Stage III includes: T1-3, N1a, M0. T1: Tumor measuring 2 cm or less in greatest dimension limited to the thyroid. T2: Tumor measuring more than 2 cm but less than 4 cm in greatest dimension limited to the thyroid. T3: Tumor measuring 4 cm or more in greatest dimension or with extrathyroidal extension. N1a: Metastasis to level VI or VII (pretracheal, paratracheal, or prelaryngeal/Delphian, or upper mediastinal) lymph nodes. This can be unilateral or bilateral disease. M0: No distant metastasis. (from AJCC 8th Ed.) [from NCI]