Surgical resection of recurrent differentiated thyroid cancer: patterns, detection, staging, and treatment of 683 patients

Background: Despite improvements in overall survival, the recurrence of differentiated thyroid cancer (DTC) is becoming more common and remains a challenge necessitating accurate reappraisal of the patient. This study aimed to describe the characteristics, reasons, morbidity, and strategies of second operations for DTC. Methods: This was a retrospective observational study of patients with DTC who underwent a second surgery between June 2008 and June 2021 in the Department of Thyroid Surgery at China-Japanese Union Hospital, Jilin University, P.R. China. All clinical characteristics were recorded, and the analysis was estimated using SPSS. Results: Second surgeries were detected in 683 patients. The proportion of second operations changed with the update of international guidelines from 2015 (P < 0.001). The true recurrence rate progressively increased from 21.3% to 61.5%. The rate of an "absence of preoperative FNA" or an "absence of intraoperative pathology at first surgery" decreased from 49.8% to 12.7%, while that of a "misdiagnosis of preoperative FNA at second surgery" decreased from 10% to 1.8%. The most common tumor location during the second surgery was the lateral lymph nodes (n = 104, 36.5%), with a median time to relapse of 36 months. Completion of thyroidectomy and lymph node dissection correlated with the second operation. Conclusion: After 2015, second surgeries were more standardized, the incidence of complications decreased, and real recurrence became the most common reason for a second DTC surgery.