Cancer is the leading cause of death in dogs over ten years old. Advances in veterinary oncology offer more treatment options than ever before, but the welfare focus must always remain on quality of life rather than length of survival.
Canine cancer welfare requires keeping quality of life at the centre of every treatment decision. Unlike human oncology, where aggressive treatment is often pursued even with significant side effects, veterinary oncology is explicitly oriented toward maintaining the dog's comfort and enjoyment of life. Chemotherapy protocols used in dogs cause far fewer severe side effects than equivalent human doses — they are designed to control, not cure at any cost. The primary welfare risks in cancer management are undertreated pain — particularly in osteosarcoma, where pain is often severe and requires multimodal management — and the prolongation of life beyond the point where quality is acceptable. Regular quality-of-life assessment using validated tools (HHHHHMM scale or similar) helps owners and vets recognise when the balance has shifted. The decision to pursue palliative care only, or to euthanise, is a welfare-centred choice that should never be delayed when quality of life is no longer maintainable.