Radiation therapy and radioactive iodine therapy may be part of your treatment plan depending on the type of thyroid cancer you have. Our specialists at Fred Hutch Cancer Center will explain why certain therapies can be an option for you.

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How Radiation Therapy is Used for Thyroid Cancer Treatment

External Radiation Therapy

External radiation therapy uses a machine outside the body to send radiation beams to the area of the body with cancer. It is most often used for cancers that have spread outside of the thyroid. This therapy to the neck area is usually given five days a week for several weeks.

External radiation therapy might be done to help treat the cancer, to treat symptoms such as pain or to help lower the chance of cancer coming back after surgery. It is most often used to treat medullary thyroid cancer or anaplastic thyroid cancer because these cancers don’t take up iodine.

Internal Radiation Therapy

This is a type of radiation therapy where a source of radiation is put inside the body. It uses a radioactive substance sealed in needles, wires, seeds or catheters that are placed into or near the cancer in the body.

How Radioactive Iodine Therapy is Used for Thyroid Cancer Treatment

Your thyroid gland absorbs nearly all the iodine that enters your body. Because of this, radioactive iodine (RAI, also called iodine-131 or I-131) can be used to treat papillary or follicular thyroid cancers. It can be used to:

  • Destroy any remaining thyroid tissue, if surgery can’t remove it all.
  • Try to destroy any remaining thyroid tissue that can’t be seen, especially if there’s a higher risk of the cancer coming back. This is done after surgery, as an additional treatment.
  • Treat some thyroid cancers that have spread to lymph nodes or other parts of the body.

Radioactive iodine can often help treat papillary or follicular thyroid cancer that has spread to the neck or other parts of the body. But the benefits are less clear for people with small cancers of the thyroid gland that do not seem to have spread, which can often be removed completely with surgery.

Radioactive iodine therapy isn’t used to treat anaplastic or medullary thyroid cancers because these types of cancer do not take up iodine.

Dr. Delphine Chen
Dr. Delphine Chen is the director of Molecular Imaging and Therapy at Fred Hutch.

Why Choose Fred Hutch for Radiation and Radioactive Iodine Therapies for Thyroid Cancer

Radiation oncologists at Fred Hutch are experts in all forms of radiation therapy to treat cancer. They know how to choose and combine options to match your needs. Besides standard therapies, we often have clinical trials testing new drugs or new combinations for thyroid cancer. Through these clinical trials, we are able to offer therapies that aren’t offered everywhere.

Your radiation oncologist partners with the rest of your Fred Hutch care team. They work closely with your surgical oncologist (if surgery is needed) and pathologist. They design a treatment plan to target your tumor and have the least impact on healthy tissue. Your radiation oncologist also works closely with you to manage any side effects from radiation treatments. Your whole team helps you take the best possible care of yourself.

Radiation and Radioactive Iodine Therapies for Thyroid Cancer FAQ

External radiation therapy to the neck area is usually given five days a week for several weeks.

Before your treatments start, your medical team will take careful measurements to find the proper dose of radiation and the correct angles for aiming the radiation beams.

The treatment itself is painless and is similar to getting a regular X-ray. Each treatment lasts only a few minutes, although the setup time (getting you into place for treatment) usually takes longer.

In radioactive iodine therapy, you swallow a capsule that has a special radioactive type of iodine called I-131. As the capsule melts, the radioactive iodine moves through your bloodstream and collects in your thyroid cells, which destroys the thyroid cells along with the cancer cells.

Common side effects of external radiation therapy for thyroid cancer include:

  • Fatigue
  • Hair loss
  • Mouth problems
  • Skin changes
  • Taste changes
  • Throat problems, such as trouble swallowing
  • Change in hormone levels

If your Fred Hutch care team recommends external radiation therapy, we’ll explain what to expect based on the medicine you’re getting and how to manage these side effects.

Your care team at Fred Hutch is here to help you prevent or prepare for side effects and to relieve any side effects you have. The most important step you can take is to speak up and let your team know what you’re feeling. We’ve helped many patients and families through this process and know ways to ease your experience. The Fred Hutch Patient Education team has video resources that go over how to keep common side effects at bay.

Often, there are medicines to help, like anti-nausea drugs. Based on the side effect, there may be a range of other helpful options too, like diet changes, physical therapy and emotional and practical support. We also offer integrative medicine, including acupuncture.