no regional lymph nodes or distant metastases no residual bulk tumor
no external invasion of the tumor
non-malignant histological subtype of high degree
no iodine uptake outside the thyroid bed on first postoperative whole-body nuclear scan no vascular invasion
cN0 or less than 5 small lymph node metastases (<0.2 cm in diameter)
Follicular subtype PTC, located within the thyroid, not breaching the envelope; tiny thyroid papillae
FTC, located in the thyroid, well differentiated, with envelope invasion and no vascular invasion, or with only microvascular invasion
Microinvasion of peri-thyroidal tissue
First postoperative nuclear imaging with iodine uptake in the neck lesion
subtype with high malignancy (hypercellular, columnar cell, diffuse sclerosis, etc.) with vascular invasion
cN1 or pN1 with more than 5 lymph node metastases and metastases less than 3 cm in diameter
Multifocal papillary microcarcinoma of the thyroid with or without BRAF V600E mutation
Obvious invasion of soft tissue tumor residue around the thyroid
distant metastasis
High postoperative serum Tg suggesting distant metastases
pN1 and metastatic lymph node metastases ≥3cm in diameter
Extensive vascular invasion of follicular thyroid cancer (>4 vascular invasions)