Thyroid tumors in dogs are uncommon but serious, with most being malignant carcinomas that can spread to the lungs and lymph nodes, requiring multimodal treatment for best outcomes.
Thyroid cancer in dogs creates welfare challenges through both the disease itself and its treatment. Large thyroid tumors may compress the trachea and esophagus, causing breathing difficulty, coughing, and difficulty swallowing — distressing symptoms that progressively worsen without treatment. Malignant tumors have high metastatic potential, meaning the disease spreads and causes systemic illness. Surgical removal of large or invasive tumors carries significant perioperative risk. Radioactive iodine therapy requires strict isolation during the treatment period, which is stressful for social animals. Despite these challenges, the meaningful survival times achievable with treatment mean that welfare-conscious intervention is often appropriate. Regular monitoring for recurrence and metastasis is essential for maintaining quality of life throughout the post-treatment period.