Treatment options for thyroid cancer

A plain-language guide to active surveillance, thyroid surgery, radioactive iodine, thyroid hormone pills, radiation and targeted drugs, and how your team chooses.

6 min read · last reviewed September 30, 2026

Once you know you have thyroid cancer, the next big question is, "What happens now?" The good news is that thyroid cancer has well-tested treatments, and most people have a clear plan.

Your plan depends on the type of thyroid cancer you have, its size and stage, how likely it is to come back, and what matters most to you. Your team will tailor it to you. Here is an overview of the main options.

Active surveillance: watching closely

For some very small, low-risk papillary cancers, surgery may not be needed right away. Instead, your team may offer active surveillance. This means checking the cancer with regular neck ultrasounds, usually every 6 to 12 months at first, to see if it grows or spreads.

If it starts to grow, you can still have surgery. Many people like this option because it avoids or delays surgery and its side effects. Others feel calmer having the cancer removed. Both are reasonable choices.

Something you can do: If your cancer is very small, ask, "Am I a candidate for active surveillance?"

Surgery

Most people with thyroid cancer have surgery. It is done under general anesthesia through a cut in the front of the neck, often placed in a skin crease so the scar fades well.

Lobectomy. The surgeon removes one half (lobe) of the thyroid. This may be offered for small, lower-risk cancers. The other half may still make enough hormone, so you may not need hormone pills.

Total thyroidectomy. The surgeon removes the whole gland. This is used for larger cancers, cancer in both lobes, cancer that has spread, or when radioactive iodine may be needed.

Neck dissection. If cancer has spread to lymph nodes, or is likely to, the surgeon also removes lymph nodes from the centre or side of the neck.

Possible side effects. Most people recover well and go home within a day or two. Your team will watch for:

• Voice changes. The nerves to your voice box run beside the thyroid. A hoarse or weak voice after surgery is common and usually gets better over weeks to months. Rarely, it lasts.
• Low calcium. Four tiny glands behind the thyroid, called parathyroid glands, control your calcium. If they are bruised or removed, your calcium can drop. This can cause tingling around the mouth or in your fingers, or muscle cramps. It is usually short-term and treated with calcium pills. Call your team right away if you have these signs.
• Bleeding in the neck. This is rare but serious. Fast swelling or trouble breathing needs 9-1-1.

Radioactive iodine (RAI)

Thyroid cells take up iodine, and papillary and follicular cancer cells often do too. Radioactive iodine uses this to destroy thyroid cells left behind after surgery, including some cancer cells. It is usually taken as a capsule or drink. It is not used for medullary or anaplastic cancer.

Not everyone needs RAI. Your team decides based on your risk of the cancer coming back.

Getting ready. RAI works best when your TSH level is high. There are two ways to do this:

• Stopping your thyroid hormone pills for a few weeks. This can make you feel tired and low for a while.
• Getting two injections of man-made TSH before treatment, so you can keep taking your pills.

You will also follow a low-iodine diet for about one to two weeks before treatment. This usually means avoiding iodized salt, seafood, dairy products and egg yolks, among other foods. Your team will give you a list.

After treatment. Your body gives off some radiation for a few days. Your team will give you clear safety steps, such as sleeping alone, keeping a distance from children and anyone pregnant, and flushing the toilet twice. Side effects can include a sore or swollen neck, tender glands near your jaw, a dry mouth, a change in taste, and nausea. Sucking on sugar-free candy and drinking plenty of fluids can help. Most doctors advise waiting at least 6 months before trying to get pregnant.

Thyroid hormone pills

If your whole thyroid is removed, you will take a thyroid hormone pill, levothyroxine, every day for the rest of your life. It does the job your thyroid used to do.

For some people, the dose is set a little higher on purpose. This keeps TSH low, because TSH can encourage any remaining cancer cells to grow. Your team will check your blood and adjust the dose over time.

Something you can do: Take your pill the same way every day, usually on an empty stomach, and ask your pharmacist which foods, supplements or medicines to space apart from it.

Follow-up

After treatment, you will have regular check-ups. These often include thyroglobulin blood tests and neck ultrasounds. After a total thyroidectomy, thyroglobulin should be very low. A rise can be an early sign that the cancer is back. People with medullary cancer are followed with calcitonin and CEA blood tests.

Other treatments for some people

External beam radiation. A machine aims radiation at the neck or at spots where cancer has spread. It may be used when cancer can't be fully removed, doesn't take up iodine, or to ease symptoms.

Targeted therapy. These drugs block signals that help cancer cells grow. They are used for some advanced cancers that no longer respond to radioactive iodine, and for some medullary and anaplastic cancers. Examples include kinase inhibitors such as lenvatinib, drugs aimed at a gene change called RET, and drugs aimed at a gene change called BRAF. Your tumour may be tested for these gene changes. Side effects can include high blood pressure, diarrhea, tiredness and sore hands or feet.

Anaplastic thyroid cancer care. Because this type grows quickly, treatment starts fast. It may combine surgery, radiation, targeted drugs, chemotherapy or immunotherapy. Your team will also focus on keeping you comfortable and helping you breathe and swallow well.

Clinical trials. Studies test new treatments. Ask whether a trial might be right for you.

Questions to ask your care team

• What treatment do you recommend for me, and why?
• Am I a candidate for active surveillance or a lobectomy?
• What are the chances of voice changes or low calcium after my surgery?
• Will I need radioactive iodine? How do I prepare, and how do I keep my family safe?
• How will my thyroid hormone dose be checked and adjusted?
• What follow-up tests will I have, and how often?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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