Safety and Efficacy of Recombinant Human Thyroid Stimulating Hormone for Adjuvant Diagnosis in Patients With Locally Advanced/Metastatic Differentiated Thyroid Cancer

This study is testing a lab-made version of a hormone (recombinant human TSH) to help doctors better detect and monitor thyroid cancer that has come back or spread after surgery, without requiring patients to stop their thyroid medication. **You may be eligible if...** - You are between 18 and 75 years old - You have differentiated thyroid cancer (a common, treatable type) and had your thyroid fully or mostly removed - Imaging or lab tests show that your cancer has returned locally or spread elsewhere - You have at least one measurable tumor - Your blood counts, kidney, and liver function are within acceptable ranges - Your general health is reasonably good (ECOG score 0–2) - Your expected survival is more than 3 months **You may NOT be eligible if...** - You have serious heart, liver, or kidney problems - You are pregnant or breastfeeding - You are allergic to the study drug - You have received certain other treatments recently Talk to your doctor to see if this trial is right for you.