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Thyroid cancer is a rare type of cancer that develops in the thyroid, a butterfly-shaped gland located in the neck below the larynx (voice box). The thyroid is responsible for producing the hormones thyroxine (T4) and triiodothyronine (T3), which control important bodily functions such as heart rate, digestion, and body temperature. Thyroid cancers usually develop as an adenoma (a benign epithelial tumour), or a carcinoma (cancer arising from bone of soft tissue that lines organs).

Neuroendocrine cancers are a complex group of tumours that develop in the neuroendocrine system, which is responsible for regulating important bodily functions such as heart rate, blood pressure and metabolism. They most commonly develop in the gastro-intestinal tract, pancreas, and the lungs; however, they can develop anywhere in the body. These tumours develop from neuroendocrine cells, which are responsible for receiving signals from the nervous system and producing hormones and peptides (small proteins) in response. 

Thyroid cancer has a higher incidence in women, and is most commonly diagnosed in young adults and teenagers. However, anyone can develop this disease.

Types of thyroid cancer 

There are four main types of thyroid cancer, that are categorised by the types of cells they develop from.

Papillary thyroid cancer

Papillary thyroid cancer is the most common type of thyroid cancer and is often slow growing. It develops from follicular cells in the thyroid gland, which are responsible for the production and storage of T3 and T4 hormones. Follicular cells also produce thyroglobulin (Tg), which is a protein that assists in the synthesis of T3 and T4. Generally, this type of cancer is easily managed, has a lower metastasis rate and has a better prognosis compared to other types of thyroid cancer.

Follicular thyroid cancer

Follicular thyroid cancer is a rare type of thyroid cancer that also develops from follicular cells. Advanced follicular thyroid cancer may develop into a more rare and aggressive type of thyroid cancer called Hürthle cell carcinoma. It is the second most common type of thyroid cancer; however, it may appear more aggressive and may have a higher metastasis rate than papillary thyroid cancer.

Medullary thyroid cancer

Medullary thyroid cancer is a rare type of thyroid cancer that develops from parafollicular cells. These cells are responsible for the production of calcitonin, which is a hormone that controls the levels of calcium and potassium in the body. Medullary thyroid cancer is the third most common type of thyroid cancer, and usually occurs without a family history. Unfortunately, the outcomes of this type may not be as favourable as the more common types of thyroid cancer, may have higher metastasis rates, and the prognosis may not be as good. 

Anaplastic thyroid cancer

Anaplastic thyroid cancer is the rarest form of thyroid cancer. It is known to be highly aggressive and fast growing. It develops from follicular cells, and may develop from papillary or follicular thyroid cancers. Unfortunately, anaplastic thyroid cancer is the most lethal and may not have as good of a prognosis as the more common forms of thyroid cancer.


If thyroid cancer is detected, it will be staged and graded based on size, metastasis (whether the cancer has spread to other parts of the body) and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.

Cancers can be staged using the TNM staging system:

  • T (tumour) indicates the size and depth of the tumour.
  • N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
  • M (metastasis) indicates whether the cancer has spread to other parts of the body.

This system can also be used in combination with a numerical value, from stage 0-IV:

  • Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
  • Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and had not spread to lymph nodes. This stage is also known as early-stage cancer.
  • Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
  • Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also known as localised cancer.
  • Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.

Cancers can also be graded based on the rate of growth and how likely they are to spread:

  • Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
  • Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour. 
  • Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour. 

Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate treatment option for you. 

Treatment is dependent on several factors, including location, stage of disease and overall health. 

Treatment options for thyroid cancers may include:

  • Surgery, potentially including:
    • Turmour resection (removal of the tumour and a healthy margin of tissue surrounding it).
    • Partial thyroidectomy (removal of affected portion of the thyroid gland).
    • Total thyroidectomy (complete removal of the thyroid gland).
  • Radiation therapy.
  • Chemotherapy.
  • Immunotherapy.
  • Targeted therapy.
  • Clinical trials.
  • Palliative care.

For more information on treatment options, please refer to the Rare Cancers Australia Treatment Options page. 

Risk factors

The risk factors for thyroid cancer include:

  • Previous exposure to radiation.
  • Family history of thyroid cancers.
  • Mutation of the RET (rearranged during transfection) proto-oncogene.
  • Having other thyroid conditions, such as thyroid nodules, enlarged thyroid (goitre) or thyroid inflammation (thyroiditis).
  • Having multiple endocrine neoplasia type 2 (MEN 2).
  • Obesity.

Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.

Early symptoms

People with thyroid cancer may not present with any symptoms in the early stages of the disease. As the tumour progresses, some of the following symptoms may appear:

  • A painless lump in the neck.
  • Difficulty swallowing.
  • Difficulty breathing.
  • Changes in the voice, such as hoarseness.
  • Swollen lymph nodes in the neck.

Having an overactive or underactive thyroid is not usually a sign of thyroid cancer.

Not everyone with the symptoms above will have cancer but see your general practitioner (GP) if you are concerned.


If your doctor suspects you have thyroid cancer, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.

Physical examination

Your doctor will collect your overall medical history, as well as your current symptoms. Following this, they may examine your body to check for any abnormalities. More specifically, they will feel around your thyroid gland for signs of lumps or tenderness.

Imaging & blood tests

The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), x-ray, and/or positron emission tomography (PET scan), depending on where it is suspected the cancer is. The doctor may also look at other parts of the body  to check  for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions. A routine blood test includes a thyroid function test, which measures levels of thyroid hormones, such as T3, T4, thyroglobulin and thyroid-stimulating hormone (TSH).


Once the location(s) of the cancer has been identified, the doctor will perform a biopsy to remove a section of tissue using a needle. The tissue sample will then be analysed for cancer cells.

Prognosis (Certain factors affect the prognosis and treatment options)

While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on rate and depth of tumour growth, susceptibility to treatment, age, overall fitness, and medical history. Generally, early-stage thyroid cancers have good prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence. 


Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.