Table 2. Characteristics of ongoing AS trials*.

Country	Hospital/Institution	Study title	Estimated duration	Estimated enrollment (participants)	Inclusion, maximal diameter	Status
Canada	University Health Network Toronto, Ontario	Deciding on AS or Surgery for Primary Management of Low Risk PTC	2016–2026	200	≤2 cm	Recruiting
United States	Cedars-Sinai Medical Center Los Angeles, California	AS of PTMC	2016–2030	216	≤2 cm	Recruiting
Italy	National Cancer Institute, Naples	AS versus Surgery in PTMC	2019–2023	40	≤1.3 cm	Recruiting
Korea	Seoul St Mary’s Hospital Seoul, Seocho-Gu	AS of PTMC	2016–2021	300	≤1 cm	Recruiting
Korea	Seoul National University Hospital	AS on PTMC	2016–2030	1,211	≤1 cm	Active, not recruiting

AS, active surveillance; PTC, papillary thyroid carcinoma; PTMC, papillary thyroid microcarcinoma. *data extracted from Clinicaltrials.gov on April 2020 (https://clinicaltrials.gov/ct2/results?cond=Active+Surveillance+Thyroid++&term=&cntry=&state=&city=&dist=)