Inclusion Criteria:

- Pathologically confirmed diagnosis of non-anaplastic non-medullary thyroid cancer
that is either grossly recurrent after surgery or unresectable with or without
metastatic disease.

- Age ≥18 years

- Karnofsky performance status ≥70%

- Patient has previously been treated with Radioactive Iodine

- Men and women of childbearing potential must be willing to consent to using effective
contraception while on treatment and for at least 3 months after treatment.

- Patients must have ability to understand and the willingness to sign a written
informed consent document.

Exclusion Criteria:

- Patients who will receive chemotherapy at the same time of EBRT for this cancer

- Women who are pregnant or lactating

- Inability to comply with study and/or follow-up procedures