There is a lack of strong evidence for the optimal frequency of follow-up for thyroid nodules. In most benign thyroid nodules, follow-up can be done at 6-12 month intervals. For suspected malignant or malignant nodules that are not yet treated, the follow-up interval can be shortened. History taking and physical examination and review of neck ultrasound must be performed at each follow-up visit. Some patients (those with abnormal thyroid function found during the initial evaluation, those treated with surgery, TSH suppression therapy or 131I) also need to be followed up for thyroid function. If nodules are found to be significantly growing during follow-up, special attention should be paid to the presence of symptoms, signs (such as hoarseness, difficulty breathing/swallowing, nodule fixation, enlarged lymph nodes in the neck, etc.) and ultrasound signs that suggest nodule malignancy. “Significant growth” is defined as an increase in nodule volume of more than 50% or at least 2 diameter lines of more than 20% (and more than 2 mm), which is an indication for FNAB; for cystic nodules, the decision to perform FNAB is based on the growth of the solid portion.