These Dog Breeds Are More Likely to Develop a Deadly Tumor, New Study Says

Few things are more heartbreaking than finding out that your dog has a tumor — but with early intervention, it isn’t always a death sentence. The chances of developing a life-threatening condition may seem largely unpredictable, but a new study published last week in PLOS One has found that certain dog breeds are more predisposed to a rare and potentially deadly adrenal tumor known as phaeochromocytoma (dubbed PCC for short). While PCC tumors are not always cancerous, they can disrupt hormone function and cause potentially deadly health problems regardless — so knowing your pup’s risk level is vital.

After analyzing the veterinary records of over two million dogs in the United Kingdom, the researchers found that Soft-Coated Wheaten Terriers, German Pointers, and Miniature Schnauzers were more likely to be diagnosed with the adrenal tumors. Specifically, the Soft-Coated Wheaten Terrier was found to be 30.9 times more likely to develop PCC than other breeds. Also at higher risk, German Pointers and Miniature Schnauzers are 11 and 4.7 times more likely to be diagnosed. English Cocker Spaniels and Labrador Retrievers, on the other hand, were less likely to develop the tumors.

Generally, Terriers breeds were more prone to PCC, as Terriers are more predisposed to all endocrine tumors. Other risk factors for PCC include being a neutered male and being between the ages of nine and 15; younger dogs were less likely to develop the tumors.

PCC can manifest in both dogs and humans and develops in the innermost part of the adrenal glands. It’s characterized by an overproduction of hormones, particularly those involved in the “fight or flight” response. This leads to overstimulation of the cardiac system, which then can lead to further complications. 

In both humans and dogs, PCC is incredibly underdiagnosed. But the new study also showed that the risk of PCC diagnosis is up to 25 times higher in dogs than in humans. The tumors are understudied in dogs because the symptoms are very easily mistaken for other conditions. Signs of PCC include hypertension, collapse, increased heart rate, and irregular heart rate — which all could point to more common cardiovascular or neurological conditions. 

According to the paper, there have been many instances when the tumors were only detected while the abdominal area was being assessed for another problem. In fact, nearly half of all PCC cases are asymptomatic and tumors are usually not detected until after a dog’s death. Early detection is very good for the prognosis; once the tumor is removed during surgery, many dogs can live for years after. If the tumor isn’t removed, PCC is often fatal. With this in mind, knowing a particular dog is predisposed to this cancer could allow pet parents and veterinarians alike to be able to detect it early on and potentially save the dog’s life. 

“Although a rare diagnosis in dogs at a population level, phaeochromocytoma carries huge welfare impacts for those individual dogs diagnosed and their owners,” study co-author Dr. Dan O’Neill, a professor of companion animal epidemiology at the Royal Veterinary College, said in a statement. “Owners of predisposed breeds such as Soft-Coated Wheaten Terrier, German Pointer and Miniature Schnauzer and veterinary surgeons now have the power of big data as an advance warning system on the increased risk here and so hopefully achieve earlier diagnosis and better outcomes.”