Is TSH suppression still necessary in intermediate- and high-risk papillary thyroid cancer patients with pre-ablation stimulated thyroglobulin <1 ng/mL before the first disease assessment?

objectiveSince papillary thyroid cancer (PTC) patients with pre-ablation stimulated thyroglobulin (s-Tg) < 1 ng/mL generally have a favorable prognosis, is TSH suppression still necessary in intermediate- and high-risk PTC patients with pre-ablation s-Tg < 1 ng/mL after initial therapy? The aim of this study was to assess the rate of disease recurrence in intermediate- and high-risk PTC patients with pre-ablation s-Tg < 1 ng/mL according to TSH levels measured 1 year after initial therapy.

methodsA retrospective series of intermediate- and high-risk PTC patients with pre-ablation s-Tg < 1 ng/mL was analyzed. Disease status was defined as the presence or absence of structural disease during late follow-up. Patients were grouped according to TSH level at 1 year: group 1, TSH < 0.1 mIU/L; group 2, TSH 0.1‒0.5 mIU/L; group 3, 0.5‒2 mIU/L; group 4, >2 mIU/L.

resultsThis study included 166 patients (78.3% females, median age 44 years) of whom the risk of recurrence was intermediate in 97 (58.4%) and high in 69 (41.6%). The response to initial therapy at 1 year was excellent in 163 patients (98.2%) and indeterminate in 3 (1.8%). Group 1 consisted of 63 patients (38%), group 2 of 47 (28%), group 3 of 28 (17%), and group 4 of 28 (17%). During a median follow-up duration of 5.8 years, disease recurrence was observed in only 4 patients (2.4%). The rate of disease recurrence was not significantly different between the TSH groups.

conclusionTSH suppression before the first response to treatment assessment does not seem to influence the rate of disease recurrence after initial therapy in intermediate- and high-risk PTC patients with pre-ablation s-Tg < 1 ng/mL.