RW Study of Adjuvant Radiotherapy in Locally Advanced Thyroid Cancer

This study is examining how well adjuvant radiation therapy (radiation given after surgery) works in patients with locally advanced thyroid cancer who are at high risk of the cancer coming back. Researchers are collecting real-world data to better understand outcomes for these patients. **You may be eligible if...** - You are between 14 and 80 years old - You have a confirmed thyroid cancer diagnosis (including differentiated, medullary, or poorly differentiated types) - You are at high risk of local recurrence — for example, because surgery could not fully remove the cancer (not R0 resection), the cancer invaded nearby structures (esophagus, trachea, nerves), or you had a poor-prognosis cancer type **You may NOT be eligible if...** - Your thyroid cancer has not yet been surgically treated (only biopsied) - You have had or currently have another active cancer within the past 5 years (some cured local cancers may be acceptable) - You previously received radiation to your head or neck - You are pregnant or breastfeeding - You have claustrophobia preventing you from tolerating radiation therapy - Other serious illnesses or conditions make participation unsafe Talk to your doctor to see if this trial is right for you.