This UK charity is building an e-nose based on dogs that can smell cancer

Back in 2008, Claire Guest started training dogs to detect the odor of bladder cancer… from her dining room.

As an animal behaviorist, she had read about the science and heard enough stories to believe dogs’ snouts, which have hundreds of millions of olfactory receptors (humans typically have just a few million) olfactory receptors, could track diseases. So she took samples from volunteers and people she knew to run tests.

“Even though it was a small-scale study, it was obvious the dogs could do it very reliably,” Gemma Butlin, head of communications and people engagement at Guest’s UK-based research organization and charity Medical Detection Dogs, told Healthcare Brew.

The initial research was published in 2010, and has since been built out under the organization to study how dogs can detect bowel cancer, bacterial infections, Covid-19, pseudomonas, urinary tract infections, Parkinson’s disease, malaria, and prostate cancer. It collects samples from organizations like Hull University Teaching Hospital National Health Service Trust and Milton Keynes University Hospital in the UK and Johns Hopkins in the US.

With prostate cancer, for example, the novel detection method was 71% sensitive and 70%–76% specific at identifying high-grade Gleason 9 prostate cancer in the samples, according to 2021 research.

“The science is very legitimate,” Bruce Trock, professor in the departments of urology, epidemiology, and oncology and director of the division of epidemiology in the Brady Urological Institute at Johns Hopkins, told us.

Their long-term goal is to build an e-nose that can do all the sniffing itself and “inform technology,” Butlin added. That’s because the charity is “never going to be able” to have enough dogs to send one into “every waiting room and tell everybody who thinks they might have cancer” that they should get tested, she said.

You get a treat. Dogs ideally begin training with Medical Detection Dogs at eight weeks old, Butlin said, with one year of socialization with volunteers. Then they kick off their “scent work.”

To start, dogs may be asked to find a tennis ball and are rewarded when finding it. Then training scales up to more difficult hiding places and smaller balls before there’s just a residue and they learn to search for the odor of the ball, Butlin said. Afterward, the dogs learn the scent of a disease the organization is studying.

At this stage, Butlin said, dogs are not meant to replace more traditional testing but instead be a first line of screening to help patients realize they may need to see a doctor.

“All of our work is geared toward early diagnosis,” Butlin said. “The earlier you can get checked out for these things, the better your survival rate is.”

With breast cancer, for example, the five-year survival rate is 99% when the disease is detected early in the localized stage, according to the National Breast Cancer Foundation. Butlin told us Guest’s own dog, Daisy, helped her detect her own breast cancer.

Dogs are ultimately sensing a difference between noncancerous cells and cancer cells, which use oxygen differently and consume more energy and nutrients while also emitting “different signals to other cells in their environment,” Trock said.

Paw-sible technology. In some cases, dogs will be sent into settings to sniff patients passively, but over the long term, researchers plan on developing the e-nose.

The charity has worked with tech company RealNose.ai for 10 years to develop technology that can do it without the snout.

“In the same way that your phone can scan you and tell you whether your blood pressure is high or you’ve had enough sleep…it might be able to tell a gentleman that his [prostate-specific antigen] levels are high and he’s at risk of prostate cancer,” Butlin said.

While Butlin doesn’t have an exact timeline for finishing the technology, she said she hopes it’s ready within 10 years.

“It’s fair to say [dogs] are the best biosensors on the planet at the moment. They are ahead of technology,” she said.

Across the pound. Back in the US, researchers are also working on understanding how dogs can detect disease.

The University of Wisconsin-Madison School of Veterinary Medicine, Indiana-based Purdue University, and the California-based nonprofit InSitu Foundation are all developing research and tools on the subject.

Stephanie Montgomery, CEO at the nonprofit American Kennel Club Canine Health Foundation, said the group is working in collaboration with researchers at the Penn Vet Working Dog Center to see if dogs can detect cancer in other dogs as well.

“Even though our mission is to advance the health of all dogs, a lot of times there’s benefit to humans,” she said.

E-noses, which are also being developed in the US, “have the potential to help in disease detection,” Trock said, as they remove potential human error from the testing process and are noninvasive. Though, he added, there’s still the potential for nonmorbid positives and requires a controlled environment.

“It’s likely that, just as with many other biomarkers currently in use or being investigated, e-noses will initially be used in conjunction with current standard of care methods, rather than as a replacement,” he said.