Dogs can detect cancer by smell, according to a new study in which trained dogs identified hemangiosarcoma, an aggressive blood-vessel cancer, in blood samples. Cancer is a leading cause of death in both humans and pets, and hemangiosarcoma is among the most lethal cancers affecting dogs.
In double-blinded tests, the dogs correctly identified cancer-positive samples about 70 percent of the time, a performance comparable to that of dogs trained to detect some human cancers. The results, published in The Veterinary Journal, indicate that the disease produces a distinct chemical scent profile, suggesting that the same scent-based mechanisms used in human cancer detection could one day help enable earlier diagnosis in both people and pets.
“This is very encouraging,” said coauthor Clara Wilson, in a press release. “Detecting cancer is incredibly hard — it’s a very complex smell.”
How Dogs Smell Cancer
Rather than detecting cancer itself, the dogs are responding to volatile organic compounds (VOCs), small chemical molecules released by biological processes in the body. These compounds are what humans perceive as smell, but dogs can sense them at far lower concentrations, allowing them to detect subtle changes in blood chemistry that accompany disease.
Previous research has shown that cancer can alter metabolic processes in ways that shift the mix of VOCs the body emits. In this study, the researchers set out to determine whether hemangiosarcoma produces a consistent enough chemical pattern to be detectable at all. Establishing the presence of such a scent signature was a necessary first step before considering whether technology could eventually be developed to replicate the dogs’ abilities.
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Testing a Cancer’s Scent Signature
The experiments involved five bio-detection dogs that had already been trained to recognize odor patterns associated with a range of other conditions, including both animal and human diseases. None of the hemangiosarcoma samples used in the study had been part of the dogs’ training.
During double-blinded trials, the dogs evaluated blood serum samples from dogs with confirmed hemangiosarcoma, dogs with non-cancerous illnesses, and healthy controls. Each dog assessed multiple matched sample sets across repeated trials, ensuring that performance could not be attributed to chance or familiarity with individual samples.
The tests were conducted using olfactometers, specialized devices designed to objectively record when a dog investigates a sample and for how long. When a dog correctly identified a target sample and remained focused on it for a set period, the system signaled success and delivered a reward.
Across all trials, the dogs identified hemangiosarcoma samples about 70 percent of the time, a level of accuracy comparable to results reported in studies where dogs were trained to detect certain human cancers. The finding suggests that the cancer produces a detectable chemical signal despite the inherent complexity of cancer-related odors.
Toward Earlier Detection
The results indicate that hemangiosarcoma does have a distinct scent profile, the central question the proof-of-concept study set out to answer. With that established, future research could focus on developing sensor-based tools capable of detecting the same chemical signals without relying on trained dogs. Such a test could eventually be incorporated into routine veterinary care, offering a way to flag the disease before it becomes life-threatening.
“It could flag a potential issue so that the owner could get further testing, such as ultrasound or CT scans,” Wilson said. “It could really help catch it early for these dogs where we’re just finding it far too late.”
Earlier detection could fundamentally change how veterinarians manage hemangiosarcoma, shifting treatment from crisis response to prevention.
“We could prevent the disease from spreading, because it’s the spread that’s really devastating,” said coauthor Cynthia M. Otto.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a recent study published in The Veterinary Journal: Trained dogs can detect the odor of hemangiosarcoma in canine blood samples