When a dog has a mass on its spleen, it puts veterinarians and owners in a difficult position. Current tools like ultrasound can’t definitively tell a deadly hemangiosarcoma from a benign mass without taking a tissue sample through surgery. This leaves families facing a tough choice: proceed with a major operation that might be unnecessary, or risk a dangerous delay in treating a fast-moving cancer. HSA is especially challenging because it often shows few signs until a dog suffers an acute collapse from internal bleeding.
A recent study investigated a novel, completely non-invasive approach: using the powerful sense of smell of trained dogs to detect HSA from a simple blood sample.
Researchers collected blood serum from dogs with confirmed HSA, dogs with other non-cancerous illnesses, and healthy dogs. These samples were sourced from veterinary biobanks and university hospitals. Dogs were then trained using positive reinforcement to recognize the scent of HSA serum, practicing on a specialized olfactometer that presented the samples blindly.
In final double-blind testing, the dogs correctly identified serum from dogs with HSA with 70% sensitivity and 70% specificity. This level of accuracy provides strong proof-of-concept that HSA gives off a distinct odor signature in blood that dogs can detect.
The odor is believed to come from volatile organic compounds (VOCs)—tiny chemicals released into the bloodstream by the tumor’s unique metabolism. By including samples from dogs with other illnesses, the study showed the dogs were likely smelling something specific to the cancer, not just a general sign of sickness.
This finding is a promising step toward a future diagnostic test. While trained dogs themselves are not a practical clinical tool, they have successfully demonstrated that a detectable biomarker exists. The next step is for scientists to identify the exact chemicals involved, with the goal of creating a scalable lab test or electronic sensor.
The study does note important limitations. It was relatively small, and the test was designed to differentiate HSA from other diseases, not specifically from benign splenic masses. Larger validation studies are needed.
The confirmation that dogs can smell HSA in blood is a significant step toward a much-needed, non-surgical test. If this odor signature can be translated into a common diagnostic tool, it could one day help veterinarians catch this aggressive cancer earlier and make more confident treatment decisions.
