The Efficacy of Thyrotropin Suppression Therapy in Treatment of Differentiated Thyroid Cancer after Total Thyroidectomy

Background: The aim of this prospective study was to assess the effect of the TSH suppression on both disease-free and overall survivals in patients with nonmetastatic differentiated thyroid cancer (DTC) after total thyroidectomy.

Patients & Methods: One hundred and forty eight patients with pathologically proved operable differentiated thyroid carcinoma were enrolled in this prospective study. Levothyroxin (L-T4) therapy was started in doses according to treatment groups. Patients were randomly assigned to receive either postoperative TSH suppression therapy in group I (76 patients) or nonsuppression therapy in group II (72 patients).

Results: During the period of follow up with a median 54 months, the disease-free survival for patients without TSH suppression therapy did not reach statistically significant difference comparing with those for patients with the suppression therapy (p=0.09). However, the difference was statistically significant for high-risk patients (p=0.04). On comparing both groups there was no statistically significant difference with regard to overall survival (p=0.17). The age of the patients more than 45 years, tumour size more than 4 cm and high-risk group were significant independent predictors for thyroid carcinoma-related relapse in univariate analysis. However, tumour size was the only significant factor in multivariate analysis.

Conclusion: Suppressive treatment with L-T4 therapy in patients with differentiated thyroid carcinoma should be individualised and balanced against the adverse effects. TSH suppression is indicated in patients with high-risk disease or recurrent tumour. Normalisation of serum TSH is preferred for long-term treatment of disease-free elderly patients with DTC and comorbidities.