It turns out that dogs may be much more than just furry companions. New research suggests that canines can detect bowel cancer, even in its early stages, with a remarkable degree of accuracy.
A study published on Monday in the journal Gut found that a specially trained Labrador retriever was able to identify the presence of cancer in breath and stool samples 95 and 98 per cent of the time, respectively.
The findings help to build on an emerging area of research that is focused on the relationship between dogs and their ability to sniff out cancer.
Previous studies have found that dogs are able to detect cancer in humans by smelling their breath, urine or other samples. Although they do not yet understand the mechanism behind it, researchers believe that dogs, which have an extremely powerful sense of smell, are able to identify the scent of chemical compounds associated with cancer.
For instance, a 2006 study published in the journal Integrative Cancer Therapies determined that dogs with only a few weeks of training could accurately differentiate between breath samples of patients with lung and breast cancer and those of healthy subjects.
In the new study, researchers in Japan used breath and stool samples from 48 people with confirmed bowel cancer and 258 healthy volunteers. A trained Labrador retriever correctly identified cancerous samples in 33 out of 36 breath tests and 37 out of 38 stool tests. The highest detection rates were with samples taken from individuals with early stages of the disease.
The researchers noted that samples taken from smokers or those with other problems related to the gut, such as ulcers or inflammatory bowel disease, did not seem to interfere with the dog's ability to correctly detect cancerous samples.
While the findings are preliminary and cannot yet be applied in patient settings, they suggest that there may be a way one day to use the sniffing powers of dogs to help detect cancer early. "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]" the study's authors said in a statement.
The idea of early detection for bowel cancer is intriguing because many individuals avoid getting screened for the disease because of the unpleasant nature of colonoscopies. Making it easier, and less invasive, to be screened for the disease could potentially help in the quest toward early detection and treatment.
Given the impracticality of using dogs in health-care settings, it's more likely that sophisticated machines would be developed and used instead of animals. "Nobody's ever going to do it with dogs," said Gary Beauchamp, director of the Monell Chemical Senses Center in Philadelphia, an independent institute dedicated to taste and smell research. "Would you go into a hospital and have a dog come up to sniff you to diagnose you?"
The challenge going forward, according to Dr. Beauchamp, will be figuring out how dogs are able to identify cancerous samples and try to use that knowledge to create a machine. But even if that can be accomplished, scent detection will not replace other important diagnostic tools, he said.
"I think it's going to happen," Dr. Beauchamp said. "It's not the answer to everything. It will be one of the tools used."