What is thyroid cancer?

There are several different types of thyroid cancer, the most common is papillary thyroid cancer, which usually grows in one lobe of the thyroid gland (about 70-80% of all cases). Follicular thyroid cancer accounts for about 20% of thyroid cancers.

Less common thyroid cancers include medullary thyroid cancer, anaplastic thyroid cancer and thyroid sarcoma or lymphoma.

It is estimated that more than 4,000 people were diagnosed with thyroid cancer in 2023. The average age at diagnosis is 53 years old. 

Thyroid cancer is the ninth most commonly diagnosed cancer, and it is estimated that one in 79 people will be diagnosed by the time they are 85.


Thyroid cancer signs and symptoms

There are often no obvious signs of thyroid cancer, however you may have one or more of the following symptoms:

  • a lump in the neck or throat that may get bigger over time

  • difficulty breathing or swallowing

  • swollen lymph glands in the neck

  • a hoarse voice.

You should talk to your GP if you have any of these symptoms, as often thyroid cancer develops slowly, without obvious signs or symptoms.


Causes of thyroid cancer

Some factors that can increase your risk of thyroid cancer include:

  • a family history of the faulty gene called RET gene

  • having a thyroid condition such as an enlarged thyroid (goitre) or thyroid nodules

  • exposure to some forms of radiation, such as childhood radiation therapy treatment.


Diagnosis of thyroid cancer

Tests to diagnose thyroid cancer may include:

Blood tests

A blood test will check the levels of hormones (including T3 and T4) and the thyroid-stimulating hormone (TSH). A blood test can also help to identify non-cancerous thyroid conditions, such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid).

Ultrasound

A painless scan that takes about 20 minutes, an ultrasound produces pictures of internal organs. It can assist in determining if any lump in your neck is solid or fluid filled. It will also show whether any lymph nodes have been affected.

Biopsy

A doctor removes some of the thyroid tissue for examination under a microscope. The most common type of biopsy is called a fine needed aspiration, alternatively a doctor may do a hemi-thyroidectomy to remove tissue sample.

Radioisotope scan

This test is usually done if blood tests indicate an overactive thyroid (hyperthyroidism). A small amount of radioactive liquid (such as iodine) is injected into a vein in your arm prior to a gamma camera scan being done. The amount of radioactive liquid taken up by the thyroid gland is then measured.

Other scans

If cancer is detected in your thyroid, you may have other scans to see if the cancer has spread to other parts of your body, such as a CT, MRI or PET scan.

After a diagnosis of thyroid cancer  

After a diagnosis of thyroid cancer you may feel disbelief, uncertainty, fear and anxiety. There is no right or wrong way to feel and experiencing a range of emotions is normal. While the most common types of thyroid cancers have a very good long-term prognosis, you may still feel shocked and confused. It may help to talk to family and friends about how you are feeling.  

Ask your specialist to explain treatment options and any potential side effects and financial concerns. Take as much time as you can so that you can make well-informed decisions.  


Treatment for thyroid cancer

Most people with thyroid cancer receive a combination of treatments from surgery, thyroid hormone replacement therapy, radioactive iodine treatment, radiotherapy or chemotherapy. This will depend on the type and stage of thyroid cancer you have.

Palliative care

In some cases of thyroid cancer, your medical team may talk to you about palliative care. Palliative care aims to improve your quality of life by alleviating symptoms of cancer.

As well as slowing the spread of thyroid cancer, palliative treatment can relieve pain and help manage other symptoms. Treatment may include radiotherapy, chemotherapy or other drug therapies.

Surgery

The most common form of treatment is surgery, whereby a section or the whole thyroid gland is removed (partial or total thyroidectomy). As a preventative measure, the surgeon may also remove nearby lymph nodes (called a neck dissection).

T4 therapy

Thyroid hormone replacement therapy is given as a daily tablet to replace the thyroid hormones (thyroxine or T4) that your body can no longer produce after surgery. If you have had thyroid surgery you will need Thyroxine replacement for the rest of your life as it is very important to keep your body functioning at a normal healthy rate.

Radioactive iodine treatment

A form of internal radiation therapy, radioactive iodine treatment is typically taken in a gel tablet form. It destroys any cancer cells left behind after surgery. Talk to your doctor about the safety measures required for this type of treatment.

Radiation therapy (radiotherapy)

External radiation therapy (the use of high energy x-rays) may be given after surgery, particularly if the cancer has spread to lymph nodes in the neck, or for thyroid cancers that are less responsive to radioactive iodine treatment (such as medullary or anaplastic thyroid cancers).

Chemotherapy

Chemotherapy is sometimes used to treat thyroid cancer that is not responding to radioactive iodine treatment. It is usually given as a drug that is injected into a vein (intravenously). 

Treatment Team

Depending on your treatment, your treatment team may consist of a number of different health professionals, such as:
  • GP (General Practitioner) - looks after your general health and works with your specialists to coordinate treatment.
  • Endocrinologist- specialises in diagnosing and treating disorders of the endocrine (hormonal) system.
  • Endocrine surgeon- operates on the adrenal, thyroid and parathyroid glands as well as the pancreas.
  • Nuclear medicine specialist- coordinates the delivery of radioactive scans and treatment.
  • Cancer nurse - assists with treatment and provides information and support throughout your treatment.
  • Other allied health professionals - such as social workers, pharmacists, and counsellors.


Preventing thyroid cancer

There are no proven measures to prevent thyroid cancer.

However, if familial medullary thyroid cancer is detected in a family, the rest of the family can be tested for the mutated gene. If a family member has the mutated gene, they can elect to have preventative treatment, such as surgery to remove the thyroid.


Prognosis for thyroid cancer

It is not possible for a doctor to predict the exact course of a disease, as it will depend on each person's individual circumstances. However, your doctor may give you a prognosis, the likely outcome of the disease, based on the type of thyroid cancer you have, the test results, the rate of tumour growth, as well as your age, fitness and medical history.

The most common types of thyroid cancer have very good long-term prognosis, especially if the cancer is found early.