January 31st, 2011
06:30 PM ET
A dog in Japan is able to detect bowel cancer using its sense of smell, according to new research.
"We used the excellent ability of dogs to distinguish between different scents to examine whether odor materials can be used in the diagnosis of colorectal cancer," writes Dr. Hideto Sonodo in his study published this week in the medical journal Gut.
In other studies, dogs have been able to distinguish the smell of bladder cancer, lung cancer, and breast cancer.
In the new study, researchers collected breath and stool samples from patients with colorectal cancer. They placed one cancer sample and four non-cancer samples into light blue wooden storage containers, and in a series of "sniff" tests, commanded a black Labrador retriever to "Search!" for the container that held the cancer sample.
The dog sniffed out the cancer sample in 33 out of 36 breath tests and in 37 out of 38 stool tests. That's almost as accurate as a colonoscopy test for colorectal cancer.
In some cases the samples had come from patients with early stages of bowel cancer, suggesting the chemical compounds that give colorectal cancer its smell may be present early in the course of the disease.
Doctors currently use a fecal occult blood test to screen for cancer at early stages, but the study authors note the test is accurate in only one in 10 cases. An inexpensive, more accurate test to detect bowel cancer early could help in the fight against the disease, but don't expect dogs to take the place of colorectal cancer tests.
"It may be difficult to introduce canine scent judgment into clinical practice owing to the expense and time required for the dog trainer and for dog education," notes Sonodo.
Instead, if the specific chemicals that produce the smell of colorectal cancer are identified, Sonodo says, a sensor could one day be substituted for the dog.
The dog learned how to search for the disease at the St. Sugar Cancer Sniffing Dog Training Center in Chiba, Japan.
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