1636 - A prospective study of subacute thyroid dysfunction following supraclavicular irradiation in the management of carcinoma of the breast

Date 28 September 2012
Event ESMO Congress 2012
Session Publication Only
Topics Complications of Treatment
Breast Cancer
Presenter Serap Akyurek
Authors S. Akyurek1, I. Babalioglu1, S. Yuksel2, S. Cakir Gokce1
  • 1Radiation Oncology, Ankara University School of Medicine, 06100 - Ankara/TR
  • 2Biostatistic, Ankara University School of Medicine, Ankara/TR

Abstract

Purpose

To evaluate the relationship between irradiation and early thyroid dysfunction, focusing on radiation dose-volume factors.

Patients and methods

Between December 2010 and January 2012 a total of 21 patients with breast cancer received supraclavicular irradiation were evaluated Thyroid function tests, including serum thyroid stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), were analyzed prior to irradiation and every three months the first year and then 18th month after radiotherapy. Based on each patient's dose volume histogram (DVH), total volume of the thyroid, mean radiation dose the thyroid and percentages of thyroid volume which received radiation doses 10-60Gy (V10-V60) were considered for statistical analysis.

Results

Mean TSH levels before irradiation, at 3, 6, 9 and 12 months were 1.4 µIU/ml, 1.5 µIU/ml, 1.7 µIU/ml, 3.6 µIU/ml and 4.6 µIU/ml, respectively. Serum TSH levels did not change significantly at 3 and 6 months after irradiation (p = 0.1). However, a significant elevation was noted at 9 months (p = 0.005). Mean thyroid dose was 32 Gy (19-48 Gy) and mean thyroid volume was 35 cc (24-64 cc). Median values of V10-20-30-40-50-60 were 68%, 58%, 55%, 53%, 48% and 0%, respectively. With a median follow-up was 9 months (range, 3-18 months), only one patient (5%) developed clinical hypothyroidism requiring thyroid replacement treatment.

Conclusion

According to early results of our study, irradiation of the thyroid develops early thyroid dysfunction. This damage is initially manifested within 9 months after radiotherapy. However we could not analyze the radiation dose-volume factors of the peak level of serum TSH because of inefficient follow up time.

Disclosure

All authors have declared no conflicts of interest.