Cancer is a leading cause of death in older dogs. Modern veterinary oncology offers treatment options that can extend good-quality life, but quality-of-life assessment must guide all decisions.
Canine cancer welfare management requires honest assessment of treatment goals: is the aim cure, disease remission for extended good-quality life, or palliation of symptoms? Different cancers warrant different approaches — lymphoma often responds well to chemotherapy with minimal side effects and good quality of life during treatment; osteosarcoma causes severe pain that requires aggressive management even with amputation. Dogs generally do not anticipate their prognosis, making present quality of life the most ethical guide for treatment decisions. Chemotherapy in dogs is typically dosed to maintain quality of life rather than achieve maximum tumor kill — unlike human oncology. Quality-of-life assessment scales help owners and veterinarians make humane decisions about when treatment burden outweighs benefit. Veterinary oncology represents one of the most significant advances in companion animal welfare of the past 30 years.