Thyroid cancer is a disease in which malignant (cancer) cells form in the tissues of the thyroid gland.
The thyroid is a gland at the base of the throat near the trachea (windpipe). It is shaped like a butterfly, with a right lobe and a left lobe. The isthmus, a thin piece of tissue, connects the two lobes. A healthy thyroid is a little larger than a quarter. It usually cannot be felt through the skin.
The thyroid uses iodine, a mineral found in some foods and in iodized salt, to help make several hormones. Thyroid hormones do the following:
Your doctor may find a lump (nodule) in your thyroid during a routine medical exam. A thyroid nodule is an abnormal growth of thyroid cells in the thyroid. Nodules may be solid or fluid-filled.
When a thyroid nodule is found, an ultrasound of the thyroid and a fine-needle aspiration biopsy are often done to check for signs of cancer. Blood tests to check thyroid hormone levels and for antithyroid antibodies in the blood may also be done to check for other types of thyroid disease.
Thyroid nodules usually don't cause symptoms or need treatment. Sometimes the thyroid nodules become large enough that it is hard to swallow or breathe and more tests and treatment are needed. Only a small number of thyroid nodules are diagnosed as cancer.
Thyroid cancer can be described as either:
Well-differentiated tumors (papillary thyroid cancer and follicular thyroid cancer) can be treated and can usually be cured.
Poorly differentiated and undifferentiated tumors (anaplastic thyroid cancer) are less common. These tumors grow and spread quickly and have a poorer chance of recovery. Patients with anaplastic thyroid cancer should have molecular testing for a mutation in the BRAF gene.
Medullary thyroid cancer is a neuroendocrine tumor that develops in C cells of the thyroid. The C cells make a hormone (calcitonin) that helps maintain a healthy level of calcium in the blood.
See the PDQ summary on Childhood Thyroid Cancer Treatment for information about childhood thyroid cancer.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk.
Risk factors for thyroid cancer include the following:
The genes in cells carry hereditary information from parent to child. A certain change in the RET gene that is passed from parent to child (inherited) may cause medullary thyroid cancer.
There is a genetic test that is used to check for the changed gene. The patient is tested first to see if he or she has the changed gene. If the patient has it, other family members may also be tested to find out if they are at increased risk for medullary thyroid cancer. Family members, including young children, who have the changed gene may have a thyroidectomy (surgery to remove the thyroid). This can decrease the chance of developing medullary thyroid cancer.
Thyroid cancer may not cause early signs or symptoms. It is sometimes found during a routine physical exam. Signs or symptoms may occur as the tumor gets bigger. Other conditions may cause the same signs or symptoms. Check with your doctor if you have any of the following:
The following tests and procedures may be used:
The prognosis and treatment options depend on the following:
Information courtesy of Minnesota Oncology
This information is not intended to replace the advice of a doctor. No Thyroid No Problem, Inc. disclaims any liability for the decisions you make based on this information. This information was sourced and adapted from Adapted from the National Cancer Institute's Physician Data Query (PDQ®) Cancer Information Summaries on www.cancer.gov.