Dogs that smell cancer are being examined in a large clinical trial in Britain in order to determine their effectiveness. The British organization, Medical Detection Dogs, aims to further research the incredible ability of dogs that can accurately detect the disease, according to News Max.
One such example of a dog that can smell cancer is Lucy, a Lab and Irish water spaniel mix. Lucy has showed promising results over the years and she has been accurate more than 95 percent of the time in detecting bladder, kidney, and prostate cancers. The current research will have Lucy and seven other dogs smell 3,000 urine samples provided by the country’s National Health Service to look for cancer.
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Before going more in depth on the subject, some scientific facts about dogs incredible sense of smell should be brought up for those unaware of the scope of the olfactory abilities of sniffer dogs. To some, the premise of cancer sniffing dogs may sound like science fiction. According to pbs.org, scientists say that dogs’ sense of smell is 10,000 to 100,000 times as acute as humans.
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“Let’s suppose they’re just 10,000 times better,” James Walker, former director of the Sensory Research Institute at Florida State University, said. “If you make the analogy to vision, what you and I can see at a third of a mile, a dog could see more than 3,000 miles away and still see as well.”
The differences between how dogs’ noses function compared to our own are great. When we inhale, we smell and breathe through the same airways within our nose. When dogs inhale, a fold of tissue just inside their nostril helps to separate these two functions.
“We found that when airflow enters the nose it splits into two different flow paths, one for olfaction and one for respiration,” Brent Craven, a bio-engineer at Pennsylvania State University, explained.
Some dog breeds have been said to smell a drop of blood spilled in water equivalent to 20 Olympic swimming pools. Others are able to detect chemicals diluted to one part per trillion, which is the equivalent of one pinch of salt on 10,000 tons of potato chips. These numbers are almost too incredible to believe, and they are between 10,000 and 100,000 times better than humans.
The first trace in the scientific literature relating to a dog smelling out cancer detection is found in a 1989 copy of The Lancet, a medical journal. Doctors published the case of a woman who came to the hospital explaining that her dog insisted on licking a mole on her leg. After experts examined the mole, they discovered that it was early-stage malignant melanoma. Hywel Williams and Andres Pembroke, two doctors who were responsible for advancing the idea that dogs could smell cancer, said the dog may have saved the woman’s life.
The story aroused the curiosity of Caroline M. Willis, director of research at the Amersham Hospital department of dermatology. In 2004, Williams launched the first practical study concerning dogs that could smell cancer. They were given simple discrimination tasks, detecting urine from bladder cancer patients as compared to normal urine.
“Our original intention was to train the dogs to detect skin cancer, but that was quite difficult to do,” she said. “So we decided to test for the abnormal chemicals released by bladder cancer into urine, which is easy to collect.”
The result was an overall success rate of 41 percent, with 22 successes in 54 tries. It is “a first, very tentative step into the whole area” of cancer detection by smell, Willis said.
[Image via Sean Gallup/Getty Images News]