A Prospective Study of Publicly Funded Molecular Testing of Indeterminate Thyroid Nodules: Canada's Experience

Context: Indeterminate thyroid nodules (ITNs) lead to diagnostic surgeries in many countries. Use of molecular testing (MT) is endorsed by several guidelines, but costs are limitative, especially in public healthcare systems like in Canada.

Objectives: Primary objective: evaluate the clinical value of Thyroseq® v3 (TSv3) using benign call rate (BCR) in a real-world practice. Secondary objective: assess cost-effectiveness of MT.

Design: This is a multicentric prospective study.

Setting: This study was conducted in 5 academic centers in Quebec, Canada.

Patients or other participants: 500 consecutive patients with Bethesda III (on 2 consecutive cytopathologies) or IV and TIRADS 3 or 4 nodules measuring 1 to 4 cm were included.

Intervention: MT was performed between November 2021 and November 2022. Patients with a positive TSv3 were referred to surgery. Patients with a negative TSv3 were planned for follow-up by ultrasonography for a minimum of 2 years.

Main outcome measure: The BCR, corresponding to the proportion of ITNs with negative TSv3 results, was assessed.

Results: 500 patients underwent TSv3 testing, with a BCR of 72.6% (95% CI: 68.5-76.5; p<0.001). 99.7% of patients with a negative result avoided surgery. The positive predictive value of TSv3 was 68.2% (95% CI: 58.5-76.9). The cost-benefit analysis identified that the implementation of MT would yield cost savings of $6.1 million over the next 10 years.

Conclusions: Use of MT (TSv3) in a well-selected population with ITNs led to a BCR of 72.6%. It is cost-effective and prevents unnecessary surgeries in a public healthcare setting.