TG and metastatic malignant neoplasm in the lymph nodes: As Figure 1 shows, it could be suggested that the lymph node metastasis status, thyroid capsular invasion, and preoperative Tg levels in combination with a certain cut-off level of ablative Tg can assist clinical decision-making about whether to perform follow-up sTg measurements after remnant RAI ablation in patients at intermediate and high risk of recurrence.