Radioiodine Literature

Below is a list of scientific articles that deal directly or indirectly with radioiodine therapy for thyroid carcinoma.

The articles are sorted by date with the most recent at the top. A link to the source of the article is available by clicking on the article title.


Clinical Features and Treatment Outcomes of 41 Dogs with Sublingual Ectopic Thyroid Neoplasia
Broome M.R., Peterson M.E. and Walker J.R.
J Vet Intern Med, 2014. 28(5): p.1560-8.
BACKGROUND: Thyroid neoplasia is common in dogs, but there are few reports of dogs with ectopic, sublingual thyroid tumors.
OBJECTIVES: To describe clinical features and outcomes of dogs with ectopic, sublingual thyroid neoplasia.
ANIMALS: Five hundred and forty-four dogs with thyroid neoplasia. METHODS: This retrospective study reviewed the medical records of dogs referred for thyroid neoplasia between 1995 and 2013. Data extracted included signalment, extent of thyroid disease (eutopic or ectopic; metastasis), serum thyroxine (T4 ) concentration, treatment, and survival.
RESULTS: Of 544 dogs with thyroid neoplasia, 41 (7.5%) dogs had ectopic sublingual thyroid tumors. The clinical features of these 41 dogs were similar to the cohort group of 503 dogs with eutopic or ectopic mediastinal thyroid tumors, but dogs with sublingual tumors were younger and less likely to have metastatic disease (15% versus 30%, P < .05). Of the 41 dogs, 28 received treatment: 21 with surgery (which included partial hyoidectomy in 13), 7 with radioiodine alone, and 13 with surgery followed by administration of radioiodine. Overall median survival was 562 days (range, 1-1,850 days).
CONCLUSIONS AND CLINICAL IMPORTANCE: When compared with eutopic thyroid carcinomas, ectopic sublingual thyroid tumors generally have a less aggressive biologic behavior. Many dogs have prolonged survival, even without treatment, although death because of local tumor invasiveness or metastasis can develop in some dogs. Surgical thyroidectomy, including partial hyoidectomy, is generally effective for control of local disease. Administration of radioiodine, alone or in combination with surgical treatment, is recommended for multifocal disease or metastasis.


Sodium iodide I-131 treatment of dogs with nonresectable thyroid tumors: 39 cases (1990-2003)
J Am Vet Med Assoc. August 2006;229(4):542-8.
Jane M Turrel, Margaret C McEntee, Blaise P Burke, Rodney L Page
OBJECTIVE: To determine outcome for dogs with nonresectable thyroid carcinomas treated with sodium iodide I-131 and identify factors associated with outcome.
DESIGN: Retrospective case series. Animals-39 dogs. PROCEDURES: A definitive or presumptive diagnosis of thyroid tumor was made on the basis of cytologic or histologic examination, abnormal accumulation of sodium pertechnetate Tc 99m during scintigraphy, or both, and dogs were treated with sodium iodide I-131. Dogs with cervical thyroid tumors were evaluated 3 to 6 weeks after 131I therapy, and residual tumor was resected when feasible. RESULTS: Prior to 131I therapy, 32 dogs had a solitary mass and 7 had metastases; 21 were hyperthyroid, 16 were euthyroid, and 2 were hypothyroid. Median survival time for dogs with local or regional tumors (ie, stage II or III) was significantly longer (839 days) than median survival time for dogs with metastasis (366 days). Tumor site (cervical vs ectopic), dose of sodium iodide I-131, age, body weight, treatment (131I therapy alone vs 131I therapy followed by surgery), and serum T4 concentration prior to 131I therapy were not significantly associated with survival time. Three dogs died of radioiodine-associated myelosuppression within 3 months after treatment, but no specific factor associated with development of toxicosis was identified.
CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that 131I therapy may result in prolonged survival times in dogs with nonresectable thyroid tumors, regardless of serum thyroxine concentration prior to treatment. Dogs undergoing131I therapy should be monitored for signs of bone marrow suppression.

Radioiodide (131I) therapy for the treatment of canine thyroid carcinoma
Aust Vet J. April 2005;83(4):208-14.
A J Worth, R M Zuber, M Hocking
OBJECTIVE: To assess the efficacy of radioactive iodine treatment (131I) for canine thyroid carcinoma, as both the sole therapeutic modality and as an adjunct to surgery. DESIGN: Retrospective analysis of case records from the Gladesville Veterinary Hospital Nuclear Medicine Service, Sydney, between August 1988 and December 2001.
CASE DETAILS: The records of 65 dogs with thyroid carcinoma were analysed according to therapy and outcome. Forty-three dogs received radioiodide therapy, either as the sole therapeutic modality (32) or as an adjunct to surgery (11). Radioisotope therapy consisted of one to three doses of 131I with a dose range of 555 to 1850 MBq. For analysis, dogs were divided into groups according to therapy: no treatment, surgery alone, surgery with radioiodide therapy or radioiodide therapy alone. Mode of therapy, dosage of 131I, clinical staging and age were all independently analysed according to survival to compare efficacy or predictive value respectively.
RESULTS: When radioiodide therapy was used as an adjunct to surgery, median survival was 34 months. Censored median survival time for dogs that received radioiodide alone was 30 months. Dogs that did not receive treatment had a median survival of only 3 months. Log rank statistical analysis indicated that mode of therapy was significantly correlated with survival but that clinical stage of disease was not.
CONCLUSION: The authors conclude that 131I therapy is effective at extending survival time, both as a sole therapeutic modality and as an adjunct to surgery, in dogs with invasive canine thyroid carcinoma. Incomplete surgical resection may not prolong survival in dogs also receiving 131I therapy, however surgical resection with curative intent should be recommended as the first line of therapy for mobile thyroid carcinomas. Radioisotope therapy can be recommended for cases where surgery alone is considered unlikely to be curative because of metastatic disease or local invasion, or for cases where surgery has been attempted but complete surgical removal has not been achieved.


Treatment Of Differentiated Thyroid Carcinoma In 7 Dogs Utilizing 131-I
Vet Radiol Ultrasound1995 ;36(5):417-424. 46 Refs
William H. Adams, Michael A. Walker, Gregory B. Daniel, Mark G. Petersen, Alfred M. Legendre
Seven dogs with thyroid gland carcinoma were treated with 131I and hormone suppressive therapy either alone (3 dogs) or in combination with surgery (3 dogs) or 137Cs teletherapy and chemotherapy (1 dog). Empirically chosen doses of 75 to 137 mCi of 131I were given orally (2 dogs) and intravenously (5 dogs). Adverse effects were limited to acute, transient bone marrow hypoplasia and pancytopenia. Nominal objective reduction in tumor volume or size and number of pulmonary metastases was observed in 4 dogs treated with 131I and thyroxine. Of these 4 dogs, 2 had stable disease for periods of 4 and 12 months while a third dog had stable disease for 27 months following two <sup>131</sup>I treatments at 3 month intervals. The fourth dog had progressive disease. Two dogs with mediastinal metastases showed reduction in localization of 99mTc-pertechnetate and radioiodine following 2 and 3 treatments using 131I. It appears that relatively high doses of 131I can be used safely for the treatment of canine thyroid tumors and that further investigation can be justified to define its efficacy.


Radioactive iodine treatment of a functional thyroid carcinoma producing hyperthyroidism in a dog
J Vet Intern Med. 1989 Jan-Mar;3(1):20-5.
M E Peterson, P P Kintzer, J R Hurley, D V Becker
Radioactive iodine (131I) was used in the treatment of a 12-year-old female dog with hyperthyroidism resulting from a large, unresectable (and metastatic) thyroid carcinoma associated with signs of severe inspiratory stridor and dyspnea. Hyperthyroidism was diagnosed on the basis of clinical signs (polyuria, polydipsia, polyphagia, weight loss, nervousness) and high basal serum thyroxine (T4) concentrations, as well as thyroid radioiodine kinetic studies that showed a high radioiodine uptake into the thyroid (% thyroid uptake) and markedly increased serum concentrations of protein-bound iodine-131 (PB131I) after 131I tracer injection. Thyroid imaging revealed diffuse radionuclide accumulation by the tumor, which involved both thyroid lobes. The dog was treated with three large doses of radioiodine (131I), ranging from 60 to 75 mCi, given at intervals of 5 to 7 months. The dog became euthyroid, and the size of the tumor decreased by approximately 25% after each 131I treatment, improving the severe inspiratory stridor and dyspnea, but both the hyperthyroid state and breathing difficulty recurred within a few months of each treatment. The dog was euthanatized 5 months after the last treatment because of progressive tracheal compression and pulmonary metastasis.