Horse Cancer and Quality of Life

Cancer is increasingly diagnosed in companion horses as diagnostic capabilities improve and populations age. Managing cancer welfare requires evidence-based assessment of quality of life.

Key Facts

Melanoma is the most common cancer in grey horses, affecting over 80% of grey horses over 15 years of age
Squamous cell carcinoma around the eye, sheath, and vulva is the second most common equine cancer
Lymphoma presents variably in horses; some cases are manageable while others progress rapidly with poor prognosis
Pain assessment tools for horses with cancer use behavioural indicators including the Horse Grimace Scale
Palliative care including pain management and quality of life optimisation is increasingly available through equine oncology specialists
Equine euthanasia when quality of life is compromised by cancer is a welfare-positive decision that requires owner preparation

Welfare Considerations

Equine cancer welfare requires honest assessment of quality of life alongside active treatment consideration. Unlike companion dogs and cats, horses cannot receive the same range of oncological treatments, making quality of life assessment and palliative care particularly important. Horses with advanced cancer may continue to appear functional while experiencing significant pain that behavioural tools can help identify. Supporting horse owners through cancer diagnoses and end-of-life decisions requires both clinical expertise and emotional intelligence from veterinary teams.

What You Can Do

Monitor grey horses for melanoma development from an early age and discuss management with your vet
Learn to use equine quality of life assessment tools for horses with chronic conditions including cancer
Seek referral to equine oncology specialists for complex cancer cases
Have honest conversations with your vet about prognosis and quality of life trajectories
Support equine veterinary oncology research to improve treatment options and quality of life management