Thyroid hormone therapy

If your thyroid gland has been removed you will need thyroid hormone therapy to replace the thyroid hormone.

Taking thyroid hormone also reduces the amount of thyroid-stimulating hormone (TSH) in your body, which can stop any surviving thyroid cells from working and help to prevent the cancer coming back. 

Thyroid hormone replacement 

You will be given the replacement drug for life, usually thyroxine, which is also called T4.

Without these hormones you would develop signs and symptoms of an underactive thyroid. This is called hypothyroidism. Signs of it include weight gain, tiredness, dry skin and hair, and physical and mental slowness.

Most people only need to take the drug once a day but at the same time. It may take some months to find the correct dosage for you. As a result, you will have blood tests to check your hormone levels regularly. 

TSH supression

Taking thyroid hormone can keep TSH levels very low. This can prevent thyroid cancer developing. You may be given thyroid hormone if only part of your thyroid gland is removed. TSH will be kept low for at least 1 year after radioactive iodine therapy or until you complete the surveillance testing.

What are the side-effects of thyroid hormone therapy treatment? 

• Too much thyroid hormone:  Weight loss, and feeling hot and sweaty, a fast heart rate, chest pain, cramps and diarrhoea. In the long term, it can cause weak bones (osteoporosis). 
• Too little thyroid hormone: Weight gain, feeling cold and tired, and dry skin and hair. 

If you have any side-effects, do tell your doctor or nurse. Your doctor can do a blood test to make sure you are getting the right dose of thyroid hormone.