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131 ‐I therapy for Advanced, Unresectable Thyroid Tumors in Dogs
Author(s) -
Turrel J.,
Burke B.,
Ullman S.,
McEntee M.,
Page R.
Publication year - 2005
Publication title -
veterinary and comparative oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.864
H-Index - 34
eISSN - 1476-5829
pISSN - 1476-5810
DOI - 10.1111/j.1476-5810.2005.064ae.x
Subject(s) - medicine , thyroid , thyroid cancer , stage (stratigraphy) , radiation therapy , surgery , paleontology , biology
Greater than 50% of dogs with thyroid tumors present with surgically unresectable disease for which external beam radiotherapy has been reported to prolong survival. The success of 131 I for control of thyroid tumors in cats and in humans suggests such therapy may also play a role in the management of canine thyroid cancer. Methods: Thirty‐nine dogs with WHO stage II/III (invasive or ectopic; n = 32) or IV (metastatic; n = 7) thyroid tumors were treated with 131 I alone. Changes in thyroid function, 99M Tc‐pertechnetate ( 99M Tc) scintigraphic changes, and tumor response were recorded. Dogs with ventral cervical tumors were evaluated for feasibility of surgical resection following 131 I. Results: Median overall survival was 839 days and 366 days for dogs with stage II/III and stage IV tumors, respectively. Thyroid hormone status, site and surgical resection were not associated with outcome in dogs with stage II/III tumors. Three dogs developed severe bone marrow suppression. Conclusions: These findings suggest 131 I should be investigated more thoroughly in dogs with thyroid tumors not considered surgical candidates to more clearly characterize the indications for therapy and followup recommendations. 131 I dosimetry in dogs with thyroid tumors remains problematic. Administration of 131 I is currently based on empiric recommendations and, in general, the treatment is well tolerated although additional studies are indicated to optimize response and minimize toxicity.