How Osteosarcoma Affects Dogs: What Pet Parents Need to Know

Joelle Fenger, DVM

“Because osteosarcoma occurs in companion animals more often, it lends researchers the opportunity to access more data in a shorter period of time,” says Joelle Fenger, DVM, a medical oncologist and associate at Ethos Discovery, a nonprofit committed to improving the outcome for pets and humans who are living with cancer. “The ultimate goal is to find a cure — for dogs and humans alike. Our canine friends are helping us get there.”

The Frontline spoke with Dr. Fenger to understand current canine osteosarcoma research, osteosarcoma symptoms in dogs that pet parents should watch for, and what treatment options are available.

Are certain breeds affected by osteosarcoma more than others?

Yes. It turns out that large-breed dogs — specifically athletic breeds like Golden Retrievers, Labradors, German Shepherds, Greyhounds, Rottweilers, Boxers, and Irish Wolfhounds — are diagnosed with osteosarcoma more often. This tells us that there is probably a genetic or breed-related component to canine osteosarcoma.

Where does osteosarcoma affect dogs?

Osteosarcoma tumors arise in similar locations in both dogs and humans. That tends to be in the growth plate area, which is an area with a lot of rapidly dividing cells. In dogs, that usually means the long leg bones. Osteosarcoma also commonly spreads to the lungs, another similarity between humans and canines.

What are the first signs of osteosarcoma in dogs?

Because these tumors tend to cause a lot of bone breakdown, the earliest osteosarcoma symptoms are usually some form of lameness. For pet parents, if you notice your dog is limping or not using one of its legs, or if it is not able to exercise for as long as normal, have it evaluated by a veterinarian.

What are treatment options for canine osteosarcoma?

Surgery to remove the tumor remains the mainstay of treatment for these tumors. In dogs, because of the location of their tumors, a full limb amputation is often necessary. In most cases, dogs do amazingly well and adapt extremely fast to a tripod stance. Often, the dog is walking again within a week of surgery. Dogs have an amazing spirit and are incredibly resilient.

If the dog is not a good candidate for limb amputation, there are limb sparing procedures involving a bone graft that can preserve the limb. In terms of chemotherapy, there are options for dogs, just like there are for humans. Unfortunately, the side effects of chemo are similar too. Ultimately, treatment for osteosarcoma in dogs depends on the owner and the family’s goals.

Is there any new research on dogs and bone cancer that you’re excited about?

There is exciting research happening at Ethos Discovery. A clinical study called Minimally Invasive Metastasectomy in Canines (MIMIC), led by Chris Thomson, DVM, aims to provide a better option for osteosarcoma that has spread to the lungs. It replaces open chest surgery with a thoracoscopy, a minimally invasive surgical technique that uses tiny incisions in the chest wall to allow resection of lung nodules with the assistance of a magnified video camera. About 90% of dogs with osteosarcoma eventually develop tumors in the lungs, so this is promising research that could save a lot of lives.

The exciting part of studying osteosarcoma in both humans and dogs is the idea that hopefully by working together, we can move the needle. We need to help both kids and dogs with this disease.

What can pet parents do if their dog is diagnosed with bone cancer?

I recommend reaching out to the Veterinary Cancer Society. This national organization can provide information about treatment options, where you can go to get treatment, and information on clinical trials.