However, other risk factors for recurrence, such as 131I-avid metastatic foci in the neck on the first post-treatment whole-body radionuclide scan (intermediate risk), incomplete tumor resection (high risk) and detection of elevated postoperative serum thyroglobulin suggestive of distant metastases (high risk), were not analyzed in our study due to the lack of available data in the SEER database (10). This evidence concerns the gene TG and neoplasm.