Canine osteosarcoma — bone cancer — is an aggressive, painful malignancy that most commonly affects the limbs of large and giant breed dogs, requiring urgent pain management, difficult treatment decisions, and compassionate end-of-life planning.
Osteosarcoma causes severe bone pain that is often unrecognised or undertreated. Dogs are stoic and may mask pain until it becomes overwhelming. By the time a dog is clearly lame or reluctant to bear weight, significant bone destruction has usually already occurred. Urgent, high-dose pain management — NSAIDs, gabapentin, and often opioids — is a welfare necessity from the moment of diagnosis. The treatment decision is genuinely difficult: amputation plus chemotherapy offers meaningful survival benefit but involves surgical recovery and treatment side effects. Palliative care without amputation can maintain comfortable quality of life for some months with appropriate pain management but does not address the underlying progression. The welfare priority is ensuring that, whatever the owner chooses, the dog is never in undertreated pain.