Available online 7 October 2022, 100540

10-20% of differentiated thyroid cancers in Ontario are incidentally detected (IDCs)

IDCs involve pre-diagnostic use of non-thyroid imaging in the pathway to diagnosis

Per capita regional diagnostic imaging capacities are strongly and positively associated with IDCs

Unexpectedly, patient drivetimes from residence to imaging facility are positively associated with IDCs outside of rural areas

Access to primary care may play a role in local areas with higher odds of IDCs

Global increases in thyroid cancer incidence (≥90% differentiated thyroid cancers; DTC) are hypothesized to be related to increased use of pre-diagnostic imaging. These procedures can detect DTC during imaging for conditions unrelated to the thyroid (incidental detection). The objectives were to evaluate incidental detection of DTC associated with standardized, regional imaging capacity and drivetime from patient residence to imaging facility (the exposures). We conducted a population-based retrospective cohort study of 32,097 DTC patients in Ontario, 2003-2017. We employed sex-specific spatial Bayesian hierarchical models to evaluate the exposures and examine the adjusted odds of incidental detection by administrative regions. Regional capacities of computed tomography and magnetic resonance imaging scanners are positively associated with incidental detection, but vary by sex. Contrary to hypothesis, drivetimes in urban areas are positively associated with incidental detection. Access to primary care may play a role in several administrative regions with higher adjusted odds of incidental detection.

thyroid neoplasms

incidental findings

diagnostic imaging

drivetime analysis

Bayesian hierarchical modeling

The data that has been used is confidential.

The data that has been used is confidential.

© 2022 Published by Elsevier Ltd.