Addition of Lithium to Radioactive Iodine Treatment With Improved Response in a Woman With Progressive Papillary Thyroid Carcinoma

ABSTRACT Objective: Differentiated thyroid carcinoma (DTC) treatment includes surgery and therapy with radioactive iodine (RAI) (131I) of thyroid remnants and metastases. The objective of this report is to describe an improved response in a woman with progressive papillary thyroid carcinoma, and adjuvant lithium carbonate therapy in order to enhance 131I efficacy. Methods: A young woman underwent total thyroidectomy with bilateral cervical lymph node dissection for a multicentric papillary carcinoma. Despite 8 therapeutic doses of 131I, the patient showed a negative 131I scan and increasing thyroglobulin values. After preparation with oral administration of 600 mg of lithium and a 15-day regimen of 300 mg (3 times/day), which was adjusted according to the patient's daily recorded serum lithium level, a dose of 150 mCi of 131I was administered on day 15. Results: After this procedure, the patient showed for 5 continuous years the lowest thyroglobulin levels observed during her follow-up, and she remains clinically and radiologically stable. Conclusion: In progressive, high-risk DTC with 131I-resistant metastatic disease, the combination of radioiodine with lithium in an adequately controlled protocol might be of benefit. Prospective studies comparing RAI therapy alone to RAI therapy plus lithium in similar groups of patients with DTC are needed to demonstrate that lithium with RAI therapy is superior to RAI therapy alone. Abbreviations: DTC = differentiated thyroid carcinoma RAI = radioactive iodine Tg = thyroglobulin TSH = thyroid-stimulating hormone