The Effect of Somatostatin Analogue Treatment on Thyroid Gland in Acromegaly Patients

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 88-129-Acromegaly & Prolactinoma
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-110
Yasemin Tutuncu*1, Kerim Kucukler1, Dilek Berker1, Serhat Isik1, Gulhan Akbaba1, Ufuk Özuguz1 and Serdar Guler2
1Ankara Numune Training and Research Hospital, Ankara, Turkey, 2Hitit University Faculty of Medicine, Corum, Turkey
Aim: In general, surgery is the first line treatment for acromegaly, however somatostatin analogues can be added to the treatment in patients who cannot be cured by surgery. The expression of somatostatin receptors 1,2,3 and 5 have been demonstrated in normal thyroid gland. And it was found that somatostatin analogues may lead to reduced thyroid gland due to their antiproliferative and IGF-1 reducing effects. However, there is no literature on their effect on thyroid nodules and thyroid functions. Thus, we designed this study to examine the effects of somatostatin analogues on the volume of thyroid gland, thyroid nodules and thyroid functions in acromegaly.

Material and Methods: A retrospective screening was carried out in records of 108 patients who were monitored at the Endocrinology and Metabolism Diseases Clinic of Ankara Numune Training and Research Hospital for a diagnosis of acromegaly. The study included a study group of 35 patients who were initiated on somatostatin analogues due to lack of cure after the surgery, and a control group of 21 patients who received surgical treatment and did not require any medical treatment. One year after biochemical remission of patients in both groups, we assessed levels of thyroid stimulating hormone (TSH), free triiodothyronine (sT3), free thyroxine (sT4), anti-thyroid peroxidase antibodies (antiTPO) and antithyroglobulin antibodies (antiTG), and thyroid volumes and thyroid nodule volumes.

Results: Mean age and sex ratio was similar in both groups (p=0.05; p=0.2). Seventeen of the patients in the group of medical treatment received Octreotid (49%), and 18 used Lanreotid (51%). No statististical difference was found between the groups in pre-treatment levels of TSH, sT3, GH, IGF-1, and thyroid volume and number of nodules. However, initial nodule volume was smaller in the control group than in the study group (p=0.032).

There was no statistical difference between the groups in post-treatment levels of TSH, sT3,sT4, GH, and IGF-1 and nodule volume. After 1-year follow-up, total thyroid volume was lower in the study group compared to the control group ( p=0.045).

A statistically significant reduction was observed in the initial and 1-year follow-up thyroid volumes in both patients who received Octreotid and Lanreotid in the study group, however no difference was found between the two drugs.

Conclusion: Treatment of acromegaly, whether  it is surgical or medical, resulted in regression in the thyroid volume, however the effect of treatment with somatostatin analogues on the thyroid volume was greater. This statistically significant reduction may be explained by the expression of receptors S1,2,3 and 5 in the thyroid parenchyma. We suggest that absence of any post-treatment difference in nodule volumes may result from the fact that somatostatin receptors are located particularly in the thyroid parencyhma rather than the nodule.

Nothing to Disclose: YT, KK, DB, SI, GA, U, SG

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