How amazing are dogs? Not only are they man’s best friend providing steadfast companionship and guarding our homes and families, but now we know that they can also detect cancer. A recent study in the European Respiratory Journal found that dogs were able to detect lung cancer in humans by smelling their breath. They were accurate over 70% of the time. Researchers believe that there was a specific chemical compound that the dogs smelled in order to detect the cancer. Researchers believe that cancer cells give off different metabolic waste products than normal cells and that these have a different odor. These dogs were even able to discern the difference between people with lung cancer and people with chronic obstructive pulmonary disease (COPD).
Dogs can also detect other types of cancer through scent. One dog named Marine has been trained to detect colon cancer and can do so with 97% accuracy. She even beats the normal blood tests for cancer by a full 25%. Another test used dogs to detect bladder cancer and achieved over 40% accuracy. Researchers at the Pine Street Foundation in California trained five dogs to smell both breast cancer and lung cancer on a patient’s breath. The dogs had an accuracy rate between 88-99% and even navigated around odors like smoke.
And dogs can do more than just sniff for cancer. There are dogs that are trained to detect hypoglycemia in insulin-dependent diabetics. These dogs live with their owners as companions, but they are also there for medical purposed. Hypoglycemia can be a deadly situation for a diabetic and these dogs can alert their owners when their blood sugar levels are getting low, long before a crisis situation.
A dog’s ability to smell is one of its strongest features and is about 1,000 to 10,000 times stronger than a human’s sense of smell. On average humans have 5 million scent receptors, whereas dogs have hundreds of millions of them. When dogs smell something, they sniff and collect the air in a special chamber in their nose. Dogs are able to exhale while keeping this air in the chamber which allows the scent molecules to accumulate until there are enough of them for the dog to identify what it is. And dogs have another organ in their nasal cavity which helps them smell and taste. It’s called Jacobson’s organ and it means that they can not only smell the air, they can taste it too. If you’ve ever seen a dog almost grinning and holding his mouth in a somewhat open position, you may be witnessing the dog using his Jacobson’s organ. This pose is called a Flehman Reaction and is most often used when smelling the urine or sexual markers of other dogs.
And not only can dogs detect scents at a phenomenal rate, they can also remember them at an incredible rate. Their olfactory memories are fantastic and they can recall smells long after being exposed to them. They also gather information from the odors such as the health of an animal, sex, age and even what they ate for their last meal.
So what can we do with this new information? There are two ways to proceed. One, we can do more to train dogs to detect cancer. It’s a low cost, low invasive solution that can help with preliminary cancer screening. Second, researchers need to do more to figure out exactly how the dogs are doing it so that they can apply this knowledge to create machines and screening tests. But once again, nature in her wisdom has provided a natural solution to one of the greatest health issues facing people today.