A Temporal Analysis of Surgical Management and Outcomes Following ATA Guideline Updates in Papillary Thyroid Carcinoma: A Real-World Cohort Study of 31,861 Patients in South Korea

BACKGROUND: The American Thyroid Association (ATA) guideline revisions in 2009 and 2015 encouraged a shift toward less extensive surgery and reduced use of radioactive iodine (RAI) in the management of patients with low-risk papillary thyroid carcinoma (PTC). The aim of this study was to evaluate the real-world impact of these guideline changes on treatment patterns, complications, and oncologic outcomes. METHODS: In this retrospective cohort study conducted at a high-volume tertiary center in South Korea, we analyzed 31,861 patients treated for PTCs measuring ≤4 cm during 2004-2020. Patients were stratified into three temporal cohorts (triad 0 2004-2009; triad 1: 2010-2015; and triad 2: 2016-2020), and exact matching was performed to balance clinicopathologic characteristics across the groups. Segmented regression analysis was used to identify treatment pattern shifts. Postoperative complications and disease-free survival (DFS) were compared across the matched cohorts by using conditional logistic and stratified Cox regression analyses. Five-year restricted mean survival time (RMST) analysis was performed to adjust for follow-up variation. RESULTS: < 0.001) while transient complications remained stable. Although recurrence rates were lowest in the most recent era (1.3%), DFS analysis revealed higher hazard ratios for recurrence in triad 2 versus earlier cohorts (triad 2 vs. 0 hazard ratio: 1.520, confidence interval: 1.160-1.980). However, 5-year DFS and RMST comparisons revealed no significant differences. CONCLUSIONS: ATA guideline-driven de-escalation strategies were successfully implemented in real-world practice in this study, reducing overtreatment and surgical morbidity without compromising short-term oncologic outcomes.