When Maureen Burns began noticing strange behaviors in her dog, Max, she feared that he was dying. “The odd signs were when he would come up and touch my breast with his nose, and back off so desperately unhappy with such a sad look in his eyes,” Burns said in a video uploaded by BBC Earth.
Burns had a lump in her breast but her mammograms had shown no detection of cancer, so she was not worried. However, as her dog’s strange behavior continued, she got another mammogram, which once again was clean. It wasn’t until she underwent a surgical biopsy that doctors discovered that Burns had breast cancer.
Though seemingly shocking, Burns’ story is not uncommon. There are countless stories of dogs behaving strangely, such as poking or pushing a certain spot of the owner’s body, only for the owner to discover they have cancer. The malignant cancer tissue gives off a subtle scent that many believe is the key to the future of early cancer detection.
These stories have arisen the curiosity of the scientific community and fostered the creation of the organization InSitu, which is devoted to training dogs who can detect cancer by smell.
So far, the institution’s research proves promising and claims to have 99 percent sensitive and 88 percent specific accuracy levels in the detection of lung and breast cancer.
At the Penn Vet Working Dog Center, dogs are led around a table of 12 tiny arms holding samples of blood plasma, in which only one contains a drop of cancerous tissue. The center uses positive reinforcement and gives toys and treats to the canines if they guess correctly.
The dogs selected for training are often hunting hounds and police dogs, both of which have a strong sense of smell that has been refined by generations of selective breeding. The dogs are also selected based on personality; while those trained as search and rescue dogs must be tireless hunters, unwilling to give up on a scent, the best cancer-detection dogs tend to be more precise and introverted.
The response of this research in the scientific community has been mixed. Charlie Johnson, a professor at University of Pennsylvania, is currently developing an “electronic nose” that can isolate compounds that the dogs are sniffing out. Others scientists remain skeptical, not believing that canines will be able to detect cancer in its most vulnerable and treatable stages.
Cancer claims more than half a million lives a year, but with new early detection methods, the hope is that this number can be reduced by one-third.