Effect of Lithium Carbonate on Low-Dose Radioiodine Therapy in Early Thyroid Cancer
Effect of Lithium Carbonate on Low-Dose Radioiodine Therapy in Early Thyroid Cancer
This study will examine the safety and effectiveness of using lithium, which has been used to
 enhance the effectiveness of high-dose 131I, with a single low dose (30 mCi) of 131I for
 thyroid ablation in patients with recently diagnosed papillary or follicular thyroid cancer
 who have had their thyroid gland removed and whose cancer has not spread beyond the thyroid.

 Participants are randomly assigned to receive lithium capsules or placebo (look-alike
 capsules with no active ingredient). They follow a low-iodine diet for 2 weeks before
 starting treatment and are then admitted to the NIH Clinical Center for study and treatment
 for 11 days, during which they remain on the low-iodine diet. Blood samples are collected
 almost every day to analyze thyroid hormones, kidney and liver function, lithium
 concentrations and other tests.
Postsurgical thyroid remnant ablation with (131)I is considered standard clinical care for
 most cases of papillary and follicular thyroid cancer, to eliminate normal thyroid tissue
 which may contain microscopic cancer. Furthermore, ablation enhances the sensitivity of
 subsequent (131)I scanning and serum thyroglobulin (TG) measurement for the detection of
 recurrent or persistent disease. Low dose (131)I (30 mCi) successfully ablates thyroid
 remnant in 8-61% of cases. This dose can be repeated and result in overall less radiation
 exposure than that associated with high dose therapy (100 mCi). Ablation achieved with one or
 more small doses of radioactive iodine is not associated with decreased survival or cancer
 recurrence. According to the literature there is no difference in the 30-year recurrence
 rates between groups receiving low and high dose ablation therapy for well differentiated
 thyroid cancer without distant metastases at the time of initial therapy. The benefits of
 using low dose of (131)I are minimization of whole body radiation exposure, reduction in side
 effects and lower cost. Higher rates of successful ablation by low dose of 131I could be
 achieved by increasing uptake of (131)I and/or lengthening retention of radioiodine in the
 remnant thyroid tissue. Recombinant human thyroid-stimulating hormone (rhTSH) has been used
 successfully to increase radioiodine uptake. Lithium has been used to increase radioiodine
 retention and has been shown to be useful in the treatment of residual or metastatic cancer.
 The combination of rhTSH and lithium as adjuncts to 30 mCi radioactive iodine (RAI) ablation
 therapy in low risk thyroid cancer patients may provide a method that reduces the cumulative
 dose of radioiodine needed to successfully treat thyroid cancer. The specific aim of this
 study is to determine whether adjunct lithium carbonate improves the success rate of
 postsurgical ablation of thyroid remnants using low dose (131)I (30 mCi) and rhTSH in low
 risk patients with differentiated thyroid carcinoma. Patients with well-differentiated
 papillary or follicular thyroid cancer stage I or II, according to the National Thyroid
 Cancer Treatment Cooperative Study (NTCTCS) classification at time of surgery, will be
 enrolled. Eligible patients will have had a total or near-total thyroidectomy within 6 months
 of enrollment. This randomized, placebocontrolled, double-blind study will permit an
 evaluation of the risk/benefit ratio of adding lithium as an adjuvant to the already
 established method of administering low-dose (131)I ablation therapy, to optimize the (131)I
 retention. All patients will undergo diagnostic rhTSH (123)I whole body scan at the end of
 the study to assess the success of thyroid ablation.
-  INCLUSION CRITERIA

 1. Patients older than 16 years with well-differentiated papillary or follicular
 thyroid cancer stage I or II, according to the NTCTCS classification at time of
 surgery

 2. Patients younger than 45 years with any size of primary papillary or follicular
 tumor

 3. Patients older than 45 years with:

 1. primary papillary tumor less than 4 cm or

 2. primary follicular tumor less than 1 cm

 -  EXCLUSION CRITERIA

 1. Patients with postsurgical thyroid remnant more than 5 g

 2. Patients with distant metastases

 3. Patients above 45 years of age having:

 1. known cervical lymph nodes metastases

 2. microscopic multifocal follicular cancer

 3. microscopic extraglandular invasion of follicular cancer

 4. gross extraglandular invasion of papillary or follicular cancer

 4. Patients with confirmed histological subtypes of well-differentiated thyroid
 cancer such as Hurtle cell carcinoma, insular and tall cell variants of papillary
 cancer.

 5. Pregnant or lactating women

 6. Patients with renal impairment defined as repeat serum creatinine concentrations
 above 1.5 mg/dl on thyroid hormone

 7. Patients on chronic lithium therapy for psychiatric illness

 8. Patients with current unstable cardiovascular conditions

 9. Patients with severe chronic medical conditions (liver failure, severe
 debilitation, dehydration, sodium depletion, any other cancer requiring therapy,
 etc)