Thyroid cancer

Thyroid cancer is a type of cancer that affects the thyroid gland. There are a number of different types of thyroid cancer, but papillary thyroid cancer is the most common in younger people.

The thyroid gland

The thyroid gland is found at the base of your neck, just behind the hollow where your collar bones meet. The thyroid is separated into two halves, known as lobes. Usually, a cancer is found in just one lobe, though it can occur in both.

Who does it affect?
What are the symptoms?
How is it diagnosed?
How is it treated?
What are the treatment side-effects?
After treatment

Who does it affect?

Thyroid cancer is a relatively rare condition, especially in younger people. It is more common in women than men.

What are the symptoms?

The first sign of thyroid cancer is usually a painless lump on the neck, which gradually gets bigger. Occasionally this lump may interfere with your breathing or make it difficult to eat.

How is it diagnosed?

Thyroid cancer is usually diagnosed after an ultrasound scan and a needle biopsy. A needle biopsy involves the specialist inserting a thin needle into the lump and extracting a small amount of cells and fluid. These are inspected under a microscope to determine whether cancer is present.

How is it treated?

The treatment you receive for thyroid cancer will depend on its type, and how much it has grown or spread. The most common treatments for thyroid cancer are surgery and radiotherapy.


You may need surgery to remove the whole thyroid gland, or the part affected by the cancer.


The type of radiotherapy you will receive depends on the type of thyroid cancer you have.

  • Radioactive iodine treatment involves drinking or taking a capsule of iodine 131 (also known as I-131), which then circulates through your body in your bloodstream killing the cancer cells. You will need to stay in hospital for a few days following this treatment.
  • External radiotherapy involves using high-energy rays to target your cancer cells. You will usually have a course of treatments at the radiotherapy department of the hospital over four to six weeks.

Talk to your specialist about your individual treatment plan.

What are the treatment side effects?

You will normally need to remain in hospital for 1–2 days after thyroid surgery so the specialist can ensure you have made a good recovery. If the nerve supplying your voice box is damaged during the operation, you may have a hoarse voice for a while. This normally goes away on its own.

Radiotherapy can also make you feel tired and sick. You might experience skin irritation and hair loss in the area that is being treated by external radiotherapy.

After treatment

Hormone replacement

If your thyroid gland has been totally removed, you will need thyroid hormone replacement. These are necessary to keep your body functioning like it did before the cancer. You will need to take these thyroid-hormone replacement tablets every day.

Follow-up care

After your treatment is completed, you will still need to be seen regularly at an outpatients clinic for at least ten years, maybe longer. At this clinic, your specialist will be looking for any signs that your cancer has returned (this is known as a relapse). They will also check that your major organs, such as your heart and lungs, are still functioning correctly and haven’t been affected by your cancer treatment.

Long-term follow up

Once your risk of relapse has reduced, the focus of ongoing follow up changes to looking out for potential long term side effects of treatment. The risk of long term side effects depends on the type of cancer you had and the treatment you received. A personalised surveillance plan is usually created that outlines the specific long term follow up and ongoing investigations that you require. Many people are at low risk of future health problems but some will have significant ongoing health needs. Talk to your specialist about the potential long-term side effects of your treatment.

Updated March 2018, next review due 2021.