Opsahl EM, et al. - In this study, researchers assessed the ability of serum calcitonin to predict the extent of surgery needed in the lateral neck. The study sample included 94 of 139 patients with medullary thyroid carcinoma (MTC) surgically treated in Norway from 2003 to 2016. Extrathyroidal extension and no biochemical cure were factors associated with metastatic lymph nodes in the lateral neck. Findings suggested that the need for prophylactic lateral lymph node dissection in MTC patients cannot be predicted by basal calcitonin.