Those who had high risk features on pathologic examination were as follows: 82 patients had macroscopic gross extrathyroidal extension, 24 patients had pathologic N1 with any metastatic lymph node >3 cm in largest dimension, 15 patients had postoperative serum thyroglobulin suggestive of distant metastases, or 1 patient had follicular thyroid cancer with extensive vascular invasion (>4 foci of vascular invasion). This evidence concerns the gene TG and thyroid gland follicular carcinoma.