How is thyroid cancer diagnosed? 

It is important that your doctor establishes the diagnosis of thyroid cancer, assess the size of the cancer and whether it has spread to the lymph nodes in the neck or elsewhere in the body. 

To answer these questions your doctor will need to do the following things:

  • talk with you about your medical history. This includes signs you may have noticed, any health conditions, medications you are taking, and whether you smoke or drink alcohol

  • perform a physical examination by feeling and looking at your neck and throat

  • order diagnostic tests, which may include scans. 

Thyroid cancer is often found when someone has a scan of the neck area. However, there are lots of different exams or tests that can be used to confirm a diagnosis of thyroid cancer. Not everyone will need to have every test for thyroid cancer. Your doctor will recommend tests that are right for you.

Common tests include: 

Blood tests

Your doctor may suggest blood tests to check the levels of certain hormones and other thyroid cancer markers, if required (e.g. calcitonin and CEA [Carcinoembryonic Antigen]). 


ultrasound scan

Your doctor may suggest ultrasound to produce pictures of the thyroid and nearby lymph nodes, to look at any nodules (lumps) in the thyroid and also in the lymph nodes. 



Your doctor will use a very thin flexible tube with a tiny light and camera on it to check the function of vocal cords as nerves to your voice box, may be affected by thyroid cancer.



This involves removing a small piece (sample) from the cancer. The sample is then examined under a microscope to check for cancer cells. This is often the only sure way to tell if you have cancer.
Your doctor may recommend: 
  • Needle biopsy (Fine Needle Aspiration or FNA): This is used when there is a lump (enlarged lymph node) in your neck that could have cancer cells in it. During the procedure, your doctor will take some cells (a very small sample) from the lump using a needle. This is done by a radiologist or pathologist using an ultrasound to see that the needle is in the right spot. You may feel a bit uncomfortable during the biopsy.


thyroid (radio-isotype) scan 

Your doctor may suggest thyroid scan if blood tests indicate an overactive thyroid. This involves injecting a small amount of radioactive liquid (such as iodine) into your arm prior to a gamma camera scan. 


CT (Computed Tomography) scan

This uses X-rays to take pictures of the inside of the body. If the person has cancer, a CT scan can help the doctor see where it is, measure how big it is, and determine whether it has spread into nearby organs or other parts of your body.


MRI (Magnetic Resonance Imaging) scan

This uses magnetic fields to take pictures of the inside of the body. This helps the doctor see how far a cancer has grown into the tissue around it.


PET (Positron Emission Tomography) scan

This is a whole body scan that uses a radioactive form of sugar which can show if thyroid cancer has spread elsewhere in the body.