Optimal Thyrotropin Suppression Therapy in Low-Risk Thyroid Cancer Patients after Lobectomy

Background: This study aimed to identify the clinical results after thyrotropin suppression therapy (TST) cessation and evaluated clinical factors associated with successful TST cessation. Methods: Patients who underwent lobectomy due to low-risk papillary thyroid carcinoma (PTC) were included in this study. We compared clinical characteristics and outcomes between patients who succeeded to stop TST and failed to stop TST. Results: A total of 363 patients were included in the study. One hundred and ninety-three patients (53.2%, 193/363) succeeded to stop TST. The independent associated factors for successful TST cessation were the preoperative thyroid-stimulating hormone (TSH) level and the maintenance period of TST. Patients with low TSH level showed a higher success rate for levothyroxine (LT4) cessation than patients with high TSH level (1.79 +/- 1.08 and 2.76 +/- 1.82 mU/L, p < 0.001). Patients who failed to discontinue TST showed a longer maintenance period of TST than patients who succeeded to discontinue TST (54.09 +/- 17.44 and 37.58 +/- 17.68 months, p < 0.001). Conclusions: Preoperative TSH level and maintenance period of TST are important factors for successful cessation of TST. If TST cessation is planned for patients who are taking LT4 after lobectomy, a higher success rate of TST cessation is expected with low preoperative TSH level and early cessation of LT4.