Impact of the 2015 American Thyroid Association Guidelines on Treatment of Low-Risk Thyroid Cancer.

Objectives: The 2015 American Thyroid Association (ATA) guidelines recommended lobectomy for management of low-risk differentiated thyroid carcinomas (DTC), aiming to mitigate overtreatment. The primary objective of this study was to assess the impact of the 2015 ATA guidelines on the rates of lobectomy versus total thyroidectomy for the treatment of low-risk DTC, using the Surveillance, Epidemiology, and End Results (SEER) 17 database. Our secondary objectives were to examine the modifying effects of tumor size on the change in the rates of lobectomy between the pre- and post-guideline periods and to identify factors that are associated with the use of lobectomy in the post-guideline period. Methods: A retrospective cohort analysis of adults diagnosed with low-risk DTC from 2011 to 2020 was conducted using the SEER 17 database. Logistic regression assessed the likelihood of lobectomy and total thyroidectomy before and after guideline implementation, including size-stratified and post-guideline subgroup analyses. Results: Among 61,078 patients, lobectomy rates increased from 16% pre-guideline to 25% post-guideline (aOR 1.81, 95% CI 1.74-1.89). Lobectomy increased across both T1 and T2 tumors; post-guideline subgroup analysis indicates T2 tumors were less likely to receive lobectomy than T1 tumors. Conclusions: The use of lobectomy for treatment of low-risk DTC has significantly increased since the publication of the 2015 ATA guidelines. However, total thyroidectomy remains the predominant treatment. Level of Evidence: Level 3.