Have a patient with a multi-year history of a growing substernal goiter. There is mass effect on the trachea, esophagus, and aorta. He is experiencing intermittent dysphagia. Multiple tertiary centers declined to operate. 150 mCI RAI administered with minimal effect on size or symptoms. Is there a role for EBRT here? Seems to make sense radiobiologically, but there is little data to go on.