The role of external beam radiation and targeted therapy in thyroid cancer.

The initial management of thyroid cancer is usually surgery, followed by radioactive iodine in differentiated thyroid cancer. The role of external beam radiotherapy for gross residual or unresected disease is discussed. For both differentiated thyroid cancer and medullary thyroid cancer, the role of external beam radiotherapy after resection of gross disease when there is a high risk of local regional failure is reviewed. In anaplastic thyroid cancers, although most patients present with unresectable disease and radiotherapy is the mainstay of treatment, the benefits of the addition of chemotherapy to radiation therapy will be discussed. Patient selection, radiation volumes, and radiation doses will be discussed. As in other tumor sites, external beam radiation has an import role in the palliative management of patient with metastatic thyroid cancer of all histologies, especially of metastases to bone but also brain and lung, but this role is not described in the review.