Treatment Side Effects of Thyroid Cancer

Side Effects Management

It helps to learn more about the side effects of treatment(s) before you begin, so you will know what to expect. When you know more, you can work with your health care team to manage your quality of life during and after treatment.

There are effective medications to address traditional side effects from cancer treatment such as nausea, diarrhea, constipation and mouth sores.

Keep in mind that everyone reacts differently to treatment and experiences side effects differently. There are coping mechanisms and strategies that can help.

Common Side Effects From Treatment


After surgery, most people need pills for the rest of their life to replace lost thyroid hormones. If the parathyroid glands are also removed, calcium and vitamin D pills may also be needed.

Thyroid Hormone Treatment

Thyroid hormone pills do not usually cause side effects but uneven hormone levels may. Too much thyroid hormone may increase heart rate, cause weight loss, chest pain and cramps. Too little may cause weight gain, fatigue and dry skin and hair. Doctors monitor proper hormone levels through blood tests.

Radioactive Iodine Therapy

Side effects from radioactive iodine include: mild nausea during the first day, swelling and pain in the neck where thyroid cells remain and dry mouth. Rarely, men receiving high doses can lose fertility. Women are advised against getting pregnant for one year after a high dose. High doses also kill normal thyroid cells so thyroid hormone pills may be needed.

External Radiation Therapy

Side effects depend on the dose. Radiation to the neck may cause a dry, sore mouth and throat, hoarseness, difficulty swallowing and fatigue.


Chemotherapy has different side effects depending on the type and dose of drugs given and the length of time they are taken. These side effects can include hair loss, mouth sores, loss of appetite, nausea and vomiting, diarrhea, increased chance of infections (due to low white blood cell counts), easy bruising or bleeding (due to low blood platelet counts) and fatigue (due to low red blood cell counts).