Osteosarcoma is the most common type of bone cancer in dogs, and it’s something that every pet owner should be aware of. This aggressive disease usually develops in the long bones of the legs, but can also manifest in other bones of the body.
It’s a condition that mostly affects large and giant dog breeds, all starting in the osteoblasts. Osteoblasts are cells responsible for building and reshaping bone. Once osteosarcoma takes hold, it destroys healthy bone tissue and can spread to other nearby areas.
Bone cancer in dogs is a life-threatening condition, which means that quick action is needed. In this blog, we’ll discuss everything you need to know about osteosarcoma in dogs and how we can help.
What Causes Osteosarcoma in Dogs?
The exact causes of osteosarcoma in dogs aren’t fully understood, but several factors appear to increase a dog’s risk. This includes their genetics, size, and age.
While osteosarcoma can occur in any breed, it is far more common in large and giant breeds
Rottweilers
Irish Wolfhounds
Labrador Retrievers
Age is also another factor. Middle-aged and older breeds are observed to have higher cases, with ages about 6 to 8 years old. Despite this, the condition can still affect puppies.
Additionally, a dog with injuries and bone fractures that weren't able to heal properly is also at risk. Lastly, environmental influences like radiation, carcinogens, and harmful chemicals can increase the risk.
What Are the Symptoms of Osteosarcoma in Dogs?
The symptoms of osteosarcoma in dogs often consist of mobility issues.
Lameness and Limping. One of the most noticeable signs of canine osteosarcoma is difficulty moving. Your dog may start limping, which can become severe over time. This can be seen as favoring one leg when walking and a reluctance to use the affected leg.
Swelling. Dogs can also have significant swelling in the affected area. This is due to the aggressive nature of the cancer, as it grows and invades nearby tissue. The swelling can feel warm to the touch and is typically found on the front and back legs.
Pain. Because the condition destroys healthy bones, it is a very painful disease. Dogs may whimper and cry out when moving. They will be visibly uncomfortable.
Lethargy and Weakness. In addition to the pain, dogs will be lethargic and weak, preferring to lie down and rest rather than play.
Loss of Appetite and Weight Loss. Dogs will also lose interest in eating, even when given their favorite foods and treats.
Behavioral Changes. Dogs with osteosarcoma will be distraught, irritable, or aggressive because of the pain. They can also become more withdrawn and restless.
Pathological Fractures. The dog’s bones can also break even with minimal stress or trauma. These can be extremely painful.
How Is Osteosarcoma in Dogs Diagnosed?
Our vets will check for signs of osteosarcoma in your dog and assess its mobility. We’ll also check medical history and the record of recent injuries.
Imaging Tools
Next, we’ll use X-rays to see distinctive changes in your dog’s bone tissue. This can include:
Lytic lesions
Abnormal bone growth
Pathological fracture
Sunburst pattern of bone
For a more detailed look, we may make use of CT scans and MRIs to determine the exact size, location, and extent of the tumor. It's useful when we're considering surgery.
Laboratory Tests
We'll perform a biopsy to confirm the diagnosis by obtaining a sample of the bone for microscopic examination. Our vets can also use a fine-needle aspiration to collect cells for analysis. Blood tests can help us determine if your dog is fit for surgery.
Treatment for Osteosarcoma in Dogs
Our orthopedic surgeon, Dr. Sarabjit Singh, will be at the forefront of your dog's osteosarcoma treatment. The goal is to restore mobility and improve quality of life.
Surgical Intervention
Surgery is often the first step in treating osteosarcoma. This will be handled by our expert team of pet orthopedics. The two main surgical options are amputation and limb-sparing surgery.
Amputation
This is the most common treatment for osteosarcoma in dogs. Removing the affected limb eliminates the primary source of pain and can prevent the tumor from causing further damage to the bone. Most dogs adapt surprisingly well to life on three legs, even large dog breeds. It just takes time.
Limb-Sparing Surgery
In some cases, we can do a limb-sparing surgery to restore your dog’s overall mobility. It’s an option we recommend for large dogs and those with arthritis. It works by removing the part of the bone that’s diseased and placing a bone graft or metal implant to fill the gap.
Chemotherapy
Because canine osteosarcoma often metastasizes, chemotherapy is typically recommended following surgery to target cancer cells that may have spread. This method is generally well-tolerated in dogs, with fewer and milder side effects than in humans.
Radiation Therapy
For dogs that aren’t candidates for surgery, radiation therapy can be used to help manage your dog’s pain and slow the progression of the disease. This is a palliative treatment option designed to improve comfort and mobility rather than cure the cancer.
Radiation can also be used in combination with surgery or chemotherapy.
Pain Management
Managing pain is a common part of osteosarcoma treatment in dogs, regardless of the chosen approach. Non-steroidal anti-inflammatory drugs are often the most common choice for pain management. Opioids and gabapentin are also choices we consider.
Canine Osteosarcoma Prognosis
The prognosis for dogs with osteosarcoma is generally poor. Due to the aggressive nature of the cancer, dogs without treatment can survive for about 2 to 4 months. With treatment, outcomes can improve significantly.
Dogs that underwent amputation or limb-sparing surgery combined with chemotherapy typically live for 1 year, with around 20% of them reaching 2 years or more.
“When we care for our dogs, we not only add years to their life, but also life to their years.”
- Dr. Sarabjit Singh
Final Thoughts
Osteosarcoma in dogs is a serious and aggressive form of bone cancer that requires prompt attention and informed decision-making. It is most common in large and giant breed dogs, but just about any dog can be affected.
While the journey may be challenging, many dogs can experience a good quality of life with the right care and support.
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