Active Surveillance of Papillary Thyroid Microcarcinoma

Inclusion Criteria: 1. \< 1 cm solitary nodule 2. Surrounded by ≥ 2 mm normal thyroid parenchyma 3. Subcapsular locations not adjacent to surrounding structures, recurrent laryngeal nerve, trachea, or carotid artery 4. No evidence of invasion to surrounding structures, recurrent laryngeal nerve, trachea or carotid artery 5. No extrathyroidal extension 6. Clinically N0 and Clinically M0 7. ≥ 18 years 8. Combined severe comorbidities or Inoperable condition (optional) 9. No wish to surgery and Willingness to accept active surveillance 10. No history of radiotherapy on head and neck area 11. Accepted by the Board of Thyroid Cancer Meeting Exclusion Criteria: 1. ≥ 1 cm nodule and multifocal nodules regardless of size 2. Papillary thyroid carcinoma variants associated with poor prognosis (tall cell variant, columnar variant, hobnail variant) or other types of thyroid cancer) 3. Subcapsular locations adjacent to surrounding structures, recurrent laryngeal nerve, trachea or carotid artery 4. Evidence of invasion to surrounding structures, recurrent laryngeal nerve, trachea or carotid artery 5. Extrathyroidal extension 6. Any of N1 or M1 7. Documented increase in size according to America Thyroid Association (ATA) guideline in a previously confirmed Papillary thyroid microcarcinoma 8. \< 18 years 9. Not willing to accept observational active surveillance approach