Each In Situ dog trains for up to eight months, smelling samples of breath, plasma, urine, and saliva collected by doctors and sent to the foundation. After smelling more than 300 unique samples, dogs are able to distinguish between a healthy sample and a cancerous one. They also learn to “generalize” the smell, meaning they can transfer what they know about the smell from samples already tested to new, similar samples.
At In Situ, Dina Zaphiris has trained dogs to work with research teams at hospitals and universities, distinguishing healthy samples from cancerous samples for teams at Duke University and the University of California, Davis. Now, In Situ is preparing to roll out the first-ever hospital-backed program to use cancer-detecting canines among the public, providing early screening for firefighters in California, who are at high risk of developing cancer because of all the toxins they’re exposed to in fires, including California’s deadly wildfires.
Osa is a star of the cancer-detection program at the Penn Vet Working Dog Center. She entered the center as a puppy and tried all the careers available to her there. Osa ultimately found her niche on the cancer-detection team. She immediately loved the work and was always excited to go to a day’s training. These days, she lives with her handler in New Jersey and completes two or three cancer-detection sessions every week. The rest of the week, her trainer keeps her happy and busy with Agility and Obedience training, a fitness program, and live human searches. When she entered the program at Penn Vet, Osa was sometimes reactive toward people. But that’s all in the past now. Her work as a cancer-detecting canine has made Osa a happier, more confident, and more trusting dog.
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As Dina Zaphiris’s dog, ten-year-old Australian Shepherd Stewie has been sniffing cancer samples since she was eight years old. She loves swimming and playing with Dina’s other dog, Splitty, a year-old Border Collie. Like all the dogs Zaphiris trains at In Situ, Stewie works only in a laboratory setting. Three days a week, she goes to the lab to take turns sniffing samples with her cancer-detecting canine companions. But she never has to wait long for her turn . In fact, it only takes a dog 30 seconds to smell 10 samples. The work is so fun that it feels like play to Stewie and her stablemates. They always want to keep on sniffing after the day’s work is done.
The Science Behind a Dog’s Sniffer
In her book Nose of a Dog, research scientist Alexandra Horowitz notes that “most of what the dog sees and knows comes through his nose.” Depending on the breed, a dog’s nose has around 125 million to 300 million scent glands, while a human’s nose has around five million scent glands. That means that a dog’s sense of smell is around 1,000 to 100,000 times more sensitive than a human’s.
Research indicates that dogs are capable of detecting tiny traces of odors created by different diseases. How tiny? Around one part per trillion, or the equivalent of one teaspoon of sugar in two Olympic-sized swimming pools.
For their study, the researchers obtained urine from 12 men with biopsy-confirmed high-grade Gleason 9 prostate cancer and 38 men who had negative biopsies. Part of the urine specimens were sent to Medical Detection Dogs in the UK for diagnoses by Florin, a four-year-old female Labrador, and Midas, a seven-year-old female Wirehaired Vizsla. After training the animals with 5 cancer and 15 noncancer samples, the researchers used the remaining samples to test Midas’s and Florin’s skills. At each testing run, the dog examined a carousel containing three cancer-negative samples and one cancer-positive sample. After getting a whiff of each container of urine, the dog made a selection—Florin indicated a positive sample by standing and staring, whereas Midas sat in front of her choice. A correct choice earned the pup a well-deserved treat.
Both dogs accurately identified five out of seven prostate cancer samples. Out of 21 cancer-negative samples, Florin made the right decision 16 times and Midas 14 times. Overall, the dogs showed 71 percent sensitivity and 70–76 percent specificity. Mershin says the main reason for Midas’s and Florin’s moderate accuracy was because they received limited training, due to the limited number of urine samples available. With such a small number of test samples, Santiago Marco, a physicist who studies data analysis of sensors at the Institute for Bioengineering of Catalonia and the Barcelona Institute for Science and Technology, is not convinced that the dogs’ choices were made on the basis of cancer detection. “It’s not clear that they have very strong support for the claim that the canine olfaction is sufficiently sensitive or even specific,” says Marco, who was not involved in the study.
With their legendary sense of smell, dogs are adept at identifying the characteristic scents of cancers from breath, urine, and poop. But with trained cancer-sniffing pups in short supply, animals are unlikely to become widely available for routine diagnostics. Instead, Andreas Mershin wants man’s best friend to teach machine learning algorithms to sniff out diseases, and he plans to put this technology into your pocket. Mershin, a research scientist at the MIT Center for Bits and Atoms, says his eventual goal is to build electronic nose capability into smartphones.
The detection of a cancer signal by electronic noses isn’t a new concept, but those that have been developed so far still can’t match the accuracy of dog’s, says Mershin. To get closer to that ability, Mershin and his interdisciplinary team establish a proof-of-concept method for the integration of canine olfaction with machine odor analysis of prostate cancer in a study published February 17 in PLOS ONE.
Inspired by canines, Mershin and his colleagues sought to develop artificial intelligence that emulated doggie decisions. “The specific question we try to answer [in the study] is, what are the hurdles and challenges in taking the dog’s nose and its functionality and plugging it into your smartphone?” says Mershin, who leads MIT’s Label-Free Research Group, named for its disregard of boundaries between scientific disciplines.
Dogs Can Smell Cancer | Secret Life of Dogs | BBC Earth
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Lucy, a cross between a Labrador retriever and an Irish water spaniel, failed miserably at guide dog school. As she was curious and easily excitable, random scents distracted Lucy from her master’s path, and it wasn’t long before she was unceremoniously kicked out.
But her owners knew their smart dog held promise. They decided, if her nose was getting her into trouble (she was after all, bred to be a hunting dog), why not train her to sniff out something useful?
For the next seven years, Lucy learned to sniff out bladder, kidney and prostate cancer, and was even used in a study. Over the years, she has been able to detect cancer correctly more than 95% of the time. That’s better than some lab tests used to diagnose cancer.
Now, Lucy is part of one of the largest clinical trials of canine cancer detection. A British organization, Medical Detection Dogs, has eight dogs sniff out 3,000 urine samples from National Health Service patients to see whether they can discern who has cancer and who doesn’t.
Claire Guest is the CEO of Medical Detection Dogs. Her fox red Labrador, Daisy, caught her breast cancer six years ago when she was 45. “She kept staring at me and lunging into my chest. It led me to find a lump,” Guest remembers.
The tumor was deep in her breast. Her doctors said that by the time she would have felt it herself, the cancer would have been very advanced.
“Had it not been drawn to my attention by Daisy, I’m told my prognosis would have been very poor,” she said.
Dogs’ powerful noses have 300 million sensors, compared with a human’s measly 5 million. In addition, dogs have a second smelling device in the backs of their noses that we don’t have, called Jacobson’s organ.
That double smelling system allows trained dogs to detect cancer’s unique odors, called volatile organic compounds.
It took humans thousands of years to figure this out. In 1989, doctors at King’s College Hospital in London wrote in The Lancet about a woman whose dog persisted in smelling a particular mole on her leg. That mole turned out to be early-stage malignant melanoma.
Over the next 26 years, studies from France to California to Italy have concluded that dogs really can detect the smell of cancer.
Researchers in the current British study have set a particularly high bar. They want to make sure dogs are actually smelling cancer and not something else, such as old age or a particular set of symptoms.
In the study, dogs will circle a carousel holding eight evenly spaced urine samples, one from a cancer patient and seven from patients who don’t have cancer. At least one of those seven samples will be from someone about the same age as the cancer patient who had symptoms of cancer but didn’t actually have the disease.
Guest, whose group is running the study, said that if studies like hers continue to show the power of dogs’ noses, the animals might one day be used in conjunction with existing diagnostic tests, not instead of them. Scientists might also design a machine – an “electronic nose” – that mimics a dog’s powerful smelling abilities. “It’s very feasible,” Guest said.