Comparison of the Influence on the Liver Function Between Thyroid Hormone Withdrawal and rh-TSH Before High-Dose Radioiodine Therapy in Patients with Well-Differentiated Thyroid Cancer.

PURPOSE

An elevated thyroid stimulating hormone level (TSH) is essential to stimulate the uptake of radioiodine into thyroid remnants and metastases of thyroid cancer when a patient undergoes high-dose radioiodine therapy. Nowadays, recombinant human thyroid stimulating hormone (rh-TSH) is increasingly used instead of the classic method of thyroid hormone withdrawal (THW). However, beyond the therapeutic effects, clinical differences between the two methods have not yet been clearly demonstrated. The aim of this work was to investigate the effects of the two methods, especially on liver function.

METHODS

We identified 143 evaluable patients who were further divided into two groups: THW and rh-TSH. We first reviewed the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels, which were measured during the admission period for total thyroidectomy. We called these liver enzyme levels "base AST" and "base ALT." We also assessed other chemistry profiles, including AST, ALT, total cholesterol, LDL cholesterol, alkaline phosphatase (ALP), total bilirubin (TB), and triglyceride (TG), which were measured on admission day for high-dose radioiodine therapy. We called these liver enzyme levels "follow-up AST" and "follow-up ALT." We compared the changes in base and follow-up liver enzyme levels and the other chemistry profiles between the two groups.

RESULTS

The base AST and base ALT levels of the two groups were within normal range, and there was no significant difference between the two groups. In contrast to these base liver enzyme levels, follow-up liver enzyme levels between the two groups showed significant differences. Patients in the THW group had higher follow-up AST and ALT levels than did the rh-TSH group. Patients in the THW group also had higher levels of total cholesterol and LDL cholesterol than did the patients in the rh-TSH group. However there were no statistically significant differences in ALP, total bilirubin, and triglyceride levels between the two groups.

CONCLUSIONS

In this retrospective analysis of liver function, the use of rh-TSH for high-dose radioiodine therapy had less of an effect on liver function and cholesterol levels than dose thyroid hormone withdrawal. This suggests that rh-TSH can be used effectively and safely especially for patients with metabolic syndrome.