know everything.
Having come late to science I’m a bit of a born-again reductionist. But the more you know about science, the more you realise it’s work in progress."