Among people who have thyroid nodules, only about 5 percent of thyroid nodules are cancerous. Thyroid cancers need to be removed by surgery, after which radioactive iodine therapy may be needed to destroy any remaining thyroid cells. Following surgery and subsequent radioactive iodine therapy, patients with thyroid cancer require monitoring for many years.
The monitoring varies among patients but typically includes tests for thyroid function and serum thyroglobulin levels (a tumor marker), as well as possibly radiologic studies to include sonograms, CT scans, MRI scans and radioactive scans. The tests will vary based on the type of tumor.