Thyroid Cancer (cont.)

Thyroid hormone treatment

After surgery to remove part or all of the thyroid, most people need to take pills to replace the natural thyroid hormone. However, thyroid hormone pills are also used as part of the treatment for papillary or follicular thyroid cancer. Thyroid hormone slows the growth of thyroid cancer cells left in the body after surgery.

Although thyroid hormone pills seldom cause side effects, too much thyroid hormone may cause you to lose weight and to feel hot and sweaty. Too much thyroid hormone may also cause a fast heart rate, chest pain, cramps, and diarrhea. Too little thyroid hormone may cause you to gain weight, feel cold and tired, and have dry skin and hair. If you have side effects, tell your doctor. Your doctor can give you a blood test to make sure you're getting the right dose of thyroid hormone.

You may want to ask the doctor these questions before taking thyroid hormone:

  • Why do I need this treatment?
  • What will it do?
  • How long will I be on this treatment?

Radioactive iodine therapy

Radioactive iodine therapy with I-131 is a treatment for papillary or follicular thyroid cancer. It kills thyroid cancer cells and normal thyroid cells that remain in the body after surgery.

People with medullary or anaplastic thyroid cancer usually do not receive I-131 therapy. These types of thyroid cancer rarely respond to I-131 therapy.

For one or two weeks before treatment, you will need to be on a special diet. Avoid fish (especially shellfish), seaweed, iodized salt, milk, yogurt, ice cream, bacon, ham, and other foods with iodine. Do not take vitamin pills or drugs that have iodine.

Because some imaging tests (such as CT scans) use iodine in the contrast material, tell your doctor if you had a CT scan or other imaging test in the past 6 months.

For the treatment, you will swallow one or more capsules or a liquid that contains I-131. Even people who are allergic to iodine can take I-131 therapy safely. I-131 goes into the bloodstream and travels to thyroid cancer cells throughout the body. When thyroid cancer cells take in enough I-131, they die.

Many people get I-131 therapy in a clinic or in the outpatient area of a hospital and can go home afterward. Other people have to stay in the hospital for one day or longer.

Most radiation from I-131 is gone in about one week. Within three weeks, only traces of radiation remain in the body.

During treatment, you can help protect your bladder and other healthy tissues by drinking a lot of fluids. Drinking fluids helps I-131 pass out of the body faster.

Some people have mild nausea the first day of I-131 therapy. A few people have swelling and pain in the neck where thyroid cells remain. If thyroid cancer cells have spread outside the neck, those areas may be painful too.

You may have a dry mouth or lose your sense of taste or smell for a short time after I-131 therapy. Gum or hard candy may help.

A rare side effect in men who receive a high dose of I-131 is loss of fertility. In women, I-131 may not cause loss of fertility, but some doctors advise women to avoid getting pregnant for one year after a high dose of I-131.

Researchers have reported that a very small number of patients may develop a second cancer years after treatment with a high dose of I-131. See the Follow-up Care section for information about checkups after treatment.

Because a high dose of I-131 also kills normal thyroid cells, you'll need to take thyroid hormone pills after this treatment to replace the natural hormone.

You may want to ask the doctor these questions before having I-131 therapy:

  • Why do I need this treatment?
  • What will it do?
  • How do I prepare for this treatment? Which foods and drugs should I avoid? For how long?
  • Will I need to stay in the hospital for this treatment? If so, for how long?
  • How do I protect my family members and others from the radiation? For how many days?
  • Will I-131 therapy cause side effects? What can I do about them?
  • What is the chance that I will be given I-131 therapy again in the future?

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Thyroid Cancer - Symptoms Question: The symptoms of thyroid cancer can vary greatly from patient to patient. What were your symptoms at the onset of your disease?
Thyroid Cancer - Treatments Question: What was the treatment for your thyroid cancer?
Thyroid Cancer - Share Your Surgery Experience Question: Please share your experience with surgery for thyroid cancer.