Diagnosing thyroid cancer

Friday 1 January, 2016

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On this page:  Blood test | Ultrasound | Biopsy | Further scans | Staging | Prognosis | Which health professionals will I see? | Key points

If you have thyroid nodules, your doctor will suggest you have one or more of the following tests to work out whether the nodules could be cancer and whether you need treatment. It’s unlikely you will have all of the tests described in this section. Some of these tests can also show whether the cancer has spread to other parts of your body.

Blood test

Your doctor will do a blood test to check the levels of hormones (such as T3 and T4) and thyroid-stimulating hormone (TSH). A cancerous thyroid can continue to function normally, so a blood test may help rule out benign thyroid conditions, such as hypothyroidism or hyperthyroidism.

If your doctor suspects you have medullary thyroid cancer, the levels of calcitonin may also be checked. High calcitonin levels in the blood can be a sign of medullary thyroid cancer.


An ultrasound uses soundwaves to produce a picture of internal organs. If you have a lump in your thyroid, the ultrasound can help the doctor determine whether it is a fluid-filled cyst or a solid thyroid nodule.

The doctor will also check if the nodule has characteristics that suggest cancer. The scan can also show if the lymph nodes (small, bean-shaped structures) in your neck are affected.

The ultrasound scan is painless and takes about 15–20 minutes. A gel is spread over your neck, then a handheld device called a transducer is moved over the area. The device sends out soundwaves that echo when they meet something dense, like an organ or tumour. A computer changes these echoes into a picture.


If the doctor feels a nodule in your neck or sees one during an ultrasound, they may suggest a fine needle aspiration (FNA) biopsy.

During a FNA biopsy, a thin needle is inserted into the nodule and a very small tissue sample is taken from the nodule for examination under a microscope. You may be given local anaesthesia (pain relief) to numb the area. Sometimes an ultrasound is used to guide the needle to the right spot. If not enough cells are removed the first time, the process may be repeated.

If it’s not possible to determine the characteristics of the nodule with a FNA, the doctor may remove part of the thyroid (hemi-thyroidectomy) to help confirm the diagnosis. If thyroid cancer is found after a hemi-thyroidectomy, you may need further surgery to remove the rest of your thyroid and possibly some lymph nodes in the neck. This will depend on the size and type of cancer, and if you have nodules in the other thyroid lobe.

"My initial fine needle biopsy results were inconclusive, so I had half of my thyroid removed." - Jenny

Further scans

The following scans are sometimes used to see if the cancer has spread to other parts of your body. This process is called staging, and it will help your doctors to decide on the best treatment for you. See more details about the stages of thyroid cancer.

A CT scan and/or PET scan may also be repeated after surgery, such as a thyroidectomy, to check your health and how well the treatment is working.

CT scan

A CT (computerised tomography) scan uses x-ray beams to create a detailed three-dimensional picture of the inside of the body.

In most cases, the ultrasound gives enough information before thyroid surgery, but you may need a CT scan if your thyroid is very enlarged, if it is extending well into the chest, or if there is concern that cancer has spread to other areas in the neck.

Before the scan, dye may be injected into one of your veins to help make the pictures clearer. This may make you feel hot all over and also leave a strange taste in your mouth for a few minutes.

The dye used in a CT scan usually contains iodine. If you know you’re allergic to iodine or dyes, let the person performing the scan know in advance. You should also tell the doctor if you’re diabetic, have kidney disease or are pregnant.

The CT scanner is a large, doughnut-shaped machine. You will lie on a table that moves in and out of the scanner, and you may be asked to hold your breath for a few seconds during the scan. While it may take 30–60 minutes to prepare for the scan, especially if using a dye, the scan takes a few minutes. A CT scan can be noisy, but it is painless. Most people can go home as soon as the scan is over.

Some people feel afraid of confined spaces (claustrophobic). Let your health care team know if you are uncomfortable or claustrophobic during the scan. They may help you relax by allowing you to use headphones to listen to music, wear an eye mask or take a mild sedative.

PET scan

A PET (positron emission tomography) scan may be used after surgery to work out if the cancer has come back. It’s used only if the doctor thinks the cancer needs to be viewed in a different way.

Before the PET scan, you will be asked not to eat or drink for a period of time (fast). During the scan, you will be injected with a glucose solution containing a small amount of radioactive material. Cancer cells show up brighter on the scan because they take up more of the glucose solution than normal cells do.

You will be asked to sit quietly for 30–90 minutes while the glucose solution moves around your body, then you will be scanned to create pictures of radioactive areas in the body. While it may take several hours to prepare for the test, the scan itself takes only about 30 minutes.

Staging thyroid cancer

The tests described above help your doctors determine whether you have thyroid cancer.

Some tests also show if the cancer has spread to other parts of the body. This is called staging. Knowing the stage helps doctors recommend the best treatment for you. It is often not possible to completely stage the cancer until after surgery.

There are different ways of staging cancers; however, most cancers follow a general international staging system known as TNM (tumour, nodes, metastasis). Numbers or letters may be used after the T, N and M to provide more details. For example, a T1 tumour is smaller than a T2 tumour. The cancer may be grouped into further stages, based on your age and cancer type.

TNM system
  • T (Tumour) – indicates the size of the tumour – there are four main T stages for thyroid cancer. T1 is the smallest and T4 is the largest
  • N (Nodes) – indicates whether the cancer has spread to the lymph nodes. There are two main N groups – either the cancer has not spread to the lymph nodes (N0) or it has spread to the nodes (N1)
  • M (Metastasis) – indicates whether the cancer has spread to other parts of the body, such as the lungs or the bones (metastatic or secondary cancer)


Prognosis means the expected outcome of a disease. You may wish to discuss your prognosis and treatment options with your doctor, but it is not possible for any doctor to predict the exact course of the disease. Instead, your doctor can give you an idea of what may happen, based on statistics and common issues that affect people with the same type of thyroid cancer as you.

To work out your prognosis, your doctor will consider:

  • your test results
  • the type of thyroid cancer you have
  • the rate of tumour growth
  • how well you respond to treatment
  • other factors such as your age, fitness and medical history.

The most common types of thyroid cancer (papillary and follicular) have a very good long-term prognosis, especially if the cancer is found only in the thyroid or is confined to the nearby lymph nodes in the neck.

Even if it has spread (metastasised), the outcome can still be very good. See below for more information on survival rates.

"Sometimes I felt people were a little dismissive because thyroid cancer has a good outlook. They would say, ‘If you’re going to get cancer, that’s the best type to get.’ But I didn’t find this very helpful. Hearing the word ‘cancer’ made me feel gutted and afraid." – Jenny
Five-year survival rate

Most research studies monitor patients up to five years after treatment, so doctors commonly use five-year survival rates as a way to discuss prognosis.

This statistic estimates longer-term survival – it does not mean you will only survive for five years.

To determine the five-year survival rate, doctors collect information from people treated at least five years ago.

Improvements in treatments may mean that your outlook is now better.

Thyroid cancer has the highest five-year survival rate of all cancers (96%).

Women diagnosed with thyroid cancer generally have a slightly better prognosis than men (97% five-year survival rate). Younger people also tend to have a better prognosis than older people.

Which health professionals will I see?

Your GP will arrange the first tests to assess your symptoms. If these tests do not rule out cancer, you will usually be referred to an endocrinologist or endocrine surgeon, who will organise more tests and advise you about treatment options. This can be a worrying and tiring time, especially if you need several tests.

You will probably be cared for by a range of health professionals who specialise in different aspects of your treatment. This multidisciplinary team (MDT) will depend on the stage of the cancer. A list of people who make up this team is below.

Health professionals for early thyroid cancer
Health professional Role
endocrinologist specialises in diagnosing and treating disorders of the endocrine system
endocrine surgeon operates on the thyroid gland, parathyroid glands, adrenal glands and the endocrine pancreas
ENT surgeon
treats the ears, nose and throat, including lymph nodes in the neck, and checks the vocal cords before and after surgery
head and neck surgeon operates on cancer in the head and neck area
nuclear medicine specialist coordinates the delivery of radioactive iodine treatment and nuclear scans
nurses and nruse care coordinators
support patients and families throughout treatment and liaise with other staff
Additional health professionals you may see
Health professional Role
radiation oncologist prescribes and coordinates the course of radiotherapy
medical oncologist prescribes and coordinates the course of chemotherapy
counsellor, social worker
provide emotional support and link you to support services
dietitian recommends an eating plan to follow during treatment and recovery

Key points

  • Different types of tests are used to diagnose or check for thyroid cancer, but the diagnosis is usually made by a fine needle aspiration (FNA) biopsy.
  • During a FNA biopsy a small amount of tissue is removed from a nodule for examination under a microscope. In some cases, an ultrasound is used to guide the needle to the right spot.
  • You will have a blood test to check the levels of thyroid hormones in your blood.
  • Occasionally other tests, such as a CT scan or a PET scan, are used to investigate if the thyroid cancer has spread.
  • The doctor will tell you the size of the cancer and if it has spread (its stage). The TNM system is often used for staging. This stands for tumour, nodes, metastasis.
  • Sometimes, the information needed for accurate staging is available only after surgery.
  • Your doctor will talk to you about your prognosis, which is the expected outcome of a disease. Thyroid cancer has the highest five-year survival rate of all cancers (96%). Most thyroid cancers are treatable, and the cure rate is highest for papillary and follicular thyroid cancers.
  • You should see a doctor who specialises in treating disorders of the endocrine system. You may see other health professionals who work together as a multidisciplinary team (MDT) to treat you.
  • You will probably see more professionals if you have advanced thyroid cancer or need extra support.

Reviewed by: A/Prof Julie Miller, Specialist Endocrine Surgeon, The Royal Melbourne Hospital, Epworth Freemasons and Melbourne Private Hospitals, VIC; Polly Baldwin, Cancer Council Nurse, 13 11 20, Cancer Council SA; Dr Gabrielle Cehic, Nuclear Medicine Physician, Flinders Medical Centre, Lyell McEwin Hospital and The Queen Elizabeth Hospital, SA; Dr Kiernan Hughes, Endocrinologist, San Clinic Specialist Rooms & Chatswood Rooms, Northern Endocrine Pty Ltd, NSW; Dr Chris Pyke, A/Prof of Surgery, University of Queensland, Mater Hospital, Brisbane, QLD; and Jen Young, Consumer.

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