Table 1. Details of the Canadian study inclusion and exclusion criteria for active surveillance (at baseline assessment, prior to deciding on surgery or active surveillance)*.

Inclusion criteria	Exclusion criteria
Age ≥18 years	Known regional or distant metastatic thyroid cancer at the time of baseline evaluation (prior to thyroid cancer surgery)
Newly diagnosed, previously untreated papillary thyroid cancer (PTC) <2 cm in maximal diameter on ultrasound imaging	A history of prior thyroid cancer surgery
Fine needle aspiration biopsy of the primary tumour must be read as either PTC or suspicious for PTC (as reviewed by a cytopathologist at a participating study site)	The primary PTC is adjacent to the recurrent laryngeal nerve or trachea
No evidence of metastatic cervical lymphadenopathy on ultrasound imaging of the neck (or other neck imaging)	Known or suspected poorly differentiated or non-papillary thyroid cancer
No other potential indication for thyroid or parathyroid surgery at the time of the assessment	Medically unfit for surgery due to comorbidity
Patient permission must be granted for review of thyroid cancer-related medical records to determine study eligibility	Another active malignancy (excluding non-melanoma skin cancer) for which patients are receiving treatment or are less than 3 years from completing treatment
	Pregnancy at the time of study enrolment
	Other current indications for thyroid or parathyroid surgery
	Patient is unable to provide informed consent for the study or comply with study follow-up procedures due to current severe active cognitive or psychiatric impairment, substance abuse or other reasons

*Eligible consenting patients participating in the respective follow-up arms of the study (i.e., active surveillance or surgery) must have been enrolled in the first phase of the study, where standardised information about papillary thyroid cancer prognosis and active surveillance is offered. Consenting eligible patients in the surgical follow-up arm are enrolled after first thyroid cancer surgery is completed. Reproduced with authorization (open-access journal) from Sawka AM, et al. BMJ Open 2018;8:e020298.