Hemangiosarcoma is a cancer of the cells that line a dog’s blood vessels. It grows quietly. Many owners learn their dog has it only after an apparently healthy animal collapses, and by then the disease has usually spread.
Researchers at the University of Pennsylvania School of Veterinary Medicine wanted to know whether other dogs could smell it first. According to a study published in The Veterinary Journal and announced by Penn in January 2026, they can, at least in a lab.
Five noses, 423 trials
The study used five bio-detection dogs from the Penn Vet Working Dog Center. All five had already been trained on odors linked to chronic wasting disease, PTSD, and human ovarian and pancreatic cancer.
The dogs worked an automated line-up that presented blood serum samples from three groups: dogs with confirmed hemangiosarcoma, dogs with other diseases, and healthy dogs. Every sample was new to them, and the tests were double-blind, so neither the dogs nor their handlers knew which sample was which.
Across 423 blinded trials, the dogs were 70 percent accurate overall. They alerted on hemangiosarcoma samples 73.4 percent of the time, compared with 21.3 percent for samples from dogs with other diseases and 17.1 percent for healthy dogs. Put another way, their odds of flagging a cancer sample were about ten times higher than for a sample from another sick dog, and about 13 times higher than for a healthy one.
“We’re picking up on volatile organic compounds every time we smell something,” said Clara Wilson, a postdoctoral research fellow at the Working Dog Center. “The dogs have an ability to detect them at much lower levels than we can.”
Toward a routine test
The dogs are not meant to become the diagnostic tool. The goal is to identify what they are smelling so it can be turned into a lab or machine test that could be part of a yearly checkup. “It could flag a potential issue so the owner could get further testing,” Wilson said.
Penn notes that between one-third and one-half of all dogs will develop cancer during their lifetime. Cynthia M. Otto, professor of working dog sciences and sports medicine, explained why early warning matters with this one in particular: “We could prevent the disease from spreading, because it’s the spread that’s really devastating.”
The authors say the number of hemangiosarcoma samples in the study was small and more work is needed. The research was funded in part by the AKC Canine Health Foundation, Morris Animal Foundation and the Golden Retriever Foundation.
Sources
- Penn Today, Sniffing out cancer: Trained dogs can detect hemangiosarcoma by scent (Jan. 15, 2026)
- The Veterinary Journal, Trained dogs can detect the odor of hemangiosarcoma in canine blood samples (Wilson et al., 2026)
