Stage I and II Papillary and Follicular Thyroid Cancer
Of the 1,298 patients, 911 patients received RAI after surgery, and 387 patients did not receive RAI after surgery. Follow-up period was 10.3 years; in multivariate analyses, there were no differences in OS (P = .243) or DFS (P = .2659), according to RAI use.
Long-term complications of RAI using I131 include second malignancies, sialadenitis, and lacrimal and salivary gland dysfunction. Options for reducing the amount of radiation exposure by reducing the amount of RAI in each dose and also to give RAI in combination with rhTSH injections have been explored for low-risk thyroid cancer patients.
Two phase III, randomized, noninferiority studies of patients with low-risk thyroid cancer using a comparison of two thyrotropin-stimulation methods (thyroid hormone withdrawal or use of rhTSH) and two doses of radioiodine I131 1.1GBq [30mCi] and 3.7GBq [100mCi] using a 2 × 2 factorial design showed equivalent thyroid ablation rates between high and low dose I131 at 6 to 10 months after administration of I131.[15,16][Levels of evidence: 3iA and3iDii] However, differences in the inclusion criteria in one study  consisted of a low-risk, homogeneous cohort in which all of the patients underwent total thyroidectomy, and had pathological TNM stage pT1 ( ≤1 cm) and N1 or Nx, pT1 (>1–2cm) and any N stage, or pT2N0 without thyroid capsule extension/distant metastases. Complete thyroid ablation rate in this study was 92%. Patients undergoing thyroid hormone withdrawal had greater symptoms of hypothyroidism associated with deterioration in quality of life compared with the rhTSH group.
In the other study, patients with more advanced T stage (T1–T3, N0–1) and with less than a total thyroidectomy were included with a lower overall ablation rate of 85%. Neither study assessed the effect of low-dose RAI on long-term recurrences or survival. The studies also did not address whether RAI could be safely omitted in specific low-risk groups.
Current Clinical Trials
Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage I papillary thyroid cancer, stage I follicular thyroid cancer, stage II papillary thyroid cancer and stage II follicular thyroid cancer. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.
General information about clinical trials is also available from the NCI Web site.
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