The science behind dogs' exceptional cancer detection capabilities

Dogs have long been celebrated for their extraordinary sense of smell. Whether it’s used to track missing persons or to detect explosives and narcotics, their abilities far surpass humans. But what makes dogs so effective in detecting subtle odor signals, particularly those associated with diseases like cancer? The answer lies in their unique biology, sophisticated sniffing mechanisms and highly trainable nature.

At SpotitEarly, we’re harnessing these incredible characteristics to transform early cancer detection, using dogs as the first line of analysis for all incoming samples. This post considers the science and behavior that make dogs such exceptional scent detectors and the meticulous training program that prepares them for this life-saving work.

A natural wonder

Dogs are equipped with an unmatched sense of smell – one that’s designed to detect even the faintest odor signals. Their biological design is what sets them apart.

Everything starts with the structure of a dog’s nose, which is fundamentally different from that of a human. The olfactory epithelium, a specialized tissue responsible for detecting odors, is vastly more developed in dogs, offering a surface area of around 150 square centimeters — compared to just 5 square centimeters in humans. Packed into this space are approximately 300 million olfactory receptors, far exceeding the human count of 5–6 million.

The olfactory cortex in dogs also plays a critical role in their ability to detect and analyze smell. This region of the brain, responsible for processing scent information, is significantly larger and more complex in dogs compared to humans. It enables them to interpret subtle differences in odor profiles, distinguishing disease-related volatile organic compounds (VOCs) from background scents. As Dr. Irit Gazit, Director of Canine Applied Research at SpotitEarly explains, “The relative size of a dog’s olfactory cortex is very large and occupies 30% of the dog’s cortex. This allows them to combine scent data with other sensory inputs like vision and hearing for unparalleled accuracy.”

This is also supported by the unique way that dogs sniff. When this happens, dogs are not just breathing – they’re actively directing particles to their olfactory receptors. In fact, dogs can sniff 5 to 10 times per second, which creates a constant flow of air across their olfactory epithelium. This rapid sniffing not only increases the concentration of odors, but also allows dogs to analyze scents in “real time”, helping them continuously update a smell map of their environment.

These unique capabilities help make dogs indispensable in medical diagnostics, particularly when detecting diseases through their scent profiles.

Behavioral traits

While their biology gives them the tools, it’s the dogs’ behavior profile and training that allow them to excel as disease detectors. At SpotitEarly, we use labrador retrievers and beagles, which have been trained by our experts almost from birth. The choice of breed is deliberate according to Gazit: “We closely look at the dog’s characteristics. In particular, we’re looking for dogs that have the motivation to work and that are fast learners.”

The training process at SpotitEarly is meticulously designed to leverage dogs’ natural abilities while ensuring consistency and precision. We typically focus on three key elements to make dogs successful in their work.

Selective focus: Dogs are naturally curious creatures, but through training, they can learn to filter out irrelevant smells and focus solely on specific VOCs. SpotitEarly uses positive reinforcement to associate cancer odors with rewards like food or play. As Gazit notes, “We link the cancer odor with a reward, creating a strong motivation for the dog to search and identify.”
Memory and consistency: Once trained, dogs demonstrate an impressive ability to remember scent patterns over time. This consistency ensures reliable performance even when they’re reviewing many different samples. Regular retraining and practice sessions help maintain their sharpness, ensuring that their responses remain accurate and dependable. “The dogs’ ability to differentiate between odor targets and background is unmatched,” says Gazit. “They excel at identifying the common denominator in cancer odors, even when individual samples vary.”
Response mechanisms: When a trained dog detects a disease-related scent, it signals its findings through a pre-taught behavior. At SpotitEarly we use different high levels of trained dog behavior to signal odor target identification. These responses are validated through multiple trials, ensuring that the detection is not a one-off event but a reliable result.

Real-world application at SpotitEarly

SpotitEarly leverages dogs’ natural abilities to detect VOCs in breath samples. With sensitivity and specificity exceeding 90%, our canine partners are integral to our diagnostic process. Once the dogs complete their analysis, their findings are validated by LUCID, our proprietary AI and technology platform, to add another layer of precision and accuracy.

As Dr. Reef Einoch Amor, Director of Chemical Analysis, explains: “Dogs can analyze hundreds of samples in a single day. Their ability to work quickly and accurately makes them an essential part of our diagnostic process.”

The integration of canine detection with AI also helps ensure scalability and standardization, allowing SpotitEarly to replicate its processes globally. “We’ve designed our facilities to be easily replicated anywhere in the world,” says Amor. “This means that more people can benefit from our early cancer detection products.”

While SpotitEarly currently focuses on cancer detection, dogs’ olfactory skills have already been applied in other medical fields. For example, they have been trained to detect However, the potential of canine medical scent detection has already been highlighted for the detection of epilectic seizures, low blood sugar in diabetics, malaria and infections such as COVID-19. These advances highlight the versatility and potential of canine olfaction in healthcare.

At SpotitEarly, we’re proud to harness these abilities alongside our own cutting-edge technology to develop life-saving diagnostic tools. As Amor aptly puts it: “If you want to detect cancer by its smell, then dogs are the very best way to do it.“

Together, we’re proving that when natural intelligence and artificial intelligence meet, the results can change lives.

Learn more about how our dogs help SpotitEarly to transform early cancer detection at SpotitEarly.com.