Thyroid cancer

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Non-cancerous conditions of the thyroid

A non-cancerous, or benign, condition of the thyroid is a change to thyroid cells, but it is not cancer. Non-cancerous conditions do not spread (metastasize) to other parts of the body and are not usually life-threatening.

The following are non-cancerous conditions of the thyroid.


Hypothyroidism is when the thyroid does not make enough thyroid hormone to keep the body working properly. It can be caused by an autoimmune disease, radiation to the neck or thyroid, surgery to remove part or all of the thyroid or inflammation of the thyroid (called thyroiditis).

When you have hypothyroidism, some of your body functions start to slow down. This can cause fatigue, dry skin, hair loss, weight gain and feeling cold.

Doctors diagnose hypothyroidism by checking thyroid-stimulating hormone (TSH) and thyroxine (T4) levels in the blood.

Hypothyroidism is usually treated and controlled with thyroid hormone therapy using levothyroxine (Synthroid, Eltroxin). This drug replaces thyroxine, which is normally made by the thyroid. It may take some time to find the right dose so you don’t have symptoms of hypothyroidism. Doctors will adjust the dose of levothyroxine based on blood test results.


Hyperthyroidism is when the thyroid makes too much thyroid hormone. It can be caused by Graves’ disease (an autoimmune disease of the thyroid), thyroid nodules, thyroiditis, an enlarged thyroid (called goitre) or too much iodine in your diet.

Hyperthyroidism can cause nervousness, sleep problems, increased appetite, weight loss, feeling hot, frequent bowel movements and a rapid or irregular heartbeat.

Doctors will do blood tests to check thyroid function and radioactive iodine tests to diagnose hyperthyroidism.

Treatment options for hyperthyroidism include:

  • beta blocker drugs to treat symptoms until other treatments start working
  • antithyroid drugs to stop the thyroid from making too much thyroid hormone
  • radioactive iodine therapy
  • surgery to remove part or all of the thyroid

Benign thyroid nodules

Benign thyroid nodules are abnormal growths or lumps in the thyroid. They don’t usually cause any signs or symptoms. They are often found during a routine medical exam by a doctor. Sometimes they grow large enough for you to see or feel them. If the nodules are large, they may make it hard to swallow or breathe.

Most thyroid nodules are non-cancerous (benign), but a small number of them contain cancer cells. Doctors usually do a biopsy using fine needle aspiration to check thyroid nodules for cancer. They may also order other tests to see if a thyroid nodule is cancerous, including blood tests and ultrasound.

Treatment options for benign thyroid nodules include:


Thyroiditis is inflammation of the thyroid. There are several types of thyroiditis.

Hashimoto’s thyroiditis develops when antibodies attack the thyroid. It usually causes hypothyroidism, which often becomes permanent.

Post-partum thyroiditis may develop after a woman gives birth to a baby. It causes hyperthyroidism followed by hypothyroidism. Post-partum thyroiditis usually gets better on its own.

Subacute thyroiditis may develop from a virus. It tends to cause pain, hyperthyroidism and hypothyroidism.

Acute thyroiditis usually develops from bacteria. It makes you not feel well. It sometimes causes pain and hypothyroidism.

Drug-induced thyroiditis can be caused by drugs such as lithium and interferon. It causes hyperthyroidism or hypothyroidism. It usually continues for as long as the drug is taken.

Radiation thyroiditis may develop after treatment with radioactive iodine or external beam radiation therapy. It usually causes hypothyroidism, but sometimes it causes hyperthyroidism.

Diagnostic tests used to check for thyroiditis include:

  • blood tests to check how well the thyroid is working
  • tests to see if thyroid antibodies are in the blood
  • radioactive iodine tests

Thyroiditis is usually treated with drugs. The types of drugs used will depend on the type of thyroiditis and symptoms. These include:

  • thyroid hormone therapy
  • beta-blockers
  • anti-inflammatory drugs
  • corticosteroids
  • antibiotics or other drugs to treat the infection


Goitre is a larger than normal, or enlarged, thyroid. Goitre usually causes a swelling or lump in the neck. A large goitre may cause coughing, a hoarse voice or difficulty breathing.

In Canada, the most common cause of goitre is having many nodules in the thyroid. Goitre can also be caused by infections, certain medicines, pregnancy or not getting enough iodine from your diet.

Tests used to diagnose goitre include blood tests, ultrasound and radioactive iodine scan. If an imaging test shows that a goitre has one or more nodules, doctors may need to do fine needle aspiration to check the nodules for cancer.

Treatment options depend on what caused the goitre and include:

  • thyroid hormone therapy
  • iodine supplements
  • radioactive iodine therapy
  • surgery to remove the thyroid (called thyroidectomy)

autoimmune disease


active surveillance


