After radioiodine therapy, some people get swelling of the salivary glands in the cheeks or neck. This is a temporary effect and is usually treated with anti-inflammatory medicines such as ibuprofen (Advil, Motrin) for a few days. Also, sometimes people are taken off the thyroid hormone medication and made hypothyroid (low thyroid) before treatment. This helps the radioiodine treatment to be more effective. In these cases, people will often feel tired, cold and achy. As soon as the treatment dose is given, the thyroid hormone is restarted and the symptoms will go away.
The side effects of chemotherapy and radiation therapy are well known and can be troublesome. However, these treatments are rarely used for thyroid cancer. If your doctor recommends chemotherapy or radiation therapy, you should ask about side effects before beginning.
If you are enrolled in a clinical trial, side effects of the new agents may not be well known. In these cases, if you begin developing strange or unusual symptoms, you should contact your study coordinator or doctor at once to get advice on what steps, if any, need to be taken. This is also important because it helps the manufacturers of the new drugs know if the agents are safe.