Patients in high and moderate risk groups with no radiological evidence of lymph node metastases, intrathyroidal MTC smaller than 1 cm and calcitonin levels less than 20 or 30 ng/L are unlikely to have lymph node metastases and should be considered for total thyroidectomy alone (Machens et al. 2009, Rohmer et al. 2011). This evidence concerns the gene CALCA and metastatic malignant neoplasm in the lymph nodes.