Role of cytological characteristics of benign thyroid nodules on effectiveness of their treatment with levothyroxine.
BACKGROUND
Levothyroxine (LT4) therapy has been used for the treatment of euthyroid nodular goiter, but there are controversial results about its usefulness. We aimed to evaluate the possible role of benign nodules' cytological characteristics in response to LT4 therapy.


METHODS
In total, 93 patients with 128 nodules were included in the study; 74 of the nodules were treated with LT4 (group 1), and 54 of them had no medication (group 2). The subgroups consisted of adenomatous nodules, colloid nodules and cystic nodules.


RESULTS
In group 1, mean thyroid volume and mean nodule volume were reduced significantly (p = 0.002 and p = 0.022, respectively) with low-normal level thyrotropin (TSH) suppression (between 0.3 mIU/ml and 1.0 mIU/ml), while there were no significant changes in group 2. When we evaluated changes of the initial and last nodule volumes in cytological subgroups, only colloid nodules in group 1 had significant reduction (p = 0.040) and the others had no significant changes. By omitting the colloid nodules, when the other nodules were revaluated, there were no significant changes in either group.


CONCLUSIONS
On the basis of these results, obtained from a large sample of Anatolian patients, it is possible that LT4 therapy leads to significant reductions of both thyroid volume and nodule size in colloid nodules, but not in other kinds of benign nodules.
Department of Endocrinology and Metabolic Diseases, Ankara Guven Hospital, Ankara, Turkey.
Mustafa
M
Cesur
Department of Statistics and Computer Science, Baskent University Faculty of Science and Letters, Ankara, Turkey.
Mehtap
M
Akcil
Department of Endocrinology and Metabolism, Medical Faculty, Ufuk University, Ankara, Turkey.
Sibel
S
Ertek
Department of Endocrinology and Metabolic Diseases, Ankara University School of Medicine, Ankara, Turkey.
Rifat
R
Emral
Department of Pathology, Ankara University School of Medicine, Ankara, Turkey.
Safak
S
Bulut
Department of Endocrinology and Metabolic Diseases, Ankara University School of Medicine, Ankara, Turkey.
Sevim
S
Gullu
Department of Endocrinology and Metabolic Diseases, Ankara University School of Medicine, Ankara, Turkey.
Demet
D
Corapcioglu
adenomatous nodule; colloid nodule; cystic nodule; cytological features; levothyroxine; levothyroxine suppressive therapy; nodule treatment; thyroid nodule