[Suppressive thyroxine therapy of differentiated thyroid cancer in daily practice of a large cancer centre].

Introduction: The study summarizes the results of an audit evaluating the realization of the suppressive TSH therapy in patients with differentiated thyroid cancer.

Material And Methods: The evaluation was performed in 500 consecutive patients.

Results: In patients in whom remission was diagnosed < 5 years ago, in 70% subcomplete suppression was stated (TSH 0.1-0.3 mU/L) and complete suppression (TSH < 0.1 mU/L) was observed in 20%. Unexpectedly in patients in whom remission lasted > 5 years, complete suppression was observed in 60%. However, this last group was less numerous, thus, the majority of no evidence of disease patients exhibited subcomplete TSH suppression, while only 40% of patients with active disease had this goal realized.

Conclusions: 1. Iatrogenous hypothyroidism was well controlled in nearly all differentiated thyroid cancer patients. 2. The goal of L-thyroxine treatment, defined as TSH serum level < 0.4 mU/L was achieved in 90% of them without a significant risk of iatrogenous thyrotoxicosis. 3. Some overdosage of L-thyroxine was observed, especially in patients in whom remission lasted > 5 years. It this group of patients there is no reason to induce full suppression of TSH by L-thyroxine treatment.