Determinants of physicians' risk-benefit perceptions of adjuvant radioactive iodine for differentiated thyroid cancer

Selective use of radioactive iodine is advocated in recent guidelines. We aimed to characterize clinical practice and factors associated with its prescription in low- or intermediate-risk differentiated thyroid cancer patients among Spanish physicians.

A cross-sectional survey was conducted in 2022 among Spanish physicians. The survey assessed preferences for radioactive iodine administration in different differentiated thyroid cancer clinical scenarios with excellent response to surgery.

Ninety-six responses were received. In low-risk differentiated thyroid cancer, radioactive iodine was most often used to facilitate follow-up (40%), or to reduce the risk of recurrence (23%). Activity of radioactive iodine was selected according to treatment intention by 96% of respondents; but more than 50% of low-risk differentiated thyroid cancer patients received radioactive iodine treatment in the clinical setting of 2/3 of the respondents; and 13% routinely recommend adjuvant activities in this setting. In intermediate-risk differentiated thyroid cancer, the main objective of radioactive iodine administration was to reduce the risk of recurrence (81-83%). Adjuvant radioactive iodine was perceived to be well or very well tolerated (96% of respondents); with a positive risk-benefit balance in patients with low-risk (50%) or intermediate-risk (90%) differentiated thyroid cancer. Factors influencing physicians' likelihood to recommend radioactive iodine included an overestimation of its benefits; and underestimation of its risks; and perceived increased risk with increasing tumor size, nodal involvement, BRAF V600E mutation, and follicular/oncocytic histology.

This survey shows discrepancy between reported clinical practice and current consensus guidelines as well as variation in practice patterns in Spain regarding [¹³¹I]NaI treatment.