• Patients with thyroid cancers are treated by members of the BC Cancer Agency’s Head and Neck Tumour Group.
• For healthcare professional information on treating this cancer, please see our Cancer Management Guidelines.
• The thyroid gland is about the size of a quarter and is located low in the front of the neck, below the Adam's apple (voice box or larynx) and above the collar bones.
• The thyroid is butterfly-shaped with three sections. Two lobes, one on either side of the windpipe, are connected by a section called the "isthmus."
• This gland is part of the endocrine system and uses iodine from the blood to produce hormones that regulate the body’s metabolism (physical and chemical processes involving energy). The thyroid hormones are thyroxine (T4) and triiodothyronine (T3).
• Two parathyroid glands lie at the edge of each lobe of the thyroid. These glands, together with C-cells in the thyroid, control calcium levels in the body.

What causes it and who gets it?
Listed below are some of the known risk factors for this cancer. Not all of the risk factors below may cause this cancer, but they may be contributing factors.

• Thyroid cancer occurs most often in those between 25 and 65 years of age.
• Thyroid disorders are more common in females, but when a lump appears in a male, it has a greater chance of being malignant.
• People with chronic elevation of TSH (thyroid-stimulating hormone) have increased risk.
• People with an enlargement of the thyroid gland called a goiter or with a family history of goiter may have a risk of developing cancer of the thyroid if the cause of the goiter is not treated. This is a rare cause of thyroid cancer which is becoming increasingly less important.
• Some medullary carcinomas are hereditary.
• People who received radiation treatment to the neck area, usually to the thymus gland, when they were infants or children may develop thyroid cancer. This form of treatment was rare after 1950, and a thyroid cancer would have taken 15-30 years to develop.
• It is unlikely that thyroid cancer will be caused by the dose of X-rays used for diagnostic procedures.
• Thyroid cancer accounts for only 1% of invasive cancers.
• Statistics
• B.C.
• Canada

Can I help to prevent it?

• Include adequate amount of iodine in the diet. Diets in North America are generally not low in iodine.

Screening for this cancer

• Painless lump in the neck
• Enlarged thyroid gland (goiter) - or collar getting tight
• May present with lymph node metastasis
• Late symptoms - due to local growth and invasion of adjacent tissues may include:
• Difficulty breathing and swallowing
• Hoarseness
• Metastasis to other sites

Diagnosis
This is a list of some or all of the tests used to diagnose this type of cancer.

Types and stages
Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

• T describes the site and size of the main tumour (primary)
• N describes involvement of lymph nodes
• M relates to whether the cancer has spread (presence or absence of distant metastases)

Stages

Types
There are 4 main types of thyroid tumours:

Papillary carcinoma

• Most common form with 80% overall survival at 10 years.
• May remain localized for years with high rate of cure.
• May spread to lymph nodes but this does not worsen outlook.
• May develop distant metastases, but this is rare.

Follicular carcinoma

• Follicular cancers are most likely to spread by the bloodstream to lungs or bone
• Often treated with radioactive iodine since this tumour is most likely to capture radioactive iodine

Medullary carcinoma 

• Is more aggressive than papillary and follicular cancers. 
•  It may spread to the lymph glands or by the bloodstream.
• It often produces the hormone calcitonin, which is a useful marker.
• Usually only occurs on only one side of the thyroid.

Anaplastic carcinoma

• Occurs in middle aged and elderly people.
• Noted for fast growth and early spread.
• May be too advanced at the time of diagnosis to remove surgically.
• Often treated with radiation therapy alone.
• Most aggressive thyroid cancers, only a small proportion of patients are cured. 

Treatment
Cancer therapies can be highly individualized – your treatment may differ from what is described below.

         Surgery

• The treatment of choice for all localized thyroid cancers is surgery.
• Often, surgical removal (thyroidectomy) is all that is required.     
• The minimum operation is to remove the involved lobe. Removal of the isthmus and much of the other lobe may also be required.
• More extensive surgery of the neck may be needed depending on the type and size of the tumour or whether the cancer has spread to lymph nodes.
• Thyroid operations involve carefully preserving the parathyroid glands and the nerves that supply the larynx (voice box).

Radioactive Iodine Therapy

• ¹³¹Iodine ablation may be used after surgery to destroy any remaining thyroid tissue where cancer may recur or to treat disease that has already recurred or metastasized (spread).
• Only papillary and follicular cancers will take up iodine, and only 50% or less of these tumours are able to take up enough iodine to be therapeutic.
• Before iodine therapy, the patient must stop taking thyroxine (T4) for at least 4 weeks and triiodothyronine (T3) for at least 2 weeks so that treatment will work.
• Radioactive iodine is given as a drink, so a patient must to stay in hospital for a few days after a therapeutic dose to allow the radioactivity to fall to safe levels.
• Radioactive iodine is used in more than one way to treat metastatic thyroid cancer:
  First, a high dose of iodine is given to destroy normal thyroid tissue. The resulting state of hypothyroidism can promote the tumour to take up the iodine allowing it to be used as therapy.
• Then, to test whether the metastatic tumour has taken up the iodine, a full-body scan, the patient swallows a small amount of radioactive iodine. This outpatient test is called a radioactive iodine scan or radionuclide scan.
• Possible side effects of treatment include temporary bone marrow suppression, inflammation of salivary glands, nausea and vomiting.

Radiotherapy

• External beam radiation therapy is used following surgery and radioactive iodine therapy when there is a high risk of recurrence in the thyroid or neck. This may be because tissue has been left behind or because the tumour does not take up iodine.
• Radiation therapy may also be used to treat tumours that cannot be removed surgically.
• The course of treatment lasts between 4 and 7 weeks.
• Side effects may include temporary reddening of skin, sore throat and laryngitis.

Chemotherapy

• At present chemotherapy has only a limited role in the treatment of thyroid cancer.

Thyroxine Hormone Replacement

• After treatment it is essential to take thyroxine hormone pills to replace what the thyroid normally would produce. Slightly higher doses than are necessary for replacement alone appear to reduce the risk of cancer recurring.

Follow-up after treatment

• Guidelines for follow-up after treatment has ended have been developed by the BC Cancer Agency and are listed on our website.
• You will be returned to the care of your family doctor or specialist for regular follow-up.
• Follow-up testing is based on your type of cancer and your individual circumstances.
• The BCCA Survivorship Research Centre focusses on the issues that cancer survivors can face.

Coping with cancer

The Coping with Cancer section of our website is a joint project among different BC Cancer Agency departments and programs. This website section provides information and links that can help cancer patients with the physical, emotional, psychological and practical aspects of care. Each cancer experience is different, but in one way or another, many cancer patients share the same needs.

The effects of cancer and its treatment can present unique challenges: from practical concerns like money and housing, to emotional concerns like anxiety and grief. If you need support with the practical and emotional impacts of cancer, or in managing symptoms and side effects you can use the information in Coping with Cancer to connect to these resources.

Search our library catalogue

• The BC Cancer Agency Library has many resources about cancer, coping, talking to children, etc.  Please visit the Library in your Centre, call a librarian, or visit the Library online to see the many resources available.
• Automatically get a bibliography of books, videos and other items available through our library.

Recommended websites
The BC Cancer Agency has selected and evaluated these useful websites for your further information.

Thyroid Cancer
Websites for cancer survivors, and how to stay healthy after treatment.

Videos
View videos on cancer-related topics that the BC Cancer Agency produces.

How can I help with research at BC Cancer Agency?
BC Cancer Agency patients are very helpful when it comes to the fight against cancer. Here are a few ways that you can help:

• The BCCA is deeply involved in cancer research.  We operate various Research Programs, the BC Cancer Research Centre and Canada's Michael Smith Genome Sciences Centre.
• Clinical Trials – join our treatment-based research. Ask your oncologist if you qualify for a clinical trial. What are the pros and cons of joining a clinical trial?
• Tumour Tissue Repository – support our research by donating some of your cancer tissue.
• BC Cancer Foundation – support our research with a donation of money.

This information is awaiting Tumour Group approval.