Evaluation of the use of chemotherapy and other prognostic variables for surgically excised canine thyroid carcinoma with and without metastasis

This retrospective study compared the efficacy of surgery alone versus surgery in combination with chemotherapy in the treatment of canine thyroid carcinoma; potential prognostic factors were evaluated. Forty-four dogs with biopsy-confirmed thyroid carcinoma met the inclusion criteria. Twenty-eight dogs were treated with surgery alone and 16 with surgery and chemotherapy. The median survival of dogs treated with surgery and chemotherapy was 518 d, which was not statistically different from that of the dogs treated with surgery alone. The number of thyroid lobes removed at surgery was prognostic with respect to survival. Despite an overall metastatic rate of 48%, the addition of chemotherapy to surgical excision did not improve survival; however, this finding may be due to inadequate power to demonstrate a difference.