Dogs put nose to job of fighting cancer
TORONTO — Veterinary student and Toronto native Rachel Wallach said now that studies have proven that dogs can smell cancer in humans, scientists should switch their focus to putting the discovery into practice.
“All the research has gone into ‘Can they?’ The answer is yes. They can absolutely smell these disease markers,” said Wallach, an Anne and Max Tanenbaum Community Hebrew Academy of Toronto graduate and third-year University of Glasgow veterinary student.
A study carried out by German researchers and published in the European Respiratory Journal last month showed that dogs were able to detect lung tumours in 71 per cent of patients.
Wallach explained that the researchers trained dogs to detect “volatile organic compounds,” which are linked to the presence of cancer, using their keen sense of smell.
“There is actually no human contact with the dogs… Patients who had lung cancer [as well as] patients from a control group who were healthy had to breathe into a tube with a cotton swab at the bottom and then it was sealed,” Wallach explained.
“Dogs were trained to positively ID based on reward, the ones with cancer. After they were put through rigorous training protocol, they were given a blind sample and it was a double blind, so even the handler didn’t know which were positive and which were negative.”
The results from this study showed the dogs identified 71 lung cancer samples out of 100.
“Now that we know that they can, how do we move forward and use it to our advantage?” she asked.
Wallach, who spent her summer in Toronto and has been doing clinical rotations at several practices in the city, said she became “fascinated” with the work being done in this field.
“There is something magical about the fact that dogs can do that.”
After learning about a summer research program offered by her school, Wallach obtained a grant to do a literature review on cancer-sniffing dogs.
“In the last decade or so, there has been research about whether dogs can smell disease. Whether it is cancer or diabetes or even parasitic infections,” she said.
But Wallach added that despite the number of similar studies, there is no consistent training method for the dogs.
“There is no system that exists in the research sector. There is no protocol on how to train these dogs. I think in order for the research to continue, you have to have a base method of training and evaluation. If you evaluate one way and another lab evaluates another way, you’re comparing apples to oranges,” Wallach said.
“What I’m looking to do is compare the dogs that have been trained for these projects with the dogs that have been trained… [to detect] explosives and drugs. I’m comparing the ways in which these dogs have been trained and used and evaluated.”
She said she is also polling opinions about the studies because many researchers say that although the results are remarkable, they don’t see how these dogs can be used in practice.
But if researchers can find a way to put this theory into practice, the method could serve as a way to detect cancer earlier than some medical tests can.
“The dogs are so amazing at early diagnosis that they are able to detect it before a patient even has symptoms or before a doctor even says ‘I think I’d like to test for something.’”
Wallach said that in one of the first cancer-sniffing dog studies, dogs were trained to detect prostate cancer in patients’ urine.
“All but four dogs kept identifying this one urine sample from a control patient who was supposed to be a healthy patient. So the researches were concerned enough to let the person know. Further tests were done and it turned out that the person had a kidney tumour.”
She said a similar story involving the recent study had dogs smelling breast samples.
“The dogs kept IDing this one sample of a control patient and it turned out the patient had been in remission from lung cancer,” Wallach said.
“When something sets off the dogs’ radar I think people have been concerned enough to say, ‘OK, let’s look into that.’”