Thyroid cancer occurs in the cells of the thyroid — a butterfly-shaped gland located at the base of your neck, just below your Adam's apple. Your thyroid produces hormones that regulate your heart rate, blood pressure, body temperature and weight.
Although thyroid cancer isn't common in the United States, rates seem to be increasing. Doctors think this is because new technology is allowing them to find small thyroid cancers that may not have been found in the past.
Most cases of thyroid cancer can be cured with treatment.
Thyroid cancer typically doesn't cause any signs or symptoms early in the disease. As thyroid cancer grows, it may cause:
- A lump that can be felt through the skin on your neck
- Changes to your voice, including increasing hoarseness
- Difficulty swallowing
- Pain in your neck and throat
- Swollen lymph nodes in your neck
When to see a doctor
If you experience any these signs or symptoms, make an appointment with your doctor. Thyroid cancer isn't common, so your doctor may investigate other causes of your signs and symptoms first.
It's not clear what causes thyroid cancer. Thyroid cancer occurs when cells in your thyroid undergo genetic changes (mutations). The mutations allow the cells to grow and multiply rapidly. The cells also lose the ability to die, as normal cells would. The accumulating abnormal thyroid cells form a tumor. The abnormal cells can invade nearby tissue and can spread throughout the body.
Types of thyroid cancer
The type of thyroid cancer determines treatment and prognosis. Types of thyroid cancer include:
- Papillary thyroid cancer. The papillary type of thyroid cancer is the most common, making up about 80 percent of all thyroid cancer diagnoses.
- Follicular thyroid cancer. Follicular thyroid cancer also includes Hurthle cell cancer.
- Medullary thyroid cancer. Medullary thyroid cancer may be associated with inherited genetic syndromes that include tumors in other glands. However, most medullary thyroid cancers are sporadic, meaning they aren't associated with inherited genetic syndromes.
- Anaplastic thyroid cancer. The anaplastic type of thyroid cancer is very rare, aggressive and very difficult to treat.
- Thyroid lymphoma. Thyroid lymphoma begins in the immune system cells in the thyroid. Thyroid lymphoma is very rare.
Factors that may increase the risk of thyroid cancer include:
- Exposure to high levels of radiation. Examples of high levels of radiation include those that come from radiation treatment to the head and neck and from fallout from such sources as nuclear power plant accidents or weapons testing.
- Personal or family history of goiter. Goiter is a noncancerous enlargement of the thyroid.
- Certain inherited genetic syndromes. Genetic syndromes that increase the risk of thyroid cancer include familial medullary thyroid cancer, multiple endocrine neoplasia and familial adenomatous polyposis.
Thyroid cancer that comes back
Despite treatment, thyroid cancer can return, even if you've had your thyroid removed. This could happen if microscopic cancer cells spread beyond the thyroid before it's removed. Thyroid cancer recurrence can occur decades after thyroid cancer treatment.
Thyroid cancer may recur in:
- Lymph nodes in the neck
- Small pieces of thyroid tissue left behind during surgery
- Other areas of the body — most often the lungs or the bones
Thyroid cancer that recurs can be treated. Your doctor may recommend periodic blood tests or thyroid scans to check for signs of a thyroid cancer recurrence.
If you suspect thyroid cancer, you're likely to start by first seeing your family doctor or a general practitioner. If your doctor suspects you may have a thyroid problem, you may be referred to a doctor who specializes in diseases of the endocrine system (endocrinologist).
Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well prepared. Here's some information to help you get ready, and what to expect from your doctor.
What you can do
- Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
- Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications, vitamins or supplements that you're taking.
- Take a family member or friend along. Sometimes it can be difficult to recall all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Your time with your doctor is limited, so preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For thyroid cancer, some basic questions to ask your doctor include:
- What type of thyroid cancer do I have?
- What stage is my thyroid cancer?
- What treatments do you recommend?
- What are the benefits and risks of each treatment option?
- I have other health problems. How can I best manage them together?
- Will I be able to work and do my usual activities during thyroid cancer treatment?
- Should I seek a second opinion?
- Should I see a doctor who specializes in thyroid diseases?
- How quickly do I need to make a decision about thyroid cancer treatment? Can I take some time to consider my options?
- Are there any brochures or other printed material that I can take with me? What websites do you recommend?
If any additional questions occur to you during your visit, don't hesitate to ask.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over points you want to talk about in-depth. Your doctor may ask:
- When did you first begin experiencing symptoms?
- Are your symptoms occasional or continuous?
- How severe are your symptoms?
- Does anything seem to improve your symptoms?
- Does anything seem to make your symptoms worse?
- Have you ever been treated with radiation therapy?
- Have you ever been exposed to fallout from a nuclear accident?
- Does anyone else in your family have a history of goiter or thyroid or other endocrine cancers?
- Have you been diagnosed with any other medical conditions?
- What medications are you currently taking, including vitamins and supplements?
Tests and procedures used to diagnose thyroid cancer include:
- A physical exam to feel your neck for thyroid lumps and lymph node swelling
- Blood tests, including a test to measure the level of thyroid-stimulating hormone (TSH) in your body
- Imaging tests, such as ultrasound of the neck to help determine the nature of the nodule and to look for enlarged lymph nodes
- Ultrasound-guided needle biopsy to remove cells from your thyroid and examine them using a microscope to look for cancer
Your thyroid cancer treatment options depend on the type and stage of your thyroid cancer, your overall health and your preferences.
Most cases of thyroid cancer can be cured with treatment.
Most people with thyroid cancer undergo surgery to remove all or most of the thyroid. Operations used to treat thyroid cancer include:
- Removing all or most of the thyroid (thyroidectomy). Surgery to remove the entire thyroid is the most common treatment for thyroid cancer. In most cases, the surgeon leaves small rims of thyroid tissue around the parathyroid glands to reduce the risk of parathyroid damage. Sometimes surgeons refer to this as a near-total thyroidectomy.
- Removing lymph nodes in the neck. When removing your thyroid, the surgeon may also remove enlarged lymph nodes from your neck and test them for cancer cells.
Thyroid surgery is performed by making an incision in the skin at the base of your neck. Thyroid surgery carries a risk of bleeding and infection. Damage can also occur to your parathyroid glands during surgery, later leading to low calcium levels in your body. There's also a risk of accidental damage to the nerves connected to your vocal cords, which can cause vocal cord paralysis, hoarseness, soft voice or difficulty breathing.
Thyroid hormone therapy
After thyroid cancer surgery, you'll take the thyroid hormone medication levothyroxine (Levothroid, Synthroid, others) for life. This pill has two benefits: It supplies the missing hormone your thyroid would normally produce, and it suppresses the production of thyroid-stimulating hormone (TSH) from your pituitary gland. High TSH levels could conceivably stimulate any remaining cancer cells to grow.
You'll likely have blood tests to check your thyroid hormone levels every few months until your doctor finds the proper dosage for you.
Radioactive iodine treatment uses large doses of a form of iodine that's radioactive. Radioactive iodine treatment is often used after thyroidectomy to destroy any remaining healthy thyroid tissue, as well as microscopic areas of thyroid cancer that weren't removed during surgery. Radioactive iodine treatment may also be used to treat thyroid cancer that recurs after treatment or that spreads to other areas of the body.
Radioactive iodine treatment comes as a capsule or liquid that you swallow. The radioactive iodine is taken up primarily by thyroid cells and thyroid cancer cells, so there's a low risk of harming other cells in your body.
Side effects may include:
- Dry mouth
- Dry eyes
- Altered sense of taste or smell
- Pain where thyroid cancer cells have spread, such as the neck or chest
Most of the radioactive iodine leaves your body in your urine in the first few days after treatment. During that time you'll be given instructions for precautions you need to take to protect other people from the radiation. For instance, you may be asked to temporarily avoid close contact with other people, especially children and pregnant women.
External radiation therapy
Radiation therapy can also be given externally using a machine that aims high-energy beams at precise points on your body. Called external beam radiation therapy, this treatment is typically administered a few minutes at a time, five days a week, for about six weeks. During treatment, you lie still on a table while a machine moves around you. External radiation therapy is generally used to treat thyroid cancer that has spread to the bones.
Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. Chemotherapy is typically given as an infusion through a vein. The chemicals travel throughout your body, killing quickly growing cells, including cancer cells.
Chemotherapy is not commonly used in the treatment of thyroid cancer, but it may benefit some people who don't respond to other, more standard therapies.
Clinical trials are studies of new cancer treatments or new ways of using existing treatments. Enrolling in a clinical trial gives you the chance to try out the latest in cancer treatment options, but clinical trials can't guarantee a cure. Ask your doctor whether you might be eligible to enroll in a clinical trial. Together you can discuss the benefits and risks of a trial and decide whether participating in a clinical trial is right for you.
A diagnosis of thyroid cancer can be frightening. You might feel as if you aren't sure what to do next.
Everyone eventually finds his or her own way of coping with a cancer diagnosis. Until you find what works for you, consider trying to:
- Find out all you can about thyroid cancer. Write down the details of your thyroid cancer, such as the type, stage and treatment options. Ask your doctor where you can go for more information. Good sources of information to get you started include the National Cancer Institute and the American Cancer Society.
- Connect with other thyroid cancer survivors. You might find comfort in talking with people in your same situation. Ask your doctor about support groups in your area. Or connect with thyroid cancer survivors online through the American Cancer Society Cancer Survivors Network or the Thyroid Cancer Survivors' Association.
- Control what you can about your health. You can't control whether or not you develop thyroid cancer, but you can take steps to keep your body healthy during and after treatment. For instance, eat a healthy diet full of a variety of fruits and vegetables, get enough sleep each night so that you wake feeling rested, and try to incorporate physical activity into most days of your week.
Doctors aren't sure what causes most cases of thyroid cancer, so there's no way to prevent thyroid cancer in people who have an average risk of the disease.
Prevention for people with a high risk
People with an inherited gene mutation that increases the risk of medullary thyroid cancer may opt to have thyroid surgery to prevent cancer (prophylactic thyroidectomy). Discuss your options with a genetic counselor who can explain your risk of thyroid cancer and your treatment options.
Prevention for people near nuclear power plants
Fallout from an accident at a nuclear power plant could cause thyroid cancer in people living nearby. If you live within 10 miles of a nuclear power plant in the United States, you may be eligible to receive a medication (potassium iodide) that blocks the effects of radiation on the thyroid. If an emergency were to occur, you and your family could take the potassium iodide tablets to help prevent thyroid cancer. Contact your state or local emergency management department for more information.
- Expertise and experience. Mayo Clinic is internationally known for the treatment of thyroid problems, including cancer. Doctors at Mayo Clinic see more than 2,000 people with thyroid cancer each year.
- Teamwork. The integrated nature of Mayo Clinic's practice makes it easy for specialists to work together to develop the best treatment plan for you.
- Advanced technology. Mayo uses the latest technology, including state-of-the-art imaging, electronic monitoring of the laryngeal nerves and robotic thyroid surgery.
- Efficiency. In Mayo's efficient system, testing, diagnosis and the start of treatment can usually begin in days, not months.
Mayo Clinic in Rochester, Minn., is ranked among the Best Hospitals for cancer by U.S. News & World Report. Mayo Clinic in Jacksonville, Fla., and Mayo Clinic in Scottsdale, Ariz., are ranked high performing for cancer by U.S. News & World Report.
At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.
Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.
Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.
Why Choose Mayo Clinic
What Sets Mayo Clinic Apart
Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.
A team of specialists at Mayo Clinic in Arizona works together to identify the appropriate treatment approach for you. Thyroid tumors are treated by specialists in oncology, endocrinology, general surgery and ENT.
For appointments or more information, call the Central Appointment Office at 800-446-2279 (toll-free) 8 a.m. to 5 p.m. Mountain Standard Time, Monday through Friday or complete an online appointment request form.
- U.S. Patients
- International Patients
A team of specialists at Mayo Clinic in Florida works together to identify the appropriate treatment approach for you. Thyroid tumors are treated by specialists in endocrinology, general surgery, ENT, radiation oncology and oncology.
For appointments or more information, call the Central Appointment Office at 904-953-0853 8 a.m. to 5 p.m. Eastern time, Monday through Friday or complete an online appointment request form.
- U.S. Patients
- International Patients
At Mayo Clinic in Minnesota, thyroid cancer is managed by members of a thyroid core group within the Division of Endocrinology with a special interest in thyroid cancer. This multidisciplinary team includes specialists in oncology, endocrinology, general surgery, nuclear medicine and ENT.
For appointments or more information, call the Central Appointment Office at 507-538-3270 7 a.m. to 6 p.m. Central time, Monday through Friday or complete an online appointment request form.
- U.S. Patients
- International Patients
See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.
When detected early, cancer of the thyroid gland is highly treatable. Mayo Clinic doctors consider the following when diagnosing thyroid tumors.
- Physical exam. Your doctor will look for physical changes in your thyroid and ask about your risk factors, such as excessive exposure to radiation and a family history of thyroid tumors.
- Blood tests. Blood tests determine if the thyroid gland is functioning normally. In some people with thyroid cancer, blood tests may be useful in monitoring tumor extent and progression.
- Fine-needle aspiration. Fine-needle aspiration gathers cells to view under a microscope (biopsy) and is generally the first test to distinguish between benign and malignant tumors.
- Imaging tests. You may have one or more imaging tests, such as X-rays, magnetic resonance imaging (MRI), computerized tomography (CT) scans, positron emission tomography (PET) or ultrasound. These tests can help detect whether the cancer has spread. In tests that involve radiation, specialists carefully monitor doses to avoid the risk of radiation overexposure.
- Genetic testing. Thyroid cancers are most often not inherited, but some people with medullary thyroid cancer may have genetic changes that can be associated with other endocrine cancers. Most people with medullary thyroid cancer and their families should undergo genetic testing.
Mayo Clinic offers the latest treatment options for thyroid cancer. Treatment decisions are based on your needs. Two or more treatment therapies can be combined for some thyroid tumors.
- Surgery. Specialists at Mayo Clinic recommend near-total or total thyroid gland removal (thyroidectomy) when cancer cells are present. This ensures the best chance for survival and the lowest risk of recurring cancer. Your surgeon may also remove enlarged lymph nodes from your neck and test them for cancer cells.
- Robotic thyroid surgery. Robotic thyroidectomy may benefit certain individuals with small thyroid nodules who want to avoid a neck incision or who tend to form overgrown scar tissue (keloids). This procedure involves a high-resolution camera and robotic arms controlled by the surgeon using precise movements. An incision is made in the underarm area instead of the neck.
- Radioactive iodine treatment. Radioactive iodine treatment (radioiodine therapy) destroys thyroid tissue that may be left after thyroid surgery. This can limit the chance for cancer to recur. It can also be used to treat thyroid cancer that has spread beyond the thyroid gland.
- Thyroid hormone therapy. After a thyroidectomy, you will take a thyroid hormone replacement drug for the rest of your life.
- Alcohol ablation. Mayo Clinic doctors pioneered ultrasound-guided alcohol ablation treatment for recurring thyroid cancers. Alcohol ablation involves injecting small recurrent cancers with alcohol using imaging such as ultrasound to ensure precise placement. This treatment may kill recurrent tumor cells in regions that are difficult to reach surgically. Your doctor may recommend this treatment if you have recurrent thyroid cancer limited to small areas in your neck.
- Radiation therapy. Malignant thyroid tumors rarely require radiation therapy after surgery. It may be considered for treatment of inoperable tumors, for tumors that have spread and are causing symptoms, and when the risk of recurrence is high.
- Chemotherapy. Chemotherapy is typically reserved for anaplastic thyroid cancer or for certain cases in which the thyroid cancer has spread.
Clinical trials of new therapeutic approaches being further evaluated in carefully controlled studies may sometimes be appropriate for people with thyroid cancer. Researchers have compiled a database of information collected over several decades from people who have been treated for thyroid cancer at Mayo Clinic.
The thyroid research group at Mayo Clinic is actively working on issues such as:
- Genes involved with thyroid tumor development
- Risk factors associated with thyroid cancer
- Minimally invasive and robotic thyroid surgery
See a list of publications by Mayo Clinic doctors on thyroid cancer on PubMed, a service of the National Library of Medicine.
Apr. 02, 2011
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- Thyroid cancer: Detailed guide. American Cancer Society. http://www.cancer.org/Cancer/ThyroidCancer/DetailedGuide/index. Accessed Feb. 26, 2011.
- Prinz RA, et al. Thyroid cancer. In: Bope ET, et al. Conn's Current Therapy 2011. Philadelphia, Pa.: Saunders Elsevier; 2010. http://www.mdconsult.com/books/about.do?eid=4-u1.0-B978-1-4377-0986-5..C2009-0-38984-9--TOP&isbn=978-1-4377-0986-5&about=true&uniqId=236797353-5. Accessed Feb. 26, 2011.
- Consideration of potassium iodide in emergency planning. United States Nuclear Regulatory Commission. http://www.nrc.gov/about-nrc/emerg-preparedness/about-emerg-preparedness/potassium-iodide.html. Accessed Feb. 26, 2011.
- Nuclear power plant emergency preparedness. Federal Emergency Management Agency. http://www.nukepills.com/docs/FEMA_Nuclear_Power_Plant_Emergency.pdf. Accessed Feb. 26, 2011.
- Tuttle RM. Overview of the management of differentiated thyroid cancer. http://www.uptodate.com/home/index.html. Accessed Feb. 26, 2011.
- Nippoldt TB (expert opinion). Mayo Clinic, Rochester, Minn. March 3, 2011.