Table 1 Key concepts at from a Canadian national investigator meeting regarding research on AS for low risk PTC

1. Currently in Canada, patients with small, low risk PTC, are typically referred for consultation on thyroid surgery (total or hemithyroidectomy) and this is established standard of care in our country.

2. Active surveillance (AS) of low risk papillary microcarcinoma (PTC ≤1 cm in maximal diameter) appears safe, based on the published literature (most of which is from Japan). More prospective long-term outcome research is needed regarding AS of larger low risk PTCs (i.e. primary tumors > 1 cm but < 2 cm).

3. Preliminary experience from Toronto, suggests that some Canadians with small, low risk PTC prefer the option of AS, over thyroid surgery, if given the choice. Patient participants at the meeting strongly valued patients being fully informed about both options, and the opportunity for patient involvement in medical decision-making.

4. Prospective AS research in low risk PTC should include patient-centered outcomes such as: disease progression requiring surgery (for patients under AS), disease persistence or recurrence requiring treatment (for the surgical arm), and validated measures of health-related quality of life and relevant related symptoms (such as anxiety).

5. Standardization of neck ultrasound interpretation and reporting, particularly with respect to eligibility criteria and criteria for disease progression, is of critical importance in conducting AS research for PTC.

6. A multi-center prospective observational cohort study comparing AS and surgery for small, low risk PTC is feasible to perform in Canada given the frequency of diagnosis, the availability of necessary technology and expertise, and a strong interest among clinicians to mitigating treatment-related harm in patients who may not benefit from surgery.

7. It will be important to compare the healthcare resource implications over time, of AS compared to surgery for low risk PTC, using Canadian healthcare costs.