Evaluation of clinical hypothyroidism risk due to irradiation of thyroid and pituitary glands in radiotherapy of nasopharyngeal cancer patients

Zhixiong Lin, Xiaoyan Wang, Wenjia Xie, Zhining Yang, Kaijun Che, Wing Cheung Vincent Wu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

16 Citations (Scopus)

Abstract

Introduction Radiation-induced thyroid dysfunction after radiotherapy for nasopharyngeal cancer (NPC) has been reported. This study investigated the radiation effects of the thyroid and pituitary glands on thyroid function after radiotherapy for NPC. Methods Sixty-five NPC patients treated with radiotherapy were recruited. Baseline thyroid hormone levels comprising free triiodothyronine (fT3), free thyroxine (fT4) and thyroid-stimulating hormone (TSH) were taken before treatment and at 3, 6, 12 and 18 months. A seven-beam intensity-modulated radiotherapy plan was generated for each patient. Thyroid and pituitary gland dose volume histograms were generated, dividing the patients into four groups: high (>50 Gy) thyroid and pituitary doses (HTHP group); high thyroid and low pituitary doses (HTLP group); low thyroid and high pituitary doses; and low thyroid and pituitary doses. Incidence of hypothyroidism was analysed. Results Twenty-two (34%) and 17 patients (26%) received high mean thyroid and pituitary doses, respectively. At 18 months, 23.1% of patients manifested various types of hypothyroidism. The HTHP group showed the highest incidence (83.3%) of hypothyroidism, followed by the HTLP group (50%). Conclusions NPC patients with high thyroid and pituitary gland doses carried the highest risk of abnormal thyroid physiology. The dose to the thyroid was more influential than the pituitary dose at 18 months after radiotherapy, and therefore more attention should be given to the thyroid gland in radiotherapy planning.
Original languageEnglish
Pages (from-to)713-718
Number of pages6
JournalJournal of Medical Imaging and Radiation Oncology
Volume57
Issue number6
DOIs
Publication statusPublished - 1 Dec 2013

Keywords

  • head and neck
  • hypothyroidism
  • nasopharyngeal carcinoma
  • radiation oncology

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Oncology

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