Role of radiotherapy in differentiated thyroid cancer

Abstract

Differentiated thyroid cancers (i.e. papillary or follicular) account for majority of thyroid malignancies. Even though surgery has been the mainstay for these tumors, use of radioactive iodine (I131) therapy and thyroid hormone replacement therapy is common in most of these tumors in adjuvant setting. Radiotherapy is indicated in the presence of, gross residual disease after surgery, extra-capsular extension, and extensive lymph node involvement. As thyroid gland is located at the root of neck, sometimes with retrosternal extension and surrounded by critical structures, it is difficult to adequately cover the entire target volume with conventional radiotherapy technique. IMRT is a useful technique in these tumors, since it provides good dose distribution along with sparing of spinal cord while treating thyroid bed in adjuvant setting, and therefore it needs to be further standardized. Additionally palliative radiotherapy is effective in brain and bone metastasis. To conclude, external beam radiotherapy is an established and effective mode of therapy both in curative and palliative settings.