Evolution of suppressing TSH therapy at diagnosis and in the long-term follow-up in a cohort of differentiated thyroid cancer.

Introduction: To evaluate the adequacy of TSH suppression therapy (TSHst) at the first disease assessment and the last follow-up visit.

Methods: Retrospective observational study of those patients under follow-up of DTC in a reference hospital.

Results: 216 patients (79.2% women) were evaluated, with a mean age 59.0 ± 13.1 years-old and a mean follow-up of 6.9 ± 4.3 years. 88.4% were papillary carcinomas. At diagnosis, 69.2% had a low risk of recurrence (RR) compared to 13.6% with a high RR. Dynamic risk stratification (DRS) classified patients at first disease assessment and the last visit as excellent response (ER) in 60.0% and 70.7%, respectively. Those patients with ER in the first and last follow-up control maintained TSHst in 30.7% and 16.3% of the cases, respectively (p < 0.001). The factors associated with maintaining TSHst at the last control were younger age, higher RR at diagnosis, DRE at follow-up, presence of multifocality and histological vascular invasion (p < 0.05). In a logistic regression analysis adopting tsTSH at follow-up as the dependent variable, exclusively age (β = -0.062; p < 0.001), RR at diagnosis (β = 1.074; p < 0.05) and EDR during follow-up (β = 1.237; p < 0.05) maintained statistical significance.

Conclusions: Despite the current recommendations, 30.7% of patients with low RR and initial ER are under TSHst. This percentage reduced to 16.3% in those patients with ER after a mean follow-up of 6.9 years. Age, baseline RR, and DRE during follow-up were associated to maintaining tsTSH.