Atlantic Veterinary College testing new drug for heart tumors in dogs

The Atlantic Veterinary College is testing a new type of drug on dogs to see if it will help shrink cancerous heart tumours.

Propranolol is typically used as a heart medication for humans and to treat vascular tumours in children. Abigail Martin, the co-lead investigator and a second-year cardiology resident at the college, said there's promising indications that the drug could also help canines.

"This medication has shown to actually shrink or completely get rid of these tumours in children," Martin told CBC News.

"So our thought process is that if it works for kids, then we're hoping to look to see if it works the same for dogs."

Propranolol is also used to treat a few other conditions like high blood pressure and abnormal heart rhythms.

But it's the similarities between vascular tumours in kids and canine heart tumours that make researchers think it will be effective.

"They actually have very similar mechanisms on how they are grown," Martin said.

"Obviously one being more malignant and cancerous, the other one being more benign, but research has really shown promise to say maybe we should look into this a little bit more."

Tumours common, but hard to treat

Martin said heart tumours in dogs are "surprisingly more common" than she expected when she first got into veterinary medicine.

"The first few years I was a bit shocked to see how many patients I would see come in on emergency with the diagnosis of the fluid around their heart and then finding out that they have these heart tumours," she said.

"It's not something that is rare."

But many dogs don't present with symptoms until the tumour has become a major issue.

"A lot of the time dogs can have these tumours and never know," Martin said. "So they never show any signs of illness or they go on living their normal lives until it becomes an emergency."

At that point, there aren't many treatment options other than palliative care to make the dogs more comfortable.

And the treatment options that do exist, like surgery or chemotherapy, are prohibitively expensive.

"The encouraging aspect about propranolol for these patients is that it's actually a fairly cheap medication," Martin said.

'We're happy to see them'

Because dogs with heart tumours usually don't present with symptoms early on, Martin said it might be hard to find participants for the study.

"We know that these cases are being seen around all clinics, emergency clinics and primary care clinics as well," she said. "If owners are interested in pursuing ... alternative options for these patients, then we're happy to see them."

The college is encouraging dog owners who think their pets might benefit from the study to consult with their veterinarian. If they're enrolled, the dogs will receive the trial medication orally at home for one month, with ongoing monitoring by the AVC's veterinary specialists.

This study will be the first time propranolol is used specifically to treat canine heart tumours, said Martin, but if it shows promising results it could also be tested for treatment of other types of cancer.