A thyroid cancer is a form of cancer that affects the thyroid gland, which is located near the base of the neck and is a small, butterfly-shaped organ. Thyroid cancer is usually highly treatable and has a good prognosis. Thyroid hormones regulate metabolism, temperature, blood pressure, and heart rate. However, some types of thyroid cancer are more aggressive and harder to treat.
The exact cause of thyroid cancer is not known, but some factors may increase the risk of developing it. These include:
Exposure to radiation, especially during childhood or adolescence. This can come from medical treatments, such as radiation therapy for other cancers, or environmental sources, such as nuclear accidents or fallout.
Family history of thyroid cancer or certain genetic syndromes, such as multiple endocrine neoplasia (MEN) type 2 or familial medullary thyroid cancer (FMTC).
Diet low in iodine, which is essential for the normal function of the thyroid gland. Iodine deficiency is rare in developed countries, but more common in some parts of the world where iodized salt is not widely used.
Gender and age. Women and people assigned female at birth (AFAB) are about three times more likely to develop thyroid cancer than men and people assigned male at birth (AMAB). The disease is more common in people in their 40s and 50s, but can also occur in children and older adults.
Thyroid cancer may not cause any symptoms in its early stages, but as it grows, it may cause:
A lump or nodule in the neck that can be felt or seen
Changes in the voice, such as hoarseness or difficulty speaking
Difficulty swallowing or breathing
Pain or swelling in the neck or throat
Enlarged lymph nodes in the neck
To diagnose thyroid cancer, a health care provider will perform a physical examination and ask about the medical history and symptoms. The provider may also order some tests, such as:
Blood tests to measure the levels of thyroid hormones and other markers
Ultrasound to examine the size, shape, and texture of the thyroid gland and the presence of nodules or enlarged lymph nodes
Biopsy to remove a small sample of tissue from the thyroid gland or a nodule and examine it under a microscope for signs of cancer
Genetic tests to look for mutations in certain genes that are associated with thyroid cancer
Imaging tests, such as CT scan, MRI, or PET scan, to check for the spread of cancer to other parts of the body
Several treatment options are available for thyroid cancer, depending on its type, stage, and characteristics, as well as the patient's age and overall health.
Most types of thyroid cancer are treated with surgery to remove part or all of the thyroid gland and any affected lymph nodes. To maintain normal thyroid function, the patient may need to take thyroid hormone replacement pills for life after surgery.
A radioactive form of iodine is taken by the patient to kill any remaining thyroid tissue or cancer cells after surgery. It is absorbed by the thyroid cells and kills them. In order to avoid exposing others to radiation, the patient may need to stay away from children and pregnant women for a few days.
Radiation therapy can be used as a primary treatment for some types of thyroid cancer, or as an adjuvant treatment following surgery or radioactive iodine therapy for some types.
Some types of thyroid cancer, such as medullary or anaplastic thyroid cancer, respond well to targeted therapy using drugs that block specific molecules or pathways.
Chemotherapy to use drugs that kill cancer cells or stop them from dividing. This is rarely used for thyroid cancer, but may be an option for some advanced or resistant cases.
Some types of thyroid cancer can be slowed down by hormone therapy, which uses drugs that interfere with thyroid hormone production or action.
There is no sure way to prevent thyroid cancer, but some steps may help reduce the risk, such as:
Children and adolescents must avoid unnecessary radiation exposure. This includes limiting the use of medical tests or procedures that involve radiation, such as X-rays or CT scans, and following safety guidelines if working or living near a nuclear facility or a site of a nuclear accident.
Iodine is found in foods such as seafood, dairy products, eggs, and iodized salt, but too much iodine can be harmful, so it is not recommended to take iodine supplements without consulting your doctor.
Regular check-ups and screening tests can help detect thyroid cancer early, when it is easier to treat and cure. This is especially important for people with a family history or a genetic predisposition to thyroid cancer.