Bone cancer in dogs is relatively common compared to humans. More than 10,000 cases of canine osteosarcoma, the most frequent type of bone cancer in dogs, are diagnosed in the United States every year. Your dog’s risk depends heavily on breed, size, and age, with large and giant breeds facing dramatically higher odds than smaller dogs.
Overall Incidence
Osteosarcoma accounts for roughly 85% of all bone tumors in dogs, making it by far the dominant type. The 10,000-plus annual U.S. cases represent a significant share of canine cancers overall. For context, the human equivalent is only about 1,000 cases per year in a population that vastly outnumbers the dog population. Dogs develop osteosarcoma at a rate roughly 10 times higher than people do.
Not every dog faces the same level of risk. The single biggest factor is body size. Dogs over 80 pounds carry substantially higher odds, and the risk climbs further in giant breeds weighing over 100 pounds. Small dogs can develop bone cancer, but it’s uncommon enough that most veterinarians treat it as a large-breed concern.
Breeds at Highest Risk
A large UK veterinary study quantified just how uneven the risk is across breeds. Compared to mixed-breed dogs, Scottish Deerhounds had 118 times the odds of developing osteosarcoma. Leonbergers had about 56 times the risk, Great Danes 34 times, and Rottweilers 27 times. Greyhounds also ranked high, with an annual prevalence of 0.62%. Eleven breeds in total showed significantly increased odds compared to crossbreds.
A Norwegian population study found similar patterns. Irish Wolfhounds had an incidence rate of 126 cases per 10,000 dog-years at risk, while Leonbergers came in at 72 per 10,000. Compare that to Labrador Retrievers at just 2 per 10,000. That means an Irish Wolfhound is roughly 60 times more likely to develop a primary bone tumor than a Lab over the same period.
Other commonly affected breeds include Saint Bernards, Doberman Pinschers, Golden Retrievers, and German Shepherds. If you own a large or giant breed, bone cancer is one of the more important health risks to be aware of.
Age and Sex Patterns
Most dogs are diagnosed with osteosarcoma between the ages of 7 and 10, though it can appear in younger dogs as well. Some researchers have noted a smaller spike in cases around age 2, particularly in giant breeds, suggesting a possible link to rapid bone growth during adolescence. Males are affected slightly more often than females, though the difference isn’t dramatic enough to change how owners should approach screening.
Where Bone Cancer Develops
About 75% of canine osteosarcoma occurs in the limbs. The two most common specific locations are the lower front leg (near the wrist) and the upper front leg (near the shoulder). The hind legs are affected less frequently, with the area just above the knee being the most common rear-limb site. The remaining 25% of cases occur in the skull, spine, ribs, or pelvis.
Tumors in the limbs tend to cause more obvious symptoms because they interfere with movement. Tumors in the spine or skull can be harder to detect early and sometimes present with vague signs like facial swelling or difficulty eating rather than the more recognizable limping pattern.
Signs to Watch For
The first thing most owners notice is limping. Osteosarcoma is a painful cancer, and lameness that doesn’t resolve with rest or anti-inflammatory medication is the hallmark symptom. You might also see firm swelling on a leg, particularly around a joint. The swelling is typically hard rather than soft and doesn’t move when you press on it.
Over time, the affected limb may lose muscle mass as your dog shifts weight away from it. Some dogs stop eating, become reluctant to play, or show personality changes simply because they’re in chronic pain. These less specific signs are easy to attribute to aging, which is one reason bone cancer often isn’t caught until the tumor is fairly advanced. In some cases, the first sign is a sudden fracture from a bone weakened by the tumor.
How It’s Diagnosed
If your vet suspects bone cancer based on a physical exam and your dog’s symptoms, the first step is typically an X-ray of the affected area. Osteosarcoma creates a distinctive “moth-eaten” pattern of bone destruction that’s often visible on standard radiographs. A fine needle biopsy helps confirm the tumor type.
Because osteosarcoma spreads aggressively to the lungs, a chest X-ray is a standard part of the workup. At the time of diagnosis, visible lung metastases are present in roughly 10 to 15% of dogs, though microscopic spread has likely already occurred in the vast majority. If limb-sparing surgery is being considered, a CT scan or MRI may also be needed to map the extent of the tumor.
Survival and Treatment Options
Without treatment, most dogs with osteosarcoma survive only one to two months after diagnosis, largely because the pain becomes unmanageable. Amputation alone extends the median survival to about 5 months. When amputation is combined with chemotherapy, the median survival time increases to approximately one year, and some dogs live well beyond that. A study of long-term survivors found that with aggressive treatment, a meaningful percentage of dogs lived more than a year past diagnosis.
Most dogs adapt to life on three legs surprisingly well, particularly when the pain of the cancerous limb is removed. For dogs that aren’t good candidates for amputation (due to arthritis in other limbs or other health issues), limb-sparing surgery may be an option at specialized veterinary centers. This approach removes the tumor while preserving the leg, though it carries a higher complication rate.
Newer approaches are in early stages of testing. Immunotherapy trials, including inhaled treatments targeting lung metastases, have shown some promise. One clinical trial at UC Davis found a clinical benefit rate of about 30 to 39% in dogs with metastatic disease, though response rates remain modest. These treatments are currently available only through clinical trials at veterinary teaching hospitals.
Cost of Treatment
Treatment costs vary widely depending on your location, the complexity of surgery, and the chemotherapy protocol your veterinarian recommends. Amputation surgery generally starts around $500 and can run significantly higher depending on the facility and your dog’s size. Chemotherapy typically costs between $150 and $600 per dose, with total treatment courses ranging from $3,000 to $10,000 or more over several months. Palliative care (pain management without surgery) is less expensive but focuses on comfort rather than extending life.
Pet insurance can offset these costs if the policy was in place before diagnosis, but most policies exclude pre-existing conditions. Financing options like CareCredit are commonly used at veterinary oncology practices.