Doggie Detectives Sniff Out Cancer

Cancer detecting canines are here.  Dogs trained to sniff out prostate, breast and lung cancer did very well in two recent studies.  One presented earlier this month at a meeting of the American Urological Association found that a particular breed, Belgian Malinois shepherd dogs, can be trained to detect prostate cancer, and they do it through their incredible sense of smell.  Another study in 2006 showed trained dogs sniffed out breast and lung cancer quite accurately.  Well I'll be.

The prostate cancer study was conducted at Paris's Hospital Tenon, and looked at dogs trained to distinguish between the smell of urine from men with prostate cancer and those without.  At the end of the study the dogs correctly identified 63 of 66 samples.

Dogs have a much stronger sense of smell than do humans (100,000 times stronger) and can detect subtle changes in odor that go unnoticed by man.  Dogs' olfactory sense is so good that they've been used by police for years to sniff out drugs, explosives and escaped prisoners.

It is believed that cancer cells, particularly of the prostate, may give off distinct odors; and the molecules responsible is what has scientists most interested.  Lead researcher Jean-Nicolas Cornu concluded that the dogs "are certainly recognizing the odor of a molecule that is produced by cancer cells."

Some critics think the phenomenon might be due to subconscious cues the researchers give off leading the dogs to pick up which samples were cancerous and which were not.  This was the case with a horse named Hans, in early 1900s Germany, which was claimed to be able to solve math problems, read and understand German, and perform other uncanny tricks.  With more investigation, though, it was found that Hans was indeed picking up on subconscious cues from his trainers.  This led to the term being named in research circles as the "Clever Hans effect."

The study's authors acknowledge that more investigation needs to be done, but they are optimistic.  If it turns out that they are right and dogs are picking up the distinct smells of cancer, the hounds can be used as an screening tool for cancer, much more accurate than the current blood tests used today.

Well, it's interesting to me that the sense of smell is being used to detect something humans can't on their own.  Olfaction is a primitive sense that developed along with the limbic system.  Smell evolved as a survival mechanism to warn living things of eminent danger, whether a poisonous plant or an approaching predator.  Many organisms have better smell than humans, so why not recruit one to help?  Heck, dogs do just about everything else, why not don a white coat and participate in some research?  Now, that's a good boy.