Persistent and Recurrent Differentiated Thyroid Cancer: A Surgical Perspective on Overdiagnosis.

[OBJECTIVE] Differentiated thyroid carcinoma (DTC) shows excellent long-term survival, yet its global incidence has markedly increased due to widespread imaging and fine-needle aspiration biopsy, raising concerns about overdiagnosis and overtreatment. The upcoming 2025 American Thyroid Association (ATA) guidelines redefine disease-free status (DFS), persistent disease, and recurrence based on a 90-day cutoff, representing a major conceptual shift from the 2015 ATA framework. This study aimed to evaluate early reoperations in a single-center DTC cohort in light of the ATA 2015 and 2025 classifications to determine whether early reoperations represent persistence or true recurrence.

[METHODS] A retrospective analysis of 81 patients (52 females, 29 males; median age: 44 y) who underwent DTC surgery between 2016 and 2023 was conducted. Demographic, pathologic, and biochemical data, including serum thyroglobulin (Tg) levels, were analyzed. The time interval between primary and reoperative surgery was classified using both 3- and 12-month cutoffs.

[RESULTS] Reoperation occurred in 63% of patients within 12 months and in 27% within 3 months. Most early reoperations (≤12 mo) represented persistence by the ATA 2015 criteria but were reclassified as recurrence under the ATA 2025 definitions. Thyroglobulin (Tg) levels did not correlate with reoperation timing. Neck dissection was associated with higher complication rates (P=0.002) and greater rates of vascular and extrathyroidal invasion.

[CONCLUSION] Most early reoperations in DTC represent true recurrence under the ATA 2025 framework. Standardized DFS-based classification, dynamic risk stratification, and compartment-oriented surgery performed by experienced teams can optimize outcomes and reduce unnecessary reoperations.