Thyroid Cancer

Thyroid cancer is a condition that begins in the tissue of the thyroid gland.

The thyroid gland is a small, butterfly shaped gland located in the neck. It produces important hormones that help with metabolism, regulating body temperature, and other bodily functions.

Thyroid cancer happens when the DNA in the cells of the thyroid mutates. Thyroid cancer can be caused by exposure to high levels of radiation, inherited disorders, or iodine deficiency.

Symptoms of thyroid cancer may include a painless lump in the neck, a hoarse voice, or difficulty with breathing or swallowing. Many thyroid cancers do not cause any symptoms.

Treatment for thyroid cancer includes surgery to remove all or part of the thyroid gland. Other treatments may be needed depending on the type and severity of the cancer.

Thyroid cancer is most common in people aged 25 to 65, so it can start in patients young if they have a family history of thyroid disease. Screening also increases the likelihood of catching thyroid cancer in its earlier, easier treated stages.

Thyroid cancer definition, symptoms and complications

What is thyroid cancer?

The thyroid is a gland that rests in the throat and produces hormones that assist in regulating different functions of the body. Some of these processes include the rate of metabolism (how fast you burn calories) and heartbeat.

Cancer beginning in the thyroid occurs when abnormal cells begin to grow out of control in the thyroid, often first detected as an unusual lump in the tissue. These lumps are called thyroid nodules. Not all thyroid nodules are cancerous, but if you notice a nodule it is important to see a health care provider. The tumors beginning in these organs can spread to lymph nodes, tissues, and other organs as the cancer progresses.

Learn more about thyroid nodules>>

Are there different types of thyroid cancer?

There are different types of thyroid cancer, including:

• Papillary and follicular: Thyroid cancer arising from the follicular cells of the thyroid are known as papillary or follicular thyroid cancer. These cancers are slow-growing and among the most curable of all cancers. 86% of people with thyroid cancer have papillary cancer.
• Medullary thyroid carcinoma: This form of thyroid carcinoma originates from the parafollicular cells, which produce the hormone calcitonin. They make up about 3% of all thyroid cancer cases and can be associated with a genetic cause, such as the inherited MEN2 syndrome.
• Anaplastic: This thyroid cancer (ATC) is a rare, but very serious and aggressive cancer. People with anaplastic cancer are usually older and are diagnosed on average between the ages of 65 to 75 years. This type of thyroid cancer is more common among people assigned female at birth, but the condition represents only 1-2% of all thyroid cancers.

What are the symptoms of thyroid cancer?

Thyroid cancer typically doesn’t cause any signs or symptoms early in the disease. Symptoms differ between patients, but those experiencing early stages of thyroid cancer may experience the following:

• Voice changes like hoarseness
• Difficulty swallowing
• Neck and throat pain
• A swelling in the neck or lump in the throat that can be felt

Like other cancers, thyroid cancer progresses in stages, during which symptoms may change or become more severe. The following stage systems are used to track the progress of thyroid cancer:

Stages for papillary and follicular thyroid cancers are stages I – IV, depending on extent of the disease and age of the patient at diagnosis.

For medullary thyroid cancer, stages are from I-IV, depending on size of the tumor and spread.

Anaplastic thyroid cancer is all considered Stage IV because of its aggressiveness, and because it has usually spread when it is discovered.

Are there complications to thyroid cancer?

Common complications resulting from thyroid cancer include difficulty or the inability to speak due to interactions with the region of the throat that produces speech (also known as the voice box). Other issues may be the spread of cancer to the lungs, bones or other tissues in the throat, known as metastatic cancer.

Thyroid cancer causes, risk factors and prevention

What causes or contributes to the development of thyroid cancer?

While there are no singular causes for any type of cancer, thyroid cancer is most often a result of environmental exposure to radiation or to a genetic condition that relates to the function of the thyroid.

Are there risk factors for developing thyroid cancer?

Anything that increases the risk of getting a disease is called a risk factor. Having a risk factor does not mean that someone will get a particular type of cancer; not having risk factors doesn’t mean that someone will not get a particular type of cancer.

Thyroid cancer occurs more often in people between the ages of 25 and 65 years. Risk factors for developing thyroid cancer include:

• Exposure to radiation
• Radiation treatments to the head and neck during infancy or childhood
• Having had goiter (enlarged thyroid) or a family history of thyroid disease
• Having the inherited disorder MEN (multiple endocrine neoplasia)
• Being assigned female at birth

Can thyroid cancer be prevented? How?

Most of the causes of thyroid cancer cannot be prevented. This is because they are inherited or developmental traits – such as family history of thyroid disease or multiple endocrine neoplasia – that cannot be changed within a person’s lifetime.

While some people may not ever be exposed to radiation, many of the exposures that do occur are not avoidable due to work-related activities, therapeutic radiation treatment, or environmental dangers. Awareness of risk (such as previous radiation therapy to the neck) can allow earlier diagnosis and treatment.

Thyroid cancer diagnosis and treatment

How is thyroid cancer diagnosed?

The following screenings, tests and procedures may be used to detect or diagnose thyroid cancer and determine the stage of its progress:

• History and physical exam: This overview exam looks at the patient’s past illnesses and treatments, symptoms, or health abnormalities. Pre-treatment evaluation of vocal cord function is also performed in the doctor’s office.
• Blood tests: Blood tests can help the physician tell if the thyroid is working normally. These include tests that detect thyroid-stimulating hormone (TSH), T3 and T4 (thyroid hormones), thyroglobulin, calcitonin and carcinoembryonic antigen (CEA).
• Biopsy: Tissue from the affected area is sampled to examine for cancer cells. This procedure can often be done with a fine aspiration needle in the physician’s office.
• Ultrasound: Using sound waves to create images as the waves bounce off the thyroid. This test can help determine if a thyroid nodule is solid or filled with fluid, check the number and size of thyroid nodules, and highlight nearby enlarged lymph nodes.
• CT or CAT scan: A series of detailed pictures of areas inside the body are taken from different angles, sometimes alongside an injection of dye to help visualize the organs or tissues more clearly.
• PET-CT scan: Radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body, visualizing where glucose is used in the body. Malignant tumor cells show up brighter in the image because they are more active and take up more glucose. During the same session, a CT scan is performed to accurately locate any abnormalities.
• Thyroid radioiodine scan: Radioactive iodine is swallowed and absorbed by thyroid tissue or cancer within this tissue. After absorption, a small camera is used to evaluate the iodine location. This test can also be used post-treatment to check for remaining cancer cells.
• MRI: Magnetic resonance imaging or MRI is a procedure that uses a magnet, radio waves, and a computer to take multiple detailed pictures of areas inside the body.

What options are available for thyroid cancer treatment? Are any more common or successful?

There are multiple factors of thyroid cancer that require medical attention, and several methods of treatment may be necessary to address all patient symptoms. Treatment also depends on cancer stage. Treatment methods include:

Surgery and other related procedures:

• Voice and vocal nerve preservation: The thyroid gland is wrapped around the voice box, airway and vocal cord nerves. These structures can be affected by cancer or its treatment. Endocrine surgeons at WashU Medicine and Siteman Cancer Center offer expertise in voice and vocal nerve preservation for thyroid cancer patients.
• Lobectomy: This treatment removes only the side of the thyroid where the cancer is found. Lymph nodes in the area may be taken out (biopsied) to see if they contain cancer.
• Near-total and total thyroidectomy: This surgery removes most of the thyroid except for a small part. Total thyroidectomy removes the entire thyroid.
• Lymph node dissection: When the cancer has spread from the thyroid, lymph node dissection removes lymph nodes in the neck that contain cancer.

After the thyroid gland is removed, many patients are treated by a radiation oncologist who uses radioactive iodine to kill any residual cancer cells. Patients then take synthetic thyroid hormone to replace the hormone formerly produced by their thyroid gland.

Radiation therapy

• Radioactive iodine: Patients are given a capsule that contains radioactive iodine. Because the thyroid takes up iodine, the radioactive iodine collects in any thyroid tissue remaining in the body and kills cancer cells.
• IMRT (Intensity modulated radiation therapy): This is an advanced form of external beam radiation therapy. Radiation specialists shape radiation doses to the exact three-dimensional shape of the tumor, so this technology is ideal for use on irregularly shaped tumors located in various places throughout the body. Specialists can also vary the amount of radiation in each beam targeted at the tumor or turn the radiation on and off during treatments. The precise control and flexibility of IMRT minimizes the amount of radiation going to surrounding healthy tissue and is often used for head and neck cancers.

Chemotherapy

• Targeted therapy: An FDA-approved tyrosine kinase inhibitor is commonly used to slow cancer growth for patients with unresectable recurrent disease or cancer that has traveled to other body areas.
• Hormone therapy: Oral hormones can stop cancer cells from growing. In treating thyroid cancer, hormones can be used to stop the body from making other hormones that might make cancer cells grow, or to supplement thyroid needs after removal of the thyroid gland.

There are also certain treatments that are standardized to different types of thyroid cancer. For information on type-specific treatments for medullary or anaplastic thyroid cancer, visit the Siteman Cancer Center website.

What is the prognosis for thyroid cancer? Is there a cure?

The prognosis and treatment options depend on the following:

• The stage of the cancer (whether it affects part of the thyroid, involves the whole thyroid, or has spread to other places in the body).
• Whether the tumor can be completely removed by surgery.
• The patient’s general health.

According to the American Cancer Society, the 5-year survival rate is almost 100% for localized papillary, follicular, and medullary thyroid cancers. For localized anaplastic thyroid cancer, the 5-year survival rate is 34%, because this type of cancer is much more aggressive. These numbers go down with regional and distant (metastatic) versions of thyroid cancer.