Dogs can be trained to become master cancer sniffers, using their keen noses to find cancerous fumes emanating from sick cells. If these puppies are so adept at smelling, why aren’t they currently using it to screen people for cancer? This sniffing is noninvasive and could help diagnose countless people.
The quick answer is that dogs excel in demanding circumstances, such as assisting law enforcement in tracking scents or directing search and rescue teams in disaster zones. However, smelling through thousands of samples to find a few that might be cancerous is difficult work with little reward.
Additionally, training these dogs requires time and effort, and even with extensive preparation, they could still miss a diagnosis if they’re having a bad day, experts told Live Science. [20 Weird Dog and Cat Behaviors Explained by Science].
But that doesn’t mean that dogs can’t be useful in the development of artificial cancer detection tools. Cancerous cells are known to release distinctive odors, but the precise chemical compounds that cause these smells are still unknown.
Giving canines specific cancerous samples to sniff and slowly removing compounds from the sample could help dogs detect cancer-specific odors. “You know you’ve taken out that component of the mixture that is specific to the cancer if the dog stops responding to the sample after several components are removed,” said Dr. Professor Hilary Brodie works at the University of California, Davis in the Department of Otolaryngology. Then, he said, researchers could examine these individual elements and create biochemical tests that could accurately screen patients.
There are many things that dogs can do, but Brodie told Live Science that he didn’t believe that population screening on a large scale was the direction things were going.
The first report on canines detecting cancer was published in 1989 in the British journal The Lancet. Two dermatologists described how a dog allegedly spent several minutes per day inspecting a colored lesion on its owner’s thigh and even attempted to bite off the area when she was wearing shorts in a letter to the editor. She requested that doctors examine the lesion out of concern, and they discovered that it was a malignant melanoma.
The doctors stated in the letter that the dog “may have saved her owners life by encouraging her to seek treatment when the lesion was still at a thin and curable stage.”
There were more dog-detection reports, but no high-quality, double-blinded studies were published until 2006, according to Dr. Austrian pulmonologist Klaus Hackner practices at Krems University Hospital Both the dogs and their handlers were unaware of which samples in the double-blinded studies were cancerous. ).
Numerous studies soon emerged demonstrating the ability of trained dogs to identify specific cancers by smelling biological samples like a person’s breath or urine. This is due to the fact that all cells, including cancer cells, emit volatile organic compounds (VOCs). According to Hackner, each type of cancer most likely has a unique VOC, which means it smells different from other cells.
Dogs are excellent animals for sniffing out disease because they have more than 220 million smell receptors in their noses, according to Hackner. In contrast, he claimed that humans only have “mere” 5 million smell receptors in their noses. [Why Do Dogs Have Whiskers?].
In about 6 months, Hackner said, most dogs can be trained to recognize the scent of a particular cancer. However, many studies used experimental designs that don’t apply to real-world situations. For instance, the dog was frequently given five samples, one of which was always a cancerous specimen. In reality, he said, a sniffer dog may only find four cancerous specimens out of a batch of 1,000, depending on the type of cancer.
The handler cannot reward the dog when it selects the correct specimen if neither the dog nor the handler are aware of which four of the 1,000 samples are cancerous, according to Hackner.
Hackner, whose 2016 work, which used a setup similar to what occurs in real-world settings, was published in the Journal of Breath Research, said, “I think this was one main reason why our study failed.” “We were unable to give positive feedback because, during the screening, neither of us knew whether the dog was correct or not. This was stressful for both the dogs and the handlers. “.
In order to prevent the dog from becoming bored after sniffing thousands of non-cancerous samples from patients, he suggested that there be always a cancerous sample planted in each set.
However, Brodie said that even if the setup could be modified to accommodate the dogs, it wouldn’t be a practical way to screen patients. To teach dogs to recognize the various forms of cancer that can affect humans would require an enormous amount of resources. While no test is perfect, at least doctors are aware of how accurate various tests, like mammograms, are as well as how frequently they result in false positives and false negatives. But these rates would vary for each dog, Brodie said.
Dogs can also get lonely, hungry, and “have bad days, just like you and I,” according to Brodie. “You would need to closely monitor their efficiency throughout their cycles.” “.
Instead, Brodie and Hackner said they envisioned dogs assisting scientists in developing and perfecting biochemical “nose” devices, known as e-noses, that could “sniff” patients and provide diagnoses. With the aid of dogs, these devices, which already exist for some medical conditions, could be made more sensitive and applicable to more diseases, according to Brodie. But the research isnt there yet, he noted.
In one project, Brodie and his colleagues investigated whether canines could detect volatile organic compounds from patients with head and neck cancer by smelling the breath the patients had exhaled into a container. However, after the dog trainer started advertising that her dogs could detect cancer, the researchers decided to put the project on hold.
“We didnt want to be affiliated with that,” Brodie said. “We wanted to show they’re detecting it, not just say they are and then show it,” Youve got to do the science first. This is not even close to or near prime time. “.
Laura is the editor of Live Science’s Lifes Little Mysteries and archaeology/history sections. She also reports on general science, including archaeology and paleontology. The New York Times, Scholastic, Popular Science, and Spectrum, a website devoted to autism research, have all published her work. She has received numerous honors from the Washington Newspaper Publishers Association and the Society of Professional Journalists for her reporting at a weekly newspaper close to Seattle. Laura graduated from Washington University in St. Louis with a bachelor’s degree in psychology and English literature. Louis and a masters degree in science writing from NYU. More about health.
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The Science Behind a Dog’s Sniffer
Research scientist Alexandra Horowitz writes in her book Nose of a Dog that “most of what the dog sees and knows comes through his nose.” A dog’s nose can have between 125 million and 300 million scent glands, depending on the breed, compared to five million scent glands in a human nose. In other words, a dog’s sense of smell is 1,000 to 100,000 times more acute than a person’s.
According to research, dogs are able to detect minute amounts of odors produced by various diseases. The equivalent of one teaspoon of sugar in two Olympic-sized swimming pools is how tiny it is—roughly one part per trillion.
History of Cancer Research and Dogs
When it comes to finding a cancer cure, researchers have been working toward a breakthrough for many years. Even though cancer care and treatment have advanced significantly, researchers are still searching for a cure. Cancer diagnosis has also taken a lot of time because the earlier it is detected, the better the patient’s prognosis and likelihood of successful treatment. But when it comes to diagnosis, a lot of people discover they have cancer when it is already advanced, which is frequently too late for treatment.
Dogs may actually prove to be far more effective at this than machinery and equipment, despite the fact that the medical industry uses a variety of high-tech tools and methods to try and detect and diagnose cancer as early as possible.
In fact, it has been demonstrated in the research done thus far that dogs can detect human cancer in its earliest stages, which can be crucial for delivering effective treatment. Some dogs are credited with literally saving their owners’ lives by spotting cancer in the early stages.
Similar to humans, dogs have demonstrated the ability to recognize individuals with lung cancer based only on a sample of their breath. Even though it was a small study and the rate of prediction was marginally lower than in the study involving urine detection, this field of study is still encouraging. In fact, the British National Health Service has authorized additional study into canine disease detection.
According to research, dogs occasionally possess the inert ability to detect an illness in a person before the owner is even aware of it themselves. Additionally, trained dogs can recognize disease-specific disease markers. Combining these facts supports the notion that dogs can detect cancer.
When a person is ill, dogs may become overly clingy, guarding, and protective of that person. If someone approaches them, they might become agitated and exhibit behaviors like growling, barking, or dropping their ears. Other dogs will concentrate on a certain area of the body, which turns out to be a sign of where cancer will develop. When this happens, dogs may paw or nuzzle the area, continually sniff it, whine, or howl.
Many of us have heard anecdotal tales about dogs’ propensity to detect illness in their owners. This talent may serve as evidence of the close relationship between humans and dogs. Or, simply evidence of the superior scent-detection abilities of canines.
Keep in mind that there is ongoing research into how well dogs can identify the presence of cancer in humans. Larger-scale studies will be needed to fully understand the mechanisms at play as well as how man’s best friend might someday aid in the early detection of various cancer types. It is still an exciting area for research.
FAQ
Is my dog trying to tell me I have cancer?
According to research, dogs can identify a variety of human cancers. Cancers leave distinct traces, or odor signatures, in a person’s body and bodily secretions, similar to many other diseases. These odor signatures are created and released by cancer cells or healthy cells that have been affected by cancer.
Do dogs sense cancer in humans?
Dogs Trained to Detect Cancer According to a 2022 study article published in Canine Medicine and Genetics, that highly developed olfactory system enables dogs to detect subtle odors released by cancer cells known as volatile organic compounds, even at very low airborne concentrations.
What do dogs do when they know you have cancer?
Some dogs will continually sniff you, and it might be difficult for you to move your dog away. Other people may lick or even bite at lesions on your body in an effort to treat your cancer.
Can dogs sense of smell cancer?
Dogs Have A Stronger Sense Of Energy And Smell, Which Allows Them To Interpret Human Emotions Before Humans Do Dogs have a strong sense of energy and smell, which allows them to get the whole story from just a scent. In addition to these, they can also detect human illness and demise.