Radiotherapy-Induced Structural and Functional Changes in the Thyroid Gland

Author(s): Mai Elzahry, Mohamed Wahman

Background: Despite their specific functional hazards, radiotherapy induced thyroid disorders remain under-evaluated, even though, various types of irradiation caused either benign and malignant changes of the thyroid gland have been mentioned in this study.

Aim: To report the current status concerning the hazards of various types of irradiation on the detection of different thyroid abnormalities either benign and/or malignant changes.

Materials and Methods: This is a retrospective clinical study on 40 cancer patients received irradiation between July 2011 and July 2016. 14 (35%) males and 26 (65%) females, their age range (33-80y, mean ± SD=56.5 ± 11.8). After the completion of treatment, all patients were seen at 6 weeks then every 4–6 months for first 5 years. Due to the study, full thyroid gland assessment was performed (clinical examination, lab investigations, thyroid U.S and biopsy for malignant thyroid.

Results: After full clinical and anatomical assessment of the thyroid gland abnormalities in all 40 cancer patients received a variable doses of radiotherapy, we found that 40% of the patients showed multinodular goiter, 22.5% showed thyroiditis and 37.5% showed differentiated cancer thyroid (25% papillary,12.5% follicular cancer) proved later by biopsy from the gland. The incidence of malignant thyroid diseases increased significantly among the older patients received high radiation doses(>50Gy) over long post-therapy follow up.

Conclusion: Various thyroid gland disorders may result after radiation exposure. There are a Little literatures report the true incidence, causes and risk factors of these disorders. Patients age and high radiation dose(>50Gy) has an account for the occurrence of malignant thyroid diseases.