Thyroid Cancer

Cancer of the thyroid gland

By Sarah Leavitt, Medical Research EditorLast modified: March 21, 2011

Thyroid Cancer

In the United States, 37,000 new cases of thyroid cancer are diagnosed annually; in the UK this figure is around 3,000. The number of thyroid cancer cases diagnosed has doubled in the past 30 years. The number of women diagnosed is higher than men, with a 3 to 1 ratio.


What is thyroid cancer?

The thyroid gland is responsible for regulating hormone levels, temperature and blood pressure. The thyroid is an endocrine gland located in the neck. The thyroid also contributes to maintaining a stable weight and heart beat. Thyroid cancer is sometimes referred to as throat cancer.


There are four types of thryoid cancer: 


  • Papillary thyroid cancer - is the most commonly diagnosed thyroid cancer, accounting for 80% of all cases
  • Follicular thyroid cancer - 15% of diagnoses are for follicular thyroid cancer
  • Medullary thyroid cancer -can be hereditory and is responsible for 5-10% of thyroid cancer diagnoses
  • Anaplastic thyroid cancer - the rarest form of cancer of the thyroid gland. Less than 5% of cases

What causes thyroid cancer?

All forms of cancer are caused by a mutation of cells. When cells grow too rapidly the body is unable to cope with the number of cells and the immune system acts against the extra cells.


There is no clear cause for thyroid cancer. Exposure to radiation has been recognized as a trigger for thyroid cancer development.


Symptoms of thyroid cancer

Thyroid cancer is often symptom-less. Patients occasionally experience hoarseness and difficulty swallowing. For most patients, swollen lymph glands or a lump that can be felt though the skin are the first symptom of thyroid cancer.


Treatment for thyroid cancer

Thyroid cancer is curable in 97% of cases. The most common type of thyroid cancer, papillary thyroid cancer, rarely spreads outside the initial tumor. 


Treatment for thyroid cancer is a two-stage process*: The tumor is removed and then chemotherapy is administered. Papillary thyroid cancer rarely spreads outside the cancerous lump allowing doctors to remove only the infected nodule.


Medullary thyroid cancer often spreads to the lymph nodes. Oncologists must remove the complete thyroid gland and the lymph nodes in the neck.


Anaplastic thyroid cancer is a rapidly spreading form of thyroid cancer. It is often impossible to remove the tumor in its' entirety.  


Chemotherapy and thyroid cancer

One of the reasons 97% of thyroid cancers are curable is the thyroids unique susceptibility to chemotherapy. Healthy thyroid glands absorb iodine from the bloodstream to assist with hormone development. Cancerous thyroid cells absorb iodine in the same way. Using a radioactive iodine (often in pill form), the chemotherapy attacks the cells on the inside. 


Chemotherapy sickness is caused by healthy cells becoming contaminated with the poisonous radiation - because thyroid cells absorb the poison, no other cells are damaged. This means it is very rare for thyroid cancer patients to suffer any ill effects from chemotherapy. 


Ask an oncologist









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