Cancer: Why Dogs are Critical in the Fight

There are countless stories of dogs waking their masters before a fire or an intruder causes serious harm. But there’s another way dogs are saving human lives.

In my very first blog post, I mentioned recent discoveries of dogs detecting cancer in humans. This amazing ability has been under study just in the last decade, and it’s not as mysterious as it might sound. We already know that dog’s olfactory glands have a highly developed sense of smell—some 200 million olfactory cells compared to a human being’s 5 million.

Researchers have now shown that dogs can be trained to sense the minute chemical-triggered changes in human breath and other body odors that occur once a cancer is growing inside. According to Psychology Today writer Mary Bates, the first study happened in 2004, when researchers at the Sensory Research Institute at Florida State University trained two dogs to detect melanoma tissue samples hidden on the skin of healthy volunteers.

photo: Borbala Fereczy

Since that time, there have been several more very successful studies. In 2011, GUT, a peer-reviewed research journal for gastroenterologists, published the result of a study done in Japan at St. Sugar Cancer Sniffing Dog Training Center the year earlier with a Labrador named Marine. The eight-year-old dog correctly detected colorectal cancer in more than 67 groups of people's breath and stools that scientists had collected. You can read the abstract of the study here, but basically the way it works is that the dog is rewarded when it chooses the cancerous scent in a control group of scents. Once trained, the dog will choose the cancerous scent whenever it finds it. 

Here's a question: What would you rather have, a colonoscopy or a simple breath and/or stool test? Kind of a no-brainer?

The results of the Japanese study showed that the dog was at least 95 percent as accurate as a colonoscopy when smelling breath samples, and 98 percent as accurate with stool samples. The dog’s sense of smell was also effective in detection of early-stage cancer, and could discern polyps from malignancies (which colonoscopies can’t).

But dogs are not only good at sniffing out colon and skin cancer. Canine scent tests have also been done with prostate, lung, breast, and ovarian cancers as well.

Beyond detection, dog researcher Stanley Coren, professor of psychology at the University of University of British Columbia and author of The Intelligence of Dogs, wrote in Psychology Today about some hard research done at Beth Israel Hospital in New York that confirms the value of therapy dogs in post-cancer treatment rehabilitation.

Both Bates’ and Stanley Coren’s attentiveness to these various studies make me wonder why more research is not being done to further the use of dogs in early cancer detection and post-treatment. Wouldn’t it be certainly cheaper, and potentially more effective, than psychotherapy or an MRI? Wouldn't it even further strengthen the human-dog bond?