Thyroid Cancer

What is the thyroid cancer?

Thyroid cancer starts in the cells of the thyroid.  The thyroid is a small, butterfly-shaped gland at the front of the neck that produces hormones for growth and metabolism.

An estimated 5,700 new cases of thyroid cancer will be diagnosed in Canadians in 2011. Women get it three times more often than men. The number of thyroid cancers is rising.  Between 1998 and 2007, thyroid cancer rose annually by 6.8% in men and 8.8% in women. More frequent use of diagnostic testing may be detecting earlier stage, asymptomatic thyroid cancers more frequently than in the past.

Thyroid cancer can be divided into four types.

Each type behaves differently and is treated differently:

• Papillary Carcinoma (well-differentiated thyroid cancer) is the most common type and since this type of thyroid cancer grows slowly, if found early enough, this type can often be cured.
• Follicular Thyroid Cancer (well-differentiated thyroid cancer) also progresses slowly, but because the cells divide faster, it can progress more quickly than papillary carcinoma.
• Medullary Thyroid Cancer grows faster than either papillary carcinoma or follicular thyroid cancer and usually appears in members of the same family--this type can be controlled if found early enough to prevent it spreading to the rest of the body.
• Anaplastic thyroid cancer (undifferentiated thyroid cancer) grows and spreads very quickly--it is the most common type of thyroid cancer found in people 60 years and older.

How do I know if I have thyroid cancer?

Thyroid cancer is unique since it can remain dormant for many years before symptoms appear.  If you have any of the following symptoms, you should see a doctor immediately. 

• a lump or swelling in the front of the neck
• swollen lymph nodes in the neck; this can often take the form of a large mass in the neck or as multiple swollen nodes in the thyroid
• hoarseness or other voice changes, including difficulty speaking in a normal voice
• trouble swallowing or breathing
• persistent pain in the throat or neck that does not go away
• diarrhea

Although you should see your doctor if you are having any of these symptoms, it does not mean you have cancer.  Tests for thyroid cancer include physical examinations (checking for swelling of lymph nodes, etc.) a blood test, ultrasounds, thyroid screening or a laryngoscopy (a visual examination in which the doctor looks deep into the throat).

What is my risk of getting it?

There is no one thing that causes a person to get thyroid cancer.  The following may contribute to thyroid cancer

• exposure to large amounts of radiation (such as the doses experienced in war, accidents or sometimes through extensive radiation therapy)
• family history of either thyroid cancer or goitres (enlarged thyroid glands)
• too little or too much iodine in a person’s diet.

Having any of the above risk factors does not guarantee that someone will develop this type of cancer. In fact, thyroid cancer most often develops without many of these risk factors. You should see your doctor if you develop symptoms that do not go away.

For more information:

• Prostate Cancer
• Lung Cancer
• Thyroid Cancer
• Bone Cancer
• Breast Cancer
• Cervical Cancer
• Childhood Cancer
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• Melanoma Skin Cancer
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• Government of Canada action on Cancer
• Latest Research on Cancer
• Facts and Figures on Cancer in Canada
• About the Government of Canada’s Cancer program
• What can I do if I have Cancer?