(FUKUOKA, Japan) -- With a little training, a dog can learn to heel. But a new study adds to growing evidence that man's best friend can also learn to heal by detecting invisible signs of disease.
Marine, a specially-trained 8-year-old black Labrador retriever, detected colorectal cancer 91 percent of the time when sniffing patients' breath and 97 percent of the time when sniffing stool, according to a study published Jan. 31 in the British journal Gut.
She even beat the fecal occult blood test, the most economic and non-invasive screening for colorectal cancer, which positively predicts the presence of cancer only 10 percent of the time, according to lead author Dr. Hideto Sonoda, from Fukuoka Dental College Hospital in Japan, and colleagues.
This is not the first time dogs have successfully sniffed out malignancies. The phenomenon has already been reported in skin, bladder, lung, breast and ovarian cancers.
"We shouldn't be shocked by this," said Dr. Marty Becker, a veterinarian at the North Idaho Animal Hospital and author of The Healing Power of Pets. "We know dogs can detect accelerants, explosives, mold, peanuts -- even counterfeit CDs."
It's estimated that a dog's sense of smell is up to one million times better than that of a human, depending on the breed.
"It's like having an NFL stadium filled with yellow balls and one red ball," Becker said. "That's the concentration of scent a trained dog could find."
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