Trial Information

Levothyroxine Treatment in Thyroid Benign Nodular Goiter

OBJECTIVE - Current treatment of benign thyroid is oral levothyroxin by suppression of
thyrotropin secretion and so that tumor growth. Although current consensus is taking
thyroxin one hour before meal because the PH value of gastrointestinal tract will affect
drug absorption, some patient suffered from epigastric discomfort when taking thyroxin with
empty stomach, and wish to take it postprandial. However, there is no direct evidence
showing if taking thyroxin at different time point significantly affects treatment outcome.
Besides, the response to thyroxin therapy differs among people. The purposes of this study
are to evaluate the clinical significance of different time points of thyroxine intake and
to search factors relating to thyroxin response of benign thyroid tumors.

RESEARCH DESIGN AND METHODS - We will include patients who have benign thyroid tumors
diagnosed with fine needle aspiration cytology and have normal thyroid function into our
study. After informed consent, patients will be randomly assigned into two groups. Patients
in the first group will take thyroxin one hour before breakfast until thyrotropin level
stabilized between 0.5 and 1.0 mU/L for 3 months. Then thyroxin will be discontinued.
Patients will restart thyroxin therapy three months later but after breakfast. Patients in
another group will take thyroxin postprandial, discontinue thyroxin and then one hour before
breakfast. Questionnaire interviews about diet and life style, blood samples and fine needle
aspiration cytology samples will be obtained. Changes of thyroid nodules will be evaluated
with thyroid echo.

STATISTIC ANALYSIS - Descriptive data will be described as means and SDs for continuous
variables, and analysis of variance and Chi-square tests were used for assessing the
significances. A p-value below 0.05 was considered significant.

Keywords: benign thyroid tumor, thyroxin, preprandial, postprandial.