Radiotherapy-induced Thyroid Disorders: Review And Perspectives

The thyroid gland is the largest pure endocrine organ in the body, but also easy to damage the radiation therapy of the organs, with the improvement of radiotherapy, the survival time of patients, thyroid damage caused by radiation therapy more and more clinical attention. Radioactive thyroid damage include: hypothyroidism, hyperthyroidism, thyroiditis, GRAVES 'disease, thyroid adenoma, goiter, and thyroid cancer. Radiation dose to the thyroid that close to 26Gy, the primary hypothyroidism is the most common, occurring in approximately 20% -30%, more than half occurred in the 5 years after treatment. When the pituitary region receives doses over 50Gy, the incidence of central hypothyroidism will increase. In the long-term survival of cancer patients in the incidence of thyroid cancer is 15-53 times the general population, about 0.35% (but more than 90% of well differentiated histological type), treatment with increasing age, the incidence decreased. Thyroid damage assessment system is more the application of LENT / SOMA , and its etiology, including: hypothalamus - pituitary dysfunction, thyroid substantial cell damage caused by radiation therapy of autoimmune response. The location of the tumor, the total radiation dose received by radiation therapy of thyroid volume and thyroid resection is an important factor in causing thyroid damage. Others such as patient age, tumor stage, chemotherapy, endocrine therapy, radiotherapy methods and the relationship between thyroid injury remains controversial. In the course of radiotherapy to reduce the thyroid and hypothalamus - pituitary axis of the radiation dose and irradiated volume should be of concern. The new radiotherapy methods, such as three-dimensional conformal radiotherapy, intensity modulated radiotherapy better able to protect normal tissue. The diagnosis was the determination of serum TSH and FT4. After radiotherapy, periodic clinical and laboratory evaluation to avoid excess morbidity. Hypothyroidism mainly hormone replacement therapy, the treatment of thyroid injury is similar to other primary diseases.