External beam radiotherapy in differentiated thyroid carcinoma: A systematic review

External beam radiotherapy (EBRT) is not a first line treatment in differentiated thyroid carcinoma (DTC), but is recommended as an adjuvant treatment in certain cases. The evidence for EBRT in DTC is limited. A comprehensive literature search was performed. Data on patient demographics, disease stage, treatment characteristics, and outcomes were collected from included articles after quality appraisal. Sixteen articles met the inclusion criteria, with a pooled population of 5114. Only 1 study was prospective and there were no randomized controlled trials. Most of the evidence suggests that EBRT improves locoregional control in patients at high risk of locoregional recurrence. This was corroborated by analysis of pooled patient data. Available evidence suggests an improvement in locoregional control when EBRT is used in patients over the age of 45 at high risk for locoregional recurrence. However, there is a need for long-term prospective multicenter research on the subject. © 2015 Wiley Periodicals, Inc. Head Neck 38: E2297-E2305, 2016.