Bone Cancer (Osteosarcoma)
The most common primary bone tumour in dogs, typically affecting large and giant breeds.
What is Bone Cancer (Osteosarcoma)?
Osteosarcoma is an aggressive tumour of bone-forming cells, most often in the long bones of the limbs ('away from the elbow, toward the knee'). It causes severe bone pain and micrometastases to the lungs are usually present at diagnosis, even when X-rays look clear.
Common signs and symptoms
Signs vary between dogs and can be subtle at first. Watch for the following, especially if several appear together or persist for more than a few days:
- Persistent lameness that doesn't respond to rest or NSAIDs
- Firm, painful swelling on a long bone
- Reluctance to bear weight
- Sudden severe pain or a pathological fracture from minimal trauma
Risk factors
Certain dogs are more predisposed. Understanding risk helps you screen earlier and act sooner.
- Large and giant breeds: Great Dane, Rottweiler, Irish Wolfhound, Greyhound, Saint Bernard
- Middle-aged to older dogs (median around 7)
- Previous fracture site or long-standing bone infection
When to see a vet
Use this as general triage guidance, not a substitute for veterinary advice.
- Book a routine appointment if: your large-breed senior dog has a lameness that isn't resolving within 1–2 weeks.
- Seek urgent care if: sudden refusal to bear weight, obvious limb deformity, or severe pain.
Diagnosis and management
Diagnosis is via X-rays plus bone biopsy or aspirate, with chest imaging for staging. Standard of care combines amputation (which resolves pain immediately) with chemotherapy to slow metastasis, giving a median survival of around a year. Limb-sparing surgery, stereotactic radiation, and palliative pain protocols are alternatives for dogs who can't have amputation.