Diagnosis & staging
Thyroid cancer is rare.
The thyroid is located at the base of your throat, below your voice box (larynx) and above your collar bones.
The thyroid is shaped like a butterfly, with one lobe on each side of the windpipe (trachea). The lobes are connected by a narrow band of tissue (the isthmus). Each lobe is 4 - 6 cm (1.5 - 2.4 inches) long.
Image of thyroid
The thyroid makes the hormones thyroxine (T4) and triiodothyronine (T3).
Two parathyroid glands lie on the back of each lobe of the thyroid. These glands, along with C-cells in the thyroid, make calcitonin. Calcitonin controls calcium levels in your body.
Image of parathyroid
- Painless lump or swelling in your neck.
- Enlarged thyroid gland (goiter). Your shirt collar may feel tighter than normal.
- Advanced stage thyroid cancer symptoms (from cancer spreading to surrounding tissues):
- Difficulty breathing and swallowing.
- Hoarseness (raspy voice).
If you have any signs or symptoms that you are worried about, please talk to your family doctor or nurse practitioner.
Tests that may help diagnose thyroid cancer include:
- Physical exam: most thyroid cancers are found during routine check-ups by a doctor or nurse practitioner.
- Thyroid function blood tests: you should have these tests if you have an enlarged thyroid.
- Ultrasound scan: to see the tumour. You should have this test if you have an enlarged thyroid.
- Thyroid scan using a radioactive iodine tracer, to see the cancer.
- Biopsy: This is when a doctor takes a sample of your tissue. A specialty doctor (pathologist) then examines the tissue for cancer.
There are 4 main types of thyroid tumours, based on how the cancer cells look under a microscope.
- Most common type in Canada. Over 80% (80 out of 100) of thyroid cancers.
- Slow-growing. People have an excellent chance survival of diagnosed early.
- Usually found in only one of the lobes.
- Second most common type of thyroid cancer.
- Starts in the follicular cells of the thyroid. These cells make thyroid hormones.
- Slow-growing. People have an excellent chance survival of diagnosed early.
- Often treated with radioactive iodine since this tumour is most likely to take up radioactive iodine.
- Starts in C-cells of the thyroid. These cells make which the hormone calcitonin.
- Slow-growing. People have a good chance of survival if diagnosed early.
- Usually found in only one of the lobes.
- May spread to the lymph nodes or to other sites in the body.
- Least common type of thyroid cancer.
- More often in middle-aged and elderly people.
- Most aggressive type of thyroid cancer. It is fast-growing and spreads early.
- May be too advanced at the time of diagnosis to remove with surgery.
- Often treated with radiation therapy.
- Unfortunately, this type of cancer can rarely be cured.
Staging describes the cancer. Staging is based on how much cancer is in the body, where it was first diagnosed, if the cancer has spread and where it has spread to.
The stage of the cancer can help your health care team plan your treatment. It can also tell them how your cancer might respond to treatment and the chance that your cancer may come back (recur).
- Stage 1: Cancer is only in the thyroid.
- Stage 2: Cancer has spread to regional lymph nodes
- Stage 3: Cancer has spread to nearby tissue.
- Stage 4: Cancer has spread to distant parts of the body (metastasis)
Thyroid cancer is not given a grade.
Some thyroid cancers may be put into risk groups.
Talk to your health care team if you have questions about risk groups.
