Jan 31, 2011 22:41 GMT  ·  By

Research has shown that dogs can identify bowel cancer within breath and stool samples with an extreme accuracy and even in the early stages of the disease.

These findings suggest that there are chemical compounds for specific cancers which travel through the body, this idea being a starting point to developing tests identifying the disease before it spreads even more.

The prodigious nose belongs to a specially trained Labrador retriever, that completed 74 sniff tests, every one consisting of five breath (100 to 200 ml) or stool samples (50 ml) at a time, only one of which was cancerous, over a several-month period.

The samples belonged to 48 people suffering from bowel cancer (at every stage of the disease), and to 258 volunteers without bowel cancer, or who had had cancer in the past.

Nearly half of the samples came from people with bowel polyps, a benign condition considered to be a precursor of bowel cancer, BMA reports.

Also, 6% of the breath samples and 1 in 10 stools samples came from people suffering from other gut problems, like ulcers, inflammatory bowel disease, diverticulitis and appendicitis.

The dog successfully identified which samples were cancerous and which weren't, in 33 out of 36 breath tests and in 37 out of 38 stool tests, with the highest success rate among samples of early stage disease.

In other words, there was a 95% overall accuracy in identifying breath tests and 98% accuracy for the stool test, which is far better than the conventional colonoscopy.

The dog even identified correctly samples from smokers or from other types of gut problems, which might have masked or interfered with other smells.

Adding the results of this research to those of prior studies, the authors concluded that there are specific identifiable odors of cancer cells, which travel through the body, and also that dogs are able to sniff out bladder, skin, lung, breast, ovarian and, of course, bowel cancers.

Obviously, using a dog to screen for cancers can be very impractical and expensive so the authors suggest that a sensor could be developed to identify the specific compounds.

They add that “early detection and early treatment are critical for the successful treatment of cancer and are excellent means for reducing both the economic burden and mortality [of bowel cancer].”

This research is published online in the journal Gut.