However, even though thyroid cancer has a very good prognosis and most patients stay healthy after overcoming the disease, a recurrence (so-called relapse) cannot be ruled out.
Follow-up examinations are scheduled at regular intervals and the time period between these follow-ups will become longer over time, especially when there are no symptoms of recurrence and your doctor considers your risk of recurrence to be low. Your doctor will take into account the stage of your cancer at the time of diagnosis, the nature of your initial treatment and any follow up test results to assess your risk of recurrence over time.
When you visit your doctor, he or she will conduct a physical examination and might perform some of the following tests;
- Blood tests – to check your thyroid hormone and thyroglobulin (Tg) levels
- Ultrasound of your neck
- Imaging of the neck/body using X-rays or FDG-PET scan
- Whole body scan
Tg blood tests
Thyroglobulin (Tg) is a protein produced exclusively by thyroid cells so it’s a useful and important way to check that your cancer has been successfully treated.
Testing for Tg levels involves having a blood sample taken and tested in the lab. Follow up can involve testing while on hormone replacement therapy as well as having a stimulated Tg test performed. The stimulated Tg test requires high levels of TSH before performing the blood test. As with ablation, this can be achieved by means of hormone withdrawal or hormone replacement therapy with rhTSH.
This is a very sensitive way to find potential cancer in the thyroid. It involves moving an instrument along your neck; it is not painful and does not involve radiation exposure.
Whole body scan (scintigraphy)
Whole-body scanning is a diagnostic imaging technique which uses a special camera to create a physical picture of possible cancer cells in your body after you have swallowed a low dose of RAI. This can be done as part of your follow-up and is very similar to ablation itself. Except it involves much lower activities of radioactive iodine, and, thus, there’s no need to stay in the isolation ward.
Similar to when you had your ablation, the higher the TSH levels in the blood, the better any remaining cells will take up iodine. Therefore, you will need to either stop taking your thyroid hormone tablets for two to six weeks beforehand, or receive two injections of rhTSH.
Two days after ingestion of the low activity RAI, the whole-body scan is performed. Any visible areas of concentrated radiation show that you still have active thyroid cells. If this happens, your doctor will then perform further tests or wants to provide additional treatment with radioactive iodine.
Whole body scan is usually combined with stimulated Tg blood test.
PET scan or X-rays
If your doctor suspects your cancer may have spread, a PET scan or chest X-ray may be performed.