Thyroid Cancer

There are different types of thyroid cancer. Each type is determined by the cell type in which it begins. 

There are two main types of thyroid cells:

• Follicular cells are the most common cell type. They use iodine from the blood to produce thyroid hormone. The amount of thyroid hormone produced is controlled by the pituitary gland in the brain through a substance called thyroid-stimulating hormone (TSH).
• Parafollicular cells, also known as C cells, make the hormone calcitonin, which helps control how the body uses calcium.

There are three main types of thyroid cancer:

• Differentiated thyroid cancer
• Medullary thyroid carcinoma
• Anaplastic (undifferentiated) thyroid cancer

Thyroid lymphomas and sarcomas make up the set of much rarer forms of thyroid cancer.

Differentiated thyroid cancers

Differentiated thyroid cancers develop from follicular cells and are the most common thyroid cancer type. These include:

• Papillary cancers, also called papillary carcinomas or papillary adenocarcinomas, represent about 8 of 10 thyroid cancers. These slow-growing cancers usually affect only one lobe of the thyroid gland, but they often spread to the lymph nodes in the neck. Treatment is often successful for papillary cancers.
• Follicular cancers, also called follicular carcinoma or follicular adenocarcinoma, represent about 1 of 10 thyroid cancers and occur most often in countries where iodine is lacking in the diet. Generally, these cancers do not spread to lymph nodes, but can spread to other parts of the body. The follicular cancer prognosis is very good in most cases.
• Hṻrthle (Hurthle) cell cancer, also called oxyphil cell carcinoma, represents about 3% of thyroid cancers. It’s typically more difficult to detect and treat.

Medullary thyroid carcinoma (MTC)

Medullary thyroid carcinoma (MTC) starts in the parafollicular or C cells of the thyroid gland and makes up about 4% of thyroid cancers. This cancer type can be more difficult to find and treat, and may spread to lymph nodes or other areas of the body before it’s found in the thyroid. MTC cancer types include:

• Sporadic MTC is the most common type of MTC, making up about 8 of 10 MTC cancers. It mainly affects adults and occurs in only one thyroid lobe.
• Familial MTC is a cancer type that is inherited and often develops during childhood or early adulthood. This cancer usually occurs in both lobes of the thyroid gland.

Anaplastic (undifferentiated) thyroid cancer

Also called undifferentiated, anaplastic carcinoma is a rare form of thyroid cancer that makes up about 2% of all thyroid cancers. It may develop from an existing papillary or follicular cancer, tends to spread quickly, and is difficult to treat.

Thyroid lymphomas

This rare thyroid cancer type makes up less than 4% of all thyroid cancers.

Thyroid sarcomas

Like thyroid lymphomas, this rare thyroid cancer type makes up less than 4% of all thyroid cancers.

Researchers don’t know exactly what causes most types of thyroid cancer. Some cases are related to an inherited condition, or to gene mutations that occur during a person’s lifetime. Other thyroid cancers have no identifiable cause.

Thyroid cancer risk factors include:

Gender

Women have three times the risk of developing thyroid cancer as men.

Age

Women are most often diagnosed in their 40s or 50s. Men are generally diagnosed later, in their 60s or 70s.

Exposure to radiation

Radiation exposure from medical treatments or environmental sources, especially during childhood, can increase risk.

Iodine deficiency

In areas of the world where diets are low in iodine, thyroid risk is higher. This is not common in the United States.

Inherited disorders

Familial medullary thyroid cancer is usually caused by an inherited genetic mutation. Children of parents who carry the gene mutation have a 50% chance of inheriting it. Those who inherit it are very likely to develop medullary thyroid cancer. 

Family history of thyroid cancer

If your parent, sibling or child develops thyroid cancer, even if there is no inherited genetic disorder, your risk is increased.

Having any of these risk factors does not mean you will develop thyroid cancer. If you’re concerned about your risk, talk with your doctor.

If you have family members who have had thyroid cancer, especially if they have a known inherited gene disorder, consider talking with one of our genetic counselors.

Except for familial medullary thyroid cancer (MTC), most cases of thyroid cancer cannot be prevented, as most people who develop the disease do not have any known risk factors. There’s no general thyroid cancer screening test at this time.

Because familial MTC is an inherited disease, genetic testing can identify gene mutations before thyroid cancer develops or detect it early. If a genetic mutation is found, the thyroid may be removed to prevent cancer from developing. People who have their thyroid removed will need to take thyroid medication for the rest of their life.

Symptoms of thyroid cancer include:

• A lump or swelling in the neck
• Pain in the front of the neck that may extend to the ears
• Hoarseness or voice changes that does not improve
• Pain or difficulty swallowing
• Difficulty breathing (restricted airway)
• A constant cough not due to a cold

Many of these symptoms may be caused by other conditions that are not cancer. But let your doctor know if you’re experiencing anything unusual, so that you can identify and treat potential problems.

If you have symptoms of thyroid cancer, your doctor may recommend diagnostic testing. Scripps physicians use blood, lab and imaging tests to diagnose thyroid cancer.

Blood test

A blood sample is collected and checked for abnormal levels of hormones and other substances that can indicate a problem with the thyroid. Blood tests cannot confirm thyroid cancer, but they can let your doctor know if your thyroid is functioning as it should be. If not, other tests may be needed.

Biopsy

If other diagnostic tests suggest you have thyroid cancer, your doctor may order a biopsy to confirm the diagnosis. Generally, there are two ways to perform a thyroid biopsy:

• Fine-needle aspiration (FNA) biopsy uses a thin needle inserted through the skin to remove tissue samples from different parts of the thyroid. The samples are examined for cancer cells under a microscope.
• Surgical biopsy is when thyroid tissue is surgically removed for examination.

Ultrasound

Ultrasound is an imaging procedure that uses sound waves to create pictures of thyroid nodules. A wand-like instrument is moved over the neck to send sound waves into the tissue, and the images are then recorded and displayed for review. The image of the nodule can help the doctor decide if it’s likely to be cancer.

Radioiodine scan

Radioactive iodine is swallowed or injected into a vein, and absorbed by the thyroid gland. A camera tracks where the radioactivity is. Because medullary thyroid cancer does not absorb iodine, this test is used only for other thyroid cancer types.

Computed tomography (CT) scan

A CT scan is an imaging test that captures images of the body from different angles. The images are combined to create detailed cross-sectional views of organs, bones and blood vessels.

Magnetic resonance imaging (MRI)

MRI relies on a powerful magnet, radio waves and advanced digital technology to provide detailed images of organs, bone and soft tissue.

Positron emission tomography (PET) scan

A PET scan involves a type of radioactive sugar that existing cancer cells will quickly absorb so they can be identified under a special camera. It’s combined with a CT scan to give physicians the ability to view a picture of potentially cancerous areas through the PET while also seeing more detailed images from a CT scan.

Laryngoscopy

If thyroid cancer affects the vocal chords, the physician may perform a laryngoscopy to check your voice box (larynx) to determine if the vocal cords are functioning properly. 

Thyroid cancer staging describes how far cancer may have spread. Scripps oncologists use stages to develop a treatment plan and thyroid cancer prognosis.

Thyroid cancer stages differ depending on the type of cancer and the age of the patient:

• Papillary and follicular thyroid cancer in patients younger than 45 years
• Papillary and follicular thyroid cancer in patients 45 years and older
• Medullary thyroid cancer for all ages
• Anaplastic thyroid cancer, which is always considered stage IV thyroid cancer

Papillary and follicular thyroid cancer stages

Stage I: In patients younger than 45, stage I papillary and follicular thyroid cancer includes tumors of any size. Cancer may have spread to nearby tissues or lymph nodes, but not to other parts of the body. In patients age 45 or older, the tumor is 2 cm or less and is only in the thyroid.

Stage II: In patients younger than 45, stage II papillary and follicular thyroid cancer has spread to other areas, such as the lungs or bone, and may have spread to lymph nodes. In patients age 45 and older, the tumor is 2 to 4 cm and only in the thyroid.

Stage III: Stage III papillary and follicular thyroid cancer applies only to patients 45 years and older. The tumor is larger than 4 cm and only in the thyroid, or any size but has spread outside the thyroid and to lymph nodes in the neck.

Stage IV: Stage IV papillary and follicular thyroid cancer applies only to patients age 45 and older and has three substages:

• Stage IVA is when the tumor is any size and cancer has spread beyond the thyroid to tissues in the throat (including the larynx, trachea, esophagus or skin) and may have spread to lymph nodes in the neck and chest.
• Stage IVB is when the tumor is any size and cancer has spread to the neck near the spine, or around blood vessels in the upper neck or chest, and may have spread to lymph nodes.
• Stage IVC is when the tumor is any size and cancer has spread to other parts of the body, such as the lungs and bones, and may have spread to lymph nodes.

Medullary thyroid cancer stages

Stage 0: Stage 0 medullary cancer is found only through a special screening test. No tumor is found in the thyroid.

Stage I: Stage I medullary cancer is in the thyroid only, and the tumor is 2 cm or smaller.

Stage II: In stage II medullary cancer, the tumor is 2 to 4 cm and only in the thyroid, or any size and has spread to tissues just outside the thyroid, but not to lymph nodes.

Stage III: In stage III medullary cancer, the tumor is any size, has spread to lymph nodes near the trachea and may have spread to tissues just beyond the thyroid.

Stage IV: Stage IV medullary thyroid cancer is divided into three substages:

• Stage IVA is either of the following:
• The tumor is any size and cancer has spread outside the thyroid to tissues under the skin, trachea, esophagus or larynx, and may have spread to lymph nodes near the trachea or the larynx.
• The tumor is any size and cancer may have spread to tissues just outside the thyroid. Cancer has spread to lymph nodes on one or both sides of the neck or between the lungs.
• Stage IVB is when cancer has spread to the tissue in front of the spinal column, or has surrounded the carotid artery or the blood vessels in the area between the lungs. Cancer may have spread to lymph nodes.
• Stage IVC is when the tumor is any size and cancer has spread to distant parts of the body and may have spread to lymph nodes.

Anaplastic thyroid cancer stages

Anaplastic thyroid cancer always is considered stage IV.

A cancer diagnosis can turn your world upside down. It’s completely normal to feel anxious, scared, depressed or overwhelmed. Learning all you can about your diagnosis and your options can help you make informed, confident decisions about the next steps to take.

Questions and considerations

Here are some questions you may want to ask your doctor or health insurance provider regarding your diagnosis:

• Should I get a second opinion?
• How do I find a specialist?
• What is my cancer treatment plan?
• Will I have to miss work/school?
• What are the side effects of thyroid cancer treatment?
• How successful is my treatment likely to be?
• What costs will be covered by insurance?
• Which costs will I be responsible for?

Your Scripps cancer team is here to help you find the answers you need to take an active role in your care. In addition, there are a number of community resources that provide education, information and helpful resources — often at no cost.

Learn more about the many cancer patient resources available to you and your loved ones.

Your Scripps cancer care team includes professionals from every area of oncology, including endocrinologists, surgeons, radiation oncologists and nurses who specialize in cancer care.

In addition, our nurse navigators can help coordinate your care and ensure you have support and guidance throughout your treatment and recovery. Learn more about how Scripps puts you at the center of care.

Your Scripps cancer care team will customize your treatment plan based on several factors, including:

• The stage of your cancer
• Whether your cancer has spread
• Your age and overall health

Thyroid cancer surgery

Surgery is the most common treatment for thyroid cancer. Depending on the stage of the cancer and how far it may have spread, Scripps physicians may use several surgical procedures to treat thyroid cancer. These include:

• Lobectomy to remove only the tissue where cancer is found
• Near-total thyroidectomy to remove most of the thyroid gland
• Total thyroidectomy to remove the entire thyroid gland, which means the patient will need to take thyroid hormone replacement medication for the rest of their lives
• Lymphadenectomy to remove cancerous lymph nodes in the neck

Radiation therapy

Your thyroid cancer treatment plan also may include radiation therapy. Scripps radiation oncologists use advanced radiation therapy techniques that precisely target tumors while minimizing radiation exposure to nearby healthy tissues and organs.

• Radioactive iodine (RAI) therapy is a type of radiation treatment that uses radioactive iodine, usually given by mouth, to kill any remaining thyroid cancer cells that have not been surgically removed. Because only the thyroid absorbs iodine, radioactive iodine can kill cancer cells without harming healthy tissue.
• Intensity-modulated radiation therapy (IMRT) is an advanced form of radiation therapy. IMRT allows the radiation oncologist to specify the dose of radiation for the tumor while restricting the dose to surrounding healthy tissues.

Chemotherapy

Chemotherapy drugs may be used in combination with radiation therapy to treat anaplastic thyroid cancer. It’s usually not effective for other types of thyroid cancer.

Thyroid hormone therapy

Drugs that affect thyroid-stimulating hormone (TSH) may be part of a treatment plan to regulate thyroid hormone levels and prevent cancer from growing or returning.

Targeted therapy

Targeted therapy uses drugs that attack specific receptors on cancer cells. It is often used to treat medullary thyroid cancer, and it can also be used to treat papillary or follicular thyroid cancer that does not respond well to other treatments.

Some thyroid cancer treatment plans may involve clinical trials. Talk to your physician about whether a clinical trial is right for you.

For a list of clinical trials that are currently enrolling patients, see our current list of clinical trials.

Your Scripps cancer team will develop a customized treatment plan outlining the treatments and therapies we recommend for your care. Before you begin treatment, you and your physician will review your plan together and discuss any questions or concerns you may have.

Your thyroid cancer treatment plan generally includes:

• Family and medical history
• A summary of your cancer diagnosis and staging information
• Diagnostic testing completed (e.g., imaging, biopsy, lab tests)
• Plans for surgery, radiation, chemotherapy and/or other treatments
• Potential side effects of treatments
• Contact information for your cancer care team members

Along with helping you understand your course of treatment and encouraging discussion between you and your physician, your plan helps your team coordinate your care. You also can share your treatment plan with other providers who may be involved in your medical care.

Your thyroid cancer care team includes health and medical professionals from a wide range of specialties. Scripps will customize your team to ensure you have the expertise and support you need.

Your team may include:

• Endocrinologists
• Surgeons and surgical oncologists
• Radiation oncologists
• Medical oncologists
• Registered nurses
• Nurse navigators
• Dietitians
• Oncology social workers

Visit your cancer care team for more on our multidisciplinary approach to treatment.