What is ATA risk stratification?

Low risk (no metastasis, all tumor resected (R0/R1), no tumor invasion, no aggressive histology - these don't get radioactive iodine) Intermediate (microscopic invasion of surrounding soft tissues, cervical lymph node metastasis (N1a/b), aggressive histology - these are addressed individually) High risk (extrathyroid invasion, incomplete resection, distant metastasis - these receive radioactive iodine)