Osteosarcoma is the most common primary bone cancer in dogs, causing severe pain that is often undertreated, with welfare decisions around pain management and euthanasia timing being critically important.
Osteosarcoma causes relentless, severe bone pain that worsens progressively. Dogs may initially show subtle lameness but pain escalates to the point where limb use becomes impossible. The bone weakens as the tumor grows, risking pathological fracture - an acutely catastrophic and painful event. Pain management for osteosarcoma requires aggressive multimodal analgesia - NSAIDs, opioids, and adjuncts - to maintain quality of life. The most important welfare decision is recognizing when pain can no longer be adequately controlled and choosing humane euthanasia before suffering becomes intractable.