Does Postoperative Thyrotropin Suppression Therapy Truly Decrease Recurrence in Papillary Thyroid Carcinoma? A Randomized Controlled Trial

Context: TSH suppression therapy has been used to decrease thyroid cancer recurrence. However, validation of effects through studies providing a high level of evidence has been lacking. Objective: This single-center, open-label, randomized controlled trial tested the hypothesis that disease-free survival (DFS) for papillary thyroid carcinoma (PTC) in patients without TSH suppression is not inferior to that in patients with TSH suppression. Design: Participants were randomly assigned to receive postoperative TSH suppression therapy (group A) or not (group B). Before assignment, patients were stratified into groups with low- and high-risk PTC according to the AMES (age, metastasis, extension, size) risk-group classification. Interventions and Outcome Measures: For patients assigned to group A, l-T4 was administered to keep serum TSH levels below 0.01 μU/ml. TSH levels were adjusted to within normal ranges for patients assigned to group B. Recurrence was evaluated by neck ultrasonography and chest computed tomography. Results: Eligible participants were recruited from 1996–2005, with 218 patients assigned to group A and 215 patients to group B. Analysis was performed on an intention-to-treat basis. DFS did not differ significantly between groups. The 95% confidence interval of the hazard ratio for recurrence was 0.85–1.27 according to Cox proportional hazard modeling, within the margin of 2.12 required to declare 10% noninferiority. Conclusions: DFS for patients without TSH suppression was not inferior by more than 10% to DFS for patients with TSH suppression. Thyroid-conserving surgery without TSH suppression should be considered for patients with low-risk PTC to avoid potential adverse effects of TSH suppression. A randomized controlled trial shows that disease-free survival for patients without TSH suppression is not inferior by >10% to that for patients with TSH suppression.