Skin cancers are among the most common tumours in dogs, with several types — mast cell tumours, squamous cell carcinoma, and melanoma — causing significant welfare harm and requiring prompt veterinary intervention.
Skin cancer welfare in dogs spans from the relative welfare burden of surgical treatment with good prognosis outcomes to the profound suffering of aggressive tumours like histiocytic sarcoma that are frequently fatal within weeks of diagnosis. Mast cell tumours occupy a wide spectrum: low-grade MCTs treated with adequate surgery have excellent prognosis and minimal welfare impact beyond the procedure itself; high-grade MCTs metastasise rapidly and cause systemic histamine effects including gastrointestinal ulceration and anaphylaxis. The key welfare intervention is early detection through monthly owner skin checks and prompt veterinary cytology or biopsy of any new or changing skin lump. Owners who delay assessment of skin masses — assuming they are benign — risk allowing treatable tumours to progress to stages where outcomes are far worse. Sun protection for high-risk dogs (lightly pigmented, short-haired breeds in sunny climates) is a practical primary prevention measure for SCC.