This is to adjust your dose of thyroid hormone tablets and to make sure that your cancer has been successfully treated. This can involve a number of tests and investigations, including;
- Palpation of the neck
- 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. After surgery and ablation, all thyroid cells should have been removed and therefore Tg values should become undetectable.
Testing for Tg levels involves having a blood sample taken and tested in the lab. In order to determine Tg values, it may be important to have high levels of TSH before performing the blood test. As with ablation, this can be achieved by means of hormone withdrawal or with rhTSH while taking hormone replacement therapy. In both cases, this is known as a stimulated Tg assay.
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
Whole-body scanning (scintigraphy) is a diagnostic imaging technique which uses a special camera to create a physical picture of cancer cells in your body, if any exist, after you have swallowed RAI. This can be done as part of your follow-up visit after ablation and is very similar to ablation itself, except that it involves much lower activities of radioactive iodine, and, thus, there’s no need to stay in the isolation ward. It is usually done in combination with a stimulated Tg test (see chapter Tg blood tests above).
Similar to when you had your RAI ablation, the higher the TSH level in your blood, the better any remaining thyroid 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 injections of rhTSH.
Two days after taking radioactive iodine, 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 perform further tests or wants to provide additional treatment with radioactive iodine.
PET scan or X-rays
If your doctor suspects your cancer may have spread, a PET scan or chest X-ray may be performed.
After treatment, it is normal to feel physically and mentally drained. Psychological support can be a helpful complement to the care you receive from your doctor and you may find it useful to get additional support from other cancer support groups. Contact with others who suffer or who have had thyroid cancer - via local support groups for instance - can be a great help, since they will know what you are going through and can therefore lend very practical advice and help. Your doctor might also be aware of local resources for psychological support.
The aim of initial therapy is to eradicate all residual thyroid cells through surgery and ablation, in order to reduce the risk of local and distant tumour recurrence, which could prolong survival. Ablation increases the sensitivity of any necessary subsequent iodine scanning and subsequent Tg monitoring, which helps your doctor to be sure that the thyroid cancer has been fully destroyed when you come back for follow up.