Thyroid Cancer

Facts about thyroid cancer 

Q 1 what is thyroid cancer?

Thyroid cancer is a malignant tumor that starts in the cells of the thyroid.

The thyroid is a small gland in the front of the neck. It has a right and left lobe, one on each side of the trachea (windpipe). The lobes are joined by a thin piece of tissue called the isthmus.

Women are 2 to 3 times more likely to develop thyroid cancer than men.

Q 2 what are the causes of thyroid cancer?

  • Family history of thyroid cancer 
  • Radiation exposure in childhood – such as radiotherapy

Q 3 what are the types of thyroid cancer? 

  • Papillary carcinoma – the most common type, 
  • Follicular carcinoma 
  • Medullary thyroid carcinoma 
  • Anaplastic thyroid carcinoma – the rarest and most serious type, it usually affects people over the age of 60

Papillary and follicular carcinomas are sometimes known as differentiated thyroid cancers. They tend to be easier to treat than the other types.

Q 4 what are the symptoms of thyroid cancer?

  • A lump or swelling in the neck
  • Hoarseness or other voice changes
  • Difficulty in swallowing
  • Difficulty in breathing
  • A cough that doesn’t go away

A word of caution

All of these symptoms can also be caused by conditions that are not cancer. Kindly consult your doctor first. 

Q 6 How is thyroid cancer diagnosed? 

  • Medical history and physical examination
  • Thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), and thyroid antibodies are measured to check how well the thyroid is working. 
  • Blood tumor marker such as Calcitonin & Carcinoembryonic antigen (CEA)
  • Ultrasound of neck and thyroid 

It is the first investigation to be done for thyroid cancer 

  • If ultrasound suggests thyroid cancer then FNA biopsy is done for confirmation

In an FNA biopsy, the doctor uses a very thin, hollow needle attached to a syringe to withdraw (aspirate) a small amount of tissue or fluid from a suspicious area. The biopsy sample is then checked to see if there are cancer cells in it.

A word of caution 

  • There is a common myth that taking biopsy leads to the spread of cancer cells in the body. This is not true. Taking a biopsy does not lead to the spread of cancer cells in the body.
  • Biopsy confirms that it is cancer and not infection and also helps in knowing the type of cancer so that further treatment can be planned accordingly.  

If FNA biopsy confirms thyroid cancer then further test is done to look for spread of disease 

  • Computed tomography (CT) scan of the neck and/or chest
  • Laryngoscopy

A flexible tube with a camera and light at the tip is inserted up the nose and down the throat. 

Q 7 What is thyroid cancer staging? 

Staging is a measurement of how far cancer has spread.

After all the tests have been completed and the results are known, it should be possible to predict what stage the cancer is. The higher the stage, further cancer has spread

Staging for thyroid cancer depends on the age of the person when diagnosed.

Younger than 55 years of age

People younger than 55 years of age when diagnosed will have either stage 1 or stage 2 differentiated thyroid cancer.

  • Stage 1

The tumor may have grown into nearby tissues or cancer may have spread to nearby lymph nodes.

  • Stage 2

Cancer has spread to other parts of the body (called distant metastasis), such as to the lungs, liver or bone. This is also called metastatic thyroid cancer.

Age 55 and older

People 55 years of age and older when diagnosed will be given a stage from 1 to 4 for thyroid cancer.

  • Stage 1

The tumor is only in the thyroid and is no larger than 4 cm.

  • Stage 2

The tumor is larger than 4 cm and may have grown into nearby muscles in the neck or has spread to nearby lymph nodes

  • Stage 3

The tumor has grown into any of the following:

  • Soft tissue beneath the skin
  • Voicebox (larynx)
  • Windpipe (trachea)
  • Esophagus (food pipe)
  • A nerve to the larynx (called the recurrent laryngeal nerve)
  • Stage 4

The tumor has grown into 

  • The connective tissue in front of the spine (prevertebral fascia), 
  • Into blood vessels in the space between the lungs (mediastinum)
  • Has spread to other parts of the body (called distant metastasis), such as to the lungs, liver, or bone. This is also called metastatic thyroid cancer.

A word of caution 

Above staging is simplified version for your basic understanding. The reader is advised to follow the TNM staging system developed by American Joint Committee on Cancer (AJCC) in which 

  • T stands for the size and location of the primary tumor
  • N stands for nodes. It tells whether cancer has spread to the nearby lymph nodes
  • M stands for metastasis. It tells whether cancer has spread to distant parts of the body

Q 8 How thyroid cancer is treated?  

Thyroid cancer is curable if diagnosed at an early stage. Surgery is the only curative option. 

When deciding treatment options for a particular patient, the doctor will consider the following factors and will decide the individual treatment plan:

  • The size of the cancer
  • The stage of the cancer
  • The location of the cancer
  • Your overall health and ability to recover from surgery
  • Your personal preferences

Following are the general guidelines but treatment may vary from patient to patient:  


Surgery is the first treatment done for most thyroid cancers. Depending on the type, stage, risk group, and location of cancer, you may have one or more of the following types of surgery.

  • Lobectomy removes one side, or lobe, of the thyroid
  • Total thyroidectomy completely removes the thyroid. It is the most common type of surgery done for thyroid cancer
  • Neck dissection removes lymph nodes from the neck. Other issues around the thyroid may also be removed. Neck dissection is usually done when cancer has spread to lymph nodes in the neck 

Radioactive Iodine Therapy for Thyroid Cancer

  • The goal of radioactive iodine is to kill any remaining thyroid cells or thyroid cancer cells anywhere in your body. It helps keep cancer from coming back
  • Radioactive iodine is taken as a pill or liquid that you swallow. It’s absorbed into your blood and travels through the blood to collect in thyroid cells. This way it can destroy the thyroid gland and thyroid cancer cells with little effect on the rest of the body.

Hormonal therapy

  • Hormonal therapy with the drug levothyroxine (Synthroid, Eltroxin) is standard treatment after total thyroidectomy. It is used to replace the hormone thyroxine, which would normally be made by the thyroid. It is also used to slow down the growth of any remaining thyroid cancer cells and help keep cancer from coming back

Targeted therapy

Targeted therapy may be used to treat advanced thyroid cancer when radioactive iodine therapy hasn’t worked or has stopped working.