Treatment of thyroid carcinoma in dogs by surgical resection alone: 20 cases (1981-1989).

Of 82 dogs with thyroid carcinoma seen between January 1981 and October 1989, 20 had freely movable tumors without evidence of metastasis and were treated with surgical excision alone. Uncensored mean and median survival times for these 20 dogs were both 20.5 months. Kaplan-Meier survival analysis, which censors for nontumor-related deaths and dogs lost to follow-up, indicated that median survival time was greater than 36 months. Seven dogs died of tumor-related causes: 2 died because of metastasis or local recurrence of the tumor, 5 died of treatment-related complications (eg, laryngeal paralysis, hypocalcemia, tracheostomy complications). Eight dogs died of unrelated causes; 1 dog was lost to follow-up at 26 months after surgery; 3 dogs were alive 19, 24, and 26 months after surgery. Cause of death could not be determined in the remaining dog. Long-term survival is possible following surgical removal of mobile thyroid carcinomas in dogs.