Cancer is the leading cause of death in dogs over ten years of age, and navigating treatment decisions while maintaining quality of life presents significant welfare challenges.
Cancer welfare decisions in dogs require balancing the duration of life against its quality — a calculation that can be genuinely difficult. Osteosarcoma causes bone pain so severe that many dogs cannot bear weight on the affected limb; amputation can eliminate this pain dramatically, with most dogs adapting quickly. Chemotherapy side effects are generally milder in dogs than humans, but some dogs experience significant nausea and fatigue. The key welfare obligation is to pursue treatment when it maintains or improves quality of life, and to recognize when palliative care and timely euthanasia better serve the animal than further aggressive treatment.