Thermal Ablation of Cervical Metastases From Thyroid Carcinoma

Inclusion Criteria: * 18 years of age or older * Patients with fine needle aspiration biopsy (FNAb)-proven metastatic cervical lymph nodes at levels I, II, III, IV, V, VI or VII from differentiated thyroid carcinoma or medullary thyroid carcinoma who underwent total thyroidectomy and subsequent radioiodine therapy, in case of differentiated thyroid carcinoma. * Patients considered high surgical risk candidate or patients who are informed about the ablation therapy and prefers it instead surgery; * Patients with metastatic cervical lymph nodes over 0.8 cm diameter and under 4.0 cm diameter; no more than 6 simultaneous cervical nodal metastases; * Cervical recurrences in previously lateral neck dissection patients for differentiated thyroid carcinoma or medullary thyroid carcinoma over 0.8 cm diameter. Exclusion Criteria: * Age under 18 years * Uncorrectable coagulopathy; * Inconclusive or benign cytologic specimens; * Pregnancy or breast-feeding; * Anaplastic or poor-differentiated thyroid carcinoma; * Partial thyroidectomy * Cervical tumors not considered to surgery (invading vessels, nerves, larynx or trachea); * Serious medical illness, including any of the following: uncontrolled angina, myocardial infarction, cerebrovascular event within 6 months prior to the baseline visit, uncontrolled congestive heart failure; * Participation in other studies that could affect the primary endpoint