Is it worth suppressing TSH in low- and intermediate-risk papillary thyroid cancer patients before the first disease assessment?

Objective Guidelines recommend TSH suppression before the first response to treatment assessment in papillary thyroid cancer (PTC) patients. The aim of this study was to assess the rate of structural disease (SD) in low- and intermediate-risk PTC patients according to TSH levels measured 1 year after primary treatment. Methods A consecutive, prospective series of low- and intermediate-risk PTC patients with 3-years follow-up was collected. TSH, thyroglobulin, anti-thyroglobulin antibodies, and neck ultrasonography 1 and 3 years after primary treatment were analyzed. Recurrence risk and disease status at 1 year were defined according to the American Thyroid Association guidelines and as the presence or absence of SD after 3 years. Patients were grouped according to TSH level at 1-year: group-1 TSH <0.1uUI/mL; group-2 TSH 0.1-05uUI/mL; group-3 0.5-2uUI/mL; group-4 >2uUI/mL. Results This study included 263 patients (70.9% female, median age 47.2 years) of whom the risk of recurrence was low in 170(65%), intermediate-low in 63(24%), and intermediate-high in 30(11%). The response to initial treatment at 1 year was excellent in 149 patients (57%), biochemical incomplete in 18(7%), indeterminate in 84(32%), and structural incomplete in 12(4%). Group-1 consisted of 53 patients (20%), group-2 of 85 (32%), group-3 of 61 (23%) and group-4 of 64 (24%). The rate of SD at 1 and 3 years from primary treatment was not significantly different between TSH groups. Conclusion TSH suppression before the first response to treatment assessment does not appear to influence the rate of SD evaluated 1 and 3 years after primary treatment. Abbreviations: ATA = American thyroid association; DTC = Differentiated thyroid cancer; FTC = Follicular thyroid cancer; Neck US = Neck ultrasonography; PTC = Papillary thyroid cancer; Tg = Thyroglobulin; TgAb = Anti-thyroglobulin antibodies.