Abstract: Background and purpose: Most of differentiated thyroid cancer (DTC) has favorable prognosis, however, there are still a certain number of patients with recurrence after first operation. This study aimed to report the treatment outcome of 125 cases of persistent/recurrent DTC, and to predict risk factors for prognosis in DTC. Methods: A total of 125 cases of recurrent/persistent DTC patients who underwent surgery between 2008 and 2017 were retrospectively analyzed. The American Thyroid Association (ATA) dynamic risk stratification (DRS) was used to evaluate treatment outcome during follow-up. Results: A total of 125 DTC patients were enrolled in this study, including 26 male patients and 99 female patients, with mean age of 42 years. Forty-five (45/125, 36.0%) cases recurred in remnant thyroid, and nodal recurrence occurred in the central neck in 56 (56/125, 44.8%) patients, lateral neck in 58 (58/125, 46.4%) patients. The post-operation complications included 3 cases of permanent hypoparathyroidism and 4 cases of permanent recurrent laryngeal nerve palsy. The mean follow-up time was 61 months, and 5-year complete remission rate was 69.6% (87/125). Multivariate analysis showed that the number of previous operations was an independent variable predictor of prognosis in DTC patients (OR=2.948, 95% CI: 1.125-7.725, P=0.028). Conclusion: Remnant thyroid recurrence and lymph node metastasis are the main reasons for disease recurrence/persistence in DTC. We recommend experienced surgeons conduct reoperation because of high risk of complications. The number of previous operations is an independent variable predictor of prognosis in DTC patients.

Key words: Differentiated thyroid cancer (DTC), Persistent, Recurrent, Dynamic risk stratification