National Cancer Institute

What You Need 

To Know About TM

Thyroid

Cancer

U.S. DEPARTMENT OF 

HEALTH AND HUMAN SERVICES

National Institutes of Health

U.S. DEPARTMENT OF 

HEALTH AND HUMAN SERVICES

National Institutes of Health

National Cancer Institute

Contents

About This Booklet 1

The Thyroid 2

Cancer Cells 2

Types of Thyroid Cancer 5

Risk Factors 6

Symptoms 8

Diagnosis 9

Staging 11

Treatment 13

Second Opinion 23

Follow-up Care 24

Sources of Support 26

The Promise of Cancer Research 28

Dictionary 30

National Cancer Institute Information Resources 39

National Cancer Institute Publications 40
About This Booklet

This National Cancer Institute (NCI) booklet is

about cancer* that begins in the thyroid. Each year in

the United States, more than 25,000 women and 8,000

men learn they have thyroid cancer.

This booklet tells about diagnosis, staging,

treatment, and follow-up care. Learning about the

medical care for thyroid cancer can help you take an

active part in making choices about your own care.

This booklet has lists of questions that you may

want to ask your doctor. Many people find it helpful to

take a list of questions to a doctor visit. To help

remember what your doctor says, you can take notes or

ask whether you may use a tape recorder. You may also

want to have a family member or friend with you when

you talk with the doctor—to take part in the discussion,

to take notes, or just to listen.

For the latest information about thyroid

cancer, please visit our Web site at

http://www.cancer.gov/cancertopics/types/thyroid.

Or, contact our Cancer Information Service. We

can answer your questions about cancer. We can

send you NCI booklets and fact sheets. Call

1–800–4–CANCER (1–800–422–6237) or instant

message us through the LiveHelp service at

http://www.cancer.gov/help.

1

*Words in italics are in the Dictionary on page 30. The Dictionary

explains these terms. It also shows how to pronounce them.
The Thyroid

Your thyroid is a gland at the front of your neck

beneath your voice box (larynx). A healthy thyroid is a

little larger than a quarter. It usually cannot be felt

through the skin.

The thyroid has two parts (lobes). A thin piece of

tissue (the isthmus) separates the lobes.

The thyroid makes hormones:

• Thyroid hormone: Thyroid hormone is made by

thyroid follicular cells. It affects heart rate, blood

pressure, body temperature, and weight.

• Calcitonin: Calcitonin is made by C cells in the

thyroid. It plays a small role in keeping a healthy

level of calcium in the body.

Four or more tiny parathyroid glands are behind the

thyroid. They are on its surface. They make

parathyroid hormone, which plays a big role in helping

the body maintain a healthy level of calcium.

Cancer Cells

Cancer begins in cells, the building blocks that make

up tissues. Tissues make up the organs of the body.

Normal, healthy cells grow and divide to form new

cells as the body needs them. When normal cells grow

old or get damaged, they die, and new cells take their

place.

Sometimes, this orderly process goes wrong. New

cells form when the body does not need them, and old

or damaged cells do not die as they should. The buildup of extra cells often forms a mass of tissue called a

growth or tumor.

2
The pictures show the front and back of the thyroid.

Parathyroid

glands

Lobes

Isthmus

3

Lymph nodes

Isthmus

Thyroid

Larynx
Growths on the thyroid are often called nodules.

Most thyroid nodules (more than 90 percent) are

benign (not cancer). Benign nodules are not as harmful

as malignant nodules (cancer):

• Benign nodules

—are rarely a threat to life

—don’t invade the tissues around them

—don’t spread to other parts of the body

—usually don’t need to be removed

• Malignant nodules

—may sometimes be a threat to life

—can invade nearby tissues and organs

—can spread to other parts of the body

—often can be removed or destroyed, but

sometimes the cancer returns

Cancer cells can spread by breaking away from the

original tumor. They enter blood vessels or lymph

vessels, which branch into all the tissues of the body.

The cancer cells attach to other organs and grow to

form new tumors that may damage those organs. The

spread of cancer is called metastasis.

See the Staging section on page 11 for information

about thyroid cancer that has spread.

4
Types of Thyroid Cancer

There are several types of thyroid cancer:

• Papillary thyroid cancer: In the United States, this

type makes up about 80 percent of all thyroid

cancers. It begins in follicular cells and grows

slowly. If diagnosed early, most people with

papillary thyroid cancer can be cured.

• Follicular thyroid cancer: This type makes up

about 15 percent of all thyroid cancers. It begins in

follicular cells and grows slowly. If diagnosed early,

most people with follicular thyroid cancer can be

treated successfully.

• Medullary thyroid cancer: This type makes up

about 3 percent of all thyroid cancers. It begins in

the C cells of the thyroid. Cancer that starts in the

C cells can make abnormally high levels of

calcitonin. Medullary thyroid cancer tends to grow

slowly. It can be easier to control if it’s found and

treated before it spreads to other parts of the body.

• Anaplastic thyroid cancer: This type makes up

about 2 percent of all thyroid cancers. It begins in

the follicular cells of the thyroid. The cancer cells

tend to grow and spread very quickly. Anaplastic

thyroid cancer is very hard to control.

5
Risk Factors

Doctors often cannot explain why one person

develops thyroid cancer and another does not.

However, it is clear that no one can catch thyroid

cancer from another person.

Research has shown that people with certain risk

factors are more likely than others to develop thyroid

cancer. A risk factor is something that may increase the

chance of developing a disease.

Studies have found the following risk factors for

thyroid cancer:

• Radiation: People exposed to high levels of

radiation are much more likely than others to

develop papillary or follicular thyroid cancer. One

important source of radiation exposure is treatment

with x-rays. Between the 1920s and the 1950s,

doctors used high-dose x-rays to treat children who

had enlarged tonsils, acne, and other problems

affecting the head and neck. Later, scientists found

that some people who had received this kind of

treatment developed thyroid cancer.

(Routine diagnostic x-rays—such as dental x-rays or

chest x-rays—use very low doses of radiation. Their

benefits usually outweigh their risks. However,

repeated exposure could be harmful, so it’s a good

idea to talk with your dentist and doctor about the

need for each x-ray and to ask about the use of

shields to protect other parts of the body.)

Another source of radiation is radioactive fallout.

This includes fallout from atomic weapons testing

(such as the testing in the United States and

elsewhere in the world, mainly in the 1950s and

1960s), nuclear power plant accidents (such as the

Chornobyl [also called Chernobyl] accident in

6
1986), and releases from atomic weapons

production plants (such as the Hanford facility in

Washington state in the late 1940s). Such

radioactive fallout contains radioactive iodine

(I-131) and other radioactive elements. People who

were exposed to one or more sources of I-131,

especially if they were children at the time of their

exposure, may have an increased risk of thyroid

diseases. For example, children exposed to

radioactive iodine from the Chornobyl accident have

an increased risk of thyroid cancer.

For more information, you may want to read the

NCI fact sheet I-131 and Radioactive Fallout:

Questions and Answers. Page 40 tells how to get

NCI fact sheets.

• Family history of medullary thyroid cancer:

Medullary thyroid cancer sometimes runs in

families. A change in a gene called RET can be

passed from parent to child. Nearly everyone with

the changed RET gene develops medullary thyroid

cancer. The disease occurs alone as familial

medullary thyroid cancer or with other cancers as

multiple endocrine neoplasia (MEN) syndrome.

A blood test can detect the changed RET gene. If it’s

found in a person with medullary thyroid cancer, the

doctor may suggest that family members be tested.

For those who have the changed gene, the doctor

may recommend frequent lab tests or surgery to

remove the thyroid before cancer develops.

• Family history of goiters or colon growths: A

small number of people with a family history of

having goiters (swollen thyroids) with multiple

thyroid nodules are at risk for developing papillary

thyroid cancer. Also, a small number of people with

a family history of having multiple growths on the

inside of the colon or rectum (familial polyposis) are

at risk for developing papillary thyroid cancer.

7
• Personal history: People with a goiter or benign

thyroid nodules have an increased risk of thyroid

cancer.

• Being female: In the United States, women are

almost three times more likely than men to develop

thyroid cancer.

• Age over 45: Most people with thyroid cancer are

more than 45 years old. Most people with anaplastic

thyroid cancer are more than 60 years old.

• Iodine: Iodine is a substance found in shellfish and

iodized salt. Scientists are studying iodine as a

possible risk factor for thyroid cancer. Too little

iodine in the diet may increase the risk of follicular

thyroid cancer. However, other studies show that too

much iodine in the diet may increase the risk of

papillary thyroid cancer. More studies are needed to

know whether iodine is a risk factor.

Having one or more risk factors does not mean that

a person will get thyroid cancer. Most people who have

risk factors never develop cancer.

Symptoms

Early thyroid cancer often does not have symptoms.

But as the cancer grows, symptoms may include:

• A lump in the front of the neck

• Hoarseness or voice changes

• Swollen lymph nodes in the neck

• Trouble swallowing or breathing

• Pain in the throat or neck that does not go away

Most often, these symptoms are not due to cancer.

An infection, a benign goiter, or another health

problem is usually the cause of these symptoms.

Anyone with symptoms that do not go away in a

8
couple of weeks should see a doctor to be diagnosed

and treated as early as possible.

Diagnosis

If you have symptoms that suggest thyroid cancer,

your doctor will help you find out whether they are

from cancer or some other cause. Your doctor will ask

you about your personal and family medical history.

You may have one or more of the following tests:

• Physical exam: Your doctor feels your thyroid for

lumps (nodules). Your doctor also checks your neck

and nearby lymph nodes for growths or swelling.

• Blood tests: Your doctor may check for abnormal

levels of thyroid-stimulating hormone (TSH) in the

blood. Too much or too little TSH means the thyroid

is not working well. If your doctor thinks you may

have medullary thyroid cancer, you may be checked

for a high level of calcitonin and have other blood

tests.

• Ultrasound: An ultrasound device uses sound waves

that people cannot hear. The device aims sound

waves at the thyroid, and a computer creates a

picture of the waves that bounce off the thyroid. The

picture can show thyroid nodules that are too small

to be felt. The doctor uses the picture to learn the

size and shape of each nodule and whether the

nodules are solid or filled with fluid. Nodules that

are filled with fluid are usually not cancer. Nodules

that are solid may be cancer.

• Thyroid scan: Your doctor may order a scan of

your thyroid. You swallow a small amount of a

radioactive substance, and it travels through the

bloodstream. Thyroid cells that absorb the

radioactive substance can be seen on a scan.

Nodules that take up more of the substance than the

9
10

thyroid tissue around them are called “hot” nodules.

Hot nodules are usually not cancer. Nodules that take

up less substance than the thyroid tissue around them

are called “cold” nodules. Cold nodules may be

cancer.

• Biopsy: A biopsy is the only sure way to diagnose

thyroid cancer. A pathologist checks a sample of

tissue for cancer cells with a microscope.

Your doctor may take tissue for a biopsy in one of

two ways:

—Fine-needle aspiration: Most people have this

type of biopsy. Your doctor removes a sample of

tissue from a thyroid nodule with a thin needle.

An ultrasound device can help your doctor see

where to place the needle.
11

—Surgical biopsy: If a diagnosis cannot be made

from fine-needle aspiration, a surgeon removes

the whole nodule during an operation. If the

doctor suspects follicular thyroid cancer, surgical

biopsy may be needed for diagnosis.

Staging

To plan the best treatment, your doctor needs to

learn the extent (stage) of the disease. Staging is a

careful attempt to find out the size of the nodule,

whether the cancer has spread, and if so, to what parts

of the body.

You may want to ask your doctor these

questions before having a biopsy:

• Will I have to go to the hospital for the biopsy?

• How long will it take? 

• Will I be awake? Will it hurt?

• Are there any risks? What are the chances of

infection or bleeding after the biopsy?

• How long will it take me to recover?

• Will I have a scar on my neck?

• How soon will I know the results? Who will

explain the results to me?

• If I do have cancer, who will talk to me about

the next steps? When?
12

Thyroid cancer spreads most often to the lymph

nodes, lungs, and bones. When cancer spreads from its

original place to another part of the body, the new

tumor has the same kind of cancer cells and the same

name as the original cancer. For example, if thyroid

cancer spreads to the lungs, the cancer cells in the

lungs are actually thyroid cancer cells. The disease is

metastatic thyroid cancer, not lung cancer. For that

reason, it’s treated as thyroid cancer, not lung cancer.

Doctors call the new tumor “distant” or metastatic

disease.

Staging may involve one or more of these tests:

• Ultrasound: An ultrasound exam of your neck may

show whether cancer has spread to lymph nodes or

other tissues near your thyroid.

• CT scan: An x-ray machine linked to a computer

takes a series of detailed pictures of areas inside

your body. A CT scan may show whether cancer has

spread to lymph nodes, other areas in your neck, or

your chest.

• MRI: MRI uses a powerful magnet linked to a

computer. It makes detailed pictures of tissue. Your

doctor can view these pictures on a screen or print

them on film. MRI may show whether cancer has

spread to lymph nodes or other areas.

• Chest x-ray: X-rays of your chest may show

whether cancer has spread to the lungs.

• Whole body scan: You may have a whole body scan

to see if cancer has spread from the thyroid to other

parts of the body. You get a small amount of a

radioactive substance. The substance travels through

the bloodstream. Thyroid cancer cells in other organs

or the bones take up the substance. Thyroid cancer

that has spread may show up on a whole body scan.
13

Treatment

People with thyroid cancer have many treatment

options. Treatment usually begins within a few weeks

after the diagnosis, but you will have time to talk with

your doctor about treatment choices and get a second

opinion.

The choice of treatment depends on:

• the type of thyroid cancer (papillary, follicular,

medullary, or anaplastic)

• the size of the nodule

• your age

• whether the cancer has spread

You and your doctor can work together to develop a

treatment plan that meets your needs.

Your doctor may refer you to a specialist who has

experience treating thyroid cancer, or you may ask for

a referral. An endocrinologist is a doctor who

specializes in treating people who have hormone

disorders. You may see a thyroidologist, an

endocrinologist who specializes in treating diseases of

the thyroid.

You may have a team of specialists. Other

specialists who treat thyroid cancer include surgeons,

medical oncologists, and radiation oncologists. Your

health care team may also include an oncology nurse

and a registered dietitian.

Your doctor can describe your treatment choices and

the expected results. Thyroid cancer may be treated

with surgery, thyroid hormone treatment, radioactive

iodine therapy, external radiation therapy, or

chemotherapy. Most patients receive a combination of
14

treatments. For example, the standard treatment for

papillary cancer is surgery, thyroid hormone treatment,

and radioactive iodine therapy. Although external

radiation therapy and chemotherapy are not often used,

when they are, the treatments may be combined.

Surgery and external radiation therapy are local

therapies. They remove or destroy cancer in the

thyroid. When thyroid cancer has spread to other parts

of the body, local therapy may be used to control the

disease in those specific areas.

Thyroid hormone treatment, radioactive iodine

therapy, and chemotherapy are systemic therapies.

Systemic therapies enter the bloodstream and destroy or

control cancer throughout the body.

You may want to know about side effects and how

treatment may change your normal activities. Because

cancer treatments often damage healthy cells and

tissues, side effects are common. Side effects depend

mainly on the type and extent of the treatment. Side

effects may not be the same for each person, and they

may change from one treatment session to the next.

Before treatment starts, ask your health care team to

explain possible side effects and suggest ways to help

you manage them.

At any stage of disease, care is available to relieve

the side effects of treatment, to control pain and other

symptoms, and to help you cope with the feelings that

a diagnosis of cancer can bring. Information about

coping is available on NCI’s Web site at

http://www.cancer.gov/cancertopics/coping, and from

Information Specialists at 1–800–4–CANCER or

LiveHelp (http://www.cancer.gov/help).

You may want to talk to your doctor about taking

part in a clinical trial, a research study of new

treatment methods. See The Promise of Cancer

Research section on page 28.
15

You may want to ask your doctor these

questions before your treatment begins:

• What type of thyroid cancer do I have? May I

have a copy of the report from the pathologist?

• What is the stage of my disease? Has the

cancer spread from the thyroid? If so, to

where?

• What are my treatment choices? Which do you

recommend for me? Why?

• Will I have more than one kind of treatment?

• What are the expected benefits of each kind of

treatment?

• What are the risks and possible side effects of

each treatment? What can we do to control the

side effects?

• What can I do to prepare for treatment?

• Will I need to stay in the hospital? If so, for

how long?

• What is the treatment likely to cost? Will my

insurance cover the cost?

• How will treatment affect my normal

activities?

• What is my chance of a full recovery?

• Would a clinical trial be appropriate for me?

Can you help me find one?

• How often will I need checkups?
Surgery

Most people with thyroid cancer have surgery. The

surgeon removes all or part of the thyroid. The type of

surgery depends on the type and stage of thyroid

cancer, the size of the nodule, and your age.

• Total thyroidectomy: This surgery can be used for

all types of thyroid cancer. The surgeon removes all

of the thyroid through an incision in the neck. If the

surgeon is not able to remove all of the thyroid

tissue, it can be destroyed by radioactive iodine

therapy later.

Nearby lymph nodes also may be removed. If

cancer has invaded tissue within the neck, the

surgeon may remove nearby tissue. If cancer has

spread outside the neck, surgery, radioactive iodine

therapy, or external radiation therapy may be used to

treat those areas.

• Lobectomy: Some people with follicular or papillary

thyroid cancer may have only part of the thyroid

removed. The surgeon removes one lobe and the

isthmus. Some people who have a lobectomy later

have a second surgery to remove the rest of the

thyroid. Less often, the remaining thyroid tissue is

destroyed by radioactive iodine therapy.

The time it takes to heal after surgery is different for

each person. You may be uncomfortable for the first

few days. Medicine can help control your pain. Before

surgery, you should discuss the plan for pain relief with

your doctor or nurse. After surgery, your doctor can

adjust the plan if you need more pain relief.

Surgery for thyroid cancer removes the cells that

make thyroid hormone. After surgery, nearly all people

need to take pills to replace the natural thyroid

hormone. You will need thyroid hormone pills for the

rest of your life.

16
17

Thyroid Hormone Treatment

After surgery to remove part or all of the thyroid,

nearly everyone needs to take pills to replace the

natural thyroid hormone. However, thyroid hormone

pills are also used as part of the treatment for papillary

or follicular thyroid cancer. Thyroid hormone slows the

growth of thyroid cancer cells left in the body after

surgery.

If the surgeon removes the parathyroid glands, you

may need to take calcium and vitamin D pills for the

rest of your life.

In a few people, surgery may damage certain nerves

or muscles. If this happens, a person may have voice

problems or one shoulder may be lower than the other.

You may want to ask your doctor these

questions before having surgery:

• Which type of surgery do you suggest for me?

• Do I need any lymph nodes removed? Will the

parathyroid glands or other tissues be

removed? Why?

• What are the risks of surgery?

• How will I feel after surgery? If I have pain,

how will it be controlled?

• How long will I be in the hospital?

• What will my scar look like?

• Will I have any lasting side effects?

• Will I need to take thyroid hormone pills? If

so, how soon will I start taking them? Will I

need to take them for the rest of my life?

• When can I get back to my normal activities?
18

Thyroid hormone pills seldom cause side effects.

Your doctor gives you blood tests to make sure you’re

getting the right dose of thyroid hormone. Too much

thyroid hormone may cause you to lose weight and feel

hot and sweaty. It may also cause a fast heart rate, chest

pain, cramps, and diarrhea. Too little thyroid hormone

may cause you to gain weight, feel cold and tired, and

have dry skin and hair. If you have side effects, your

doctor can adjust your dose of thyroid hormone.

You may want to ask your doctor these

questions before taking thyroid hormone:

• Why do I need this treatment?

• What will it do?

• How long will I be on this treatment?

Radioactive Iodine Therapy

Radioactive iodine (I-131) therapy is a treatment for

papillary or follicular thyroid cancer. It kills thyroid

cancer cells and normal thyroid cells that remain in the

body after surgery.

People with medullary thyroid cancer or anaplastic

thyroid cancer usually do not receive I-131 therapy.

These types of thyroid cancer rarely respond to I-131

therapy.

Even people who are allergic to iodine can take

I-131 therapy safely. The therapy is given as a liquid or

capsule that you swallow. I-131 goes into the

bloodstream and travels to thyroid cancer cells

throughout the body. When thyroid cancer cells take in

enough I-131, they die.

Many people get I-131 therapy in a clinic or in the

outpatient area of a hospital and can go home
19

afterward. Some people have to stay in the hospital for

one day or longer. Ask your health care team to explain

how to protect family members and coworkers from

being exposed to the radiation.

Most radiation from I-131 is gone in about one

week. Within three weeks, only traces of I-131 remain

in the body.

During treatment, you can help protect your bladder

and other healthy tissues by drinking a lot of fluids.

Drinking fluids helps I-131 pass out of the body faster.

Some people have mild nausea the first day of I-131

therapy. A few people have swelling and pain in the

neck where thyroid cells remain. If thyroid cancer cells

have spread outside the neck, those areas may be

painful too.

You may have a dry mouth or lose your sense of

taste or smell for a short time after I-131 therapy.

Chewing sugar-free gum or sucking on sugar-free hard

candy may help.

A rare side effect in men who receive a high dose of

I-131 is loss of fertility. In women, I-131 may not

cause loss of fertility, but some doctors advise women

to avoid getting pregnant for one year after a high dose

of I-131.

Researchers have reported that a very small number

of patients may develop a second cancer years after

treatment with a high dose of I-131. See the Follow-up

Care section on page 24 for information about

checkups after treatment.

A high dose of I-131 also kills normal thyroid cells,

which make thyroid hormone. After radioactive iodine

therapy, you need to take thyroid hormone pills to

replace the natural hormone.

You may wish to read the NCI fact sheet Radiation

Therapy for Cancer: Questions and Answers. Page 40

tells how to get NCI fact sheets.
20

External Radiation Therapy

External radiation therapy (also called radiotherapy)

is a treatment for any type of thyroid cancer that can’t

be treated with surgery or I-131 therapy. It’s also used

for cancer that returns after treatment or to treat bone

pain from cancer that has spread.

External radiation therapy uses high-energy rays to

kill cancer cells. A large machine directs radiation at

the neck or other tissues where cancer has spread.

Most patients go to the hospital or clinic for their

treatment, usually 5 days a week for several weeks.

Each treatment takes only a few minutes.

You may want to ask your doctor these

questions before having radioactive iodine

therapy:

• Why do I need this treatment?

• What will it do?

• How do I prepare for this treatment? Do I need

to avoid foods and medicines that have iodine

in them? For how long?

• Will I need to stay in the hospital for this

treatment? If so, for how long?

• How do I protect my family members and

others from the radiation? For how many days?

• Will the I-131 therapy cause side effects? What

can I do about them?

• What is the chance that I will be given I-131

therapy again in the future?
21

The side effects depend mainly on how much

radiation is given and which part of your body is

treated. Radiation to the neck may cause a dry, sore

mouth and throat, hoarseness, or trouble swallowing.

Your skin in the treated area may become red, dry, and

tender.

You are likely to become tired during radiation

therapy, especially in the later weeks of treatment.

Resting is important, but doctors usually advise

patients to try to stay as active as they can.

Although the side effects of radiation therapy can be

distressing, your doctor can usually treat or control

them. The side effects usually go away after treatment

ends.

You may wish to read the NCI booklet Radiation

Therapy and You. Page 40 tells how to get NCI

booklets.

You may want to ask your doctor these

questions about external radiation therapy:

• Why do I need this treatment?

• When will the treatments begin? How often

will I have them? When will they end?

• How will I feel during treatment?

• How will we know if the radiation treatment is

working?

• What can I do to take care of myself during

treatment?

• Can I continue my normal activities?

• Are there any lasting side effects?
22

Chemotherapy

Chemotherapy is a treatment for anaplastic thyroid

cancer. It’s sometimes used to relieve symptoms of

medullary thyroid cancer or other thyroid cancers.

Chemotherapy uses drugs to kill cancer cells. The

drugs are usually given by injection into a vein. They

enter the bloodstream and can affect cancer cells all

over the body.

You may have treatment in a clinic, at the doctor’s

office, or at home. Some people may need to stay in

the hospital during treatment.

The side effects of chemotherapy depend mainly on

which drugs and how much are given. The drugs can

harm normal cells that divide rapidly, such as the cells

in the mouth. The most common side effects include

nausea, vomiting, mouth sores, loss of appetite, and

hair loss. Your health care team can suggest ways to

control many of these side effects. Most side effects go

away after treatment ends.

You may wish to read the NCI booklet

Chemotherapy and You. Page 40 tells how to get NCI

booklets.

You may want to ask your doctor these

questions about chemotherapy:

• Why do I need this treatment?

• What will it do?

• Will I have side effects? What can I do about

them?

• How long will I be on this treatment?
23

Second Opinion

Before starting treatment, you might want a second

opinion about your diagnosis and treatment plan. Many

insurance companies cover a second opinion if you or

your doctor requests it. A second opinion can make

you feel more confident about the diagnosis and

treatment choices.

It may take some time and effort to gather your

medical records and see another doctor. In most cases,

it’s not a problem to take several weeks to get a second

opinion. The delay in starting treatment usually will

not make treatment less effective. To make sure, you

should discuss any delay with your doctor.
24

There are many ways to find a doctor for a second

opinion. You can ask your doctor, a local or state

medical society, a nearby hospital, or a medical school

for names of specialists. Other sources can be found in

NCI’s fact sheet How To Find a Doctor or Treatment

Facility If You Have Cancer. Page 40 tells how to get

NCI fact sheets.

Follow-up Care

You need regular checkups after treatment for

thyroid cancer. Even when there are no longer any

signs of cancer, the disease sometimes returns because

cancer cells remained somewhere in the body after

treatment.

Your doctor monitors your recovery and checks for

return of the cancer with blood tests and imaging tests.

If thyroid cancer returns, it is most commonly found in

the neck, lungs, or bones.

Also, checkups help detect health problems that can

result from cancer treatment. People treated with

radioactive iodine therapy or external radiation therapy

have an increased chance of developing other cancers

later on. If you have any health problems between

checkups, you should contact your doctor.

People treated for papillary or follicular thyroid

cancer have blood tests to check the levels of TSH and

thyroglobulin. Thyroid hormone is normally stored in

the thyroid as thyroglobulin. If the whole thyroid has

been removed, there should be very little or no

thyroglobulin in the blood. A high level of

thyroglobulin may mean that thyroid cancer has
25

returned. Your doctor helps you get ready for a

thyroglobulin test in one of two ways:

• You stop taking your thyroid hormone pills for a

short time: About six weeks before the

thyroglobulin test, your doctor may change the type

of thyroid hormone pill you take. About two weeks

before the test, you stop taking any type of thyroid

hormone pill. This can cause uncomfortable side

effects. You may gain weight and feel very tired. It

may be helpful to talk with your doctor or nurse

about ways to cope with such problems. After the

thyroglobulin test, you can take your usual thyroid

hormone pill again.

• You get a shot of TSH: Your doctor may give you a

shot of TSH. If any cancer cells remain in the body

after treatment, TSH causes them to release

thyroglobulin. The lab checks the level of

thyroglobulin in the blood. People who get this shot

don’t have to stop taking their thyroid hormone pill.

People treated for medullary thyroid cancer have

blood tests to check the level of calcitonin and other

substances.

In addition to blood tests, checkups may include one

or more of the following imaging tests:

• Ultrasound: An ultrasound exam of the neck may

show whether cancer has returned there.

• Whole body scan: To get ready for the whole body

scan, you either stop taking your thyroid hormone

pill for several weeks or you get a shot of TSH (as

described above for the thyroglobulin test). Most

people need to avoid eating shellfish and iodized

salt for a week or two before the scan. Your doctor

gives you a very small dose of radioactive iodine or

another radioactive substance. The radioactive

substance is taken up by cancer cells (if any cancer

cells are present). Cancer cells show up on the scan.
26

• PET scan: Your doctor uses a PET scan to find

cancer that has returned. You receive an injection of

a small amount of radioactive sugar. A machine

makes computerized pictures of the sugar being

used by cells in the body. Cancer cells use sugar

faster than normal cells, and areas with cancer look

brighter on the pictures.

• CT scan: A CT scan may show whether cancer has

returned.

• MRI: MRI may show whether cancer has returned.

You may want to read the NCI booklet Facing

Forward Series: Life After Cancer Treatment. It

answers questions about follow-up care and other

concerns. Page 40 tells how to get NCI booklets.

Sources of Support

Learning that you have a serious disease such as

thyroid cancer is not easy. You may worry about caring

for your family, keeping your job, or continuing daily

activities. Concerns about treatments and managing

side effects, hospital stays, and medical bills are also

common.

You may want to ask your doctor these

questions after you have finished treatment:

• How often will I need checkups?

• Which follow-up tests do you suggest for me?

Do I need to avoid iodized salt and other

sources of iodine before any of these tests?

• Between checkups, what health problems or

symptoms should I tell you about?
27

It may help to share your feelings with family,

friends, a member of your health care team, or another

person with cancer. Here’s where you can go for

support:

• Doctors, nurses, and other members of your health

care team can answer questions about treatment,

working, or other activities.

• Social workers, counselors, or members of the

clergy can be helpful if you want to talk about your

feelings or concerns. Often, social workers can

suggest resources for financial aid, transportation,

home care, or emotional support.
28

• Support groups can also help. In these groups,

patients or their family members meet with other

patients or their families to share what they have

learned about coping with the disease and the effects

of treatment. Groups may offer support in person,

over the telephone, or on the Internet. You may want

to talk with a member of your health care team

about finding a support group.

• Information specialists at 1–800–4–CANCER and

at LiveHelp (http://www.cancer.gov/help) can help

you locate programs, services, and publications.

They can send you a list of organizations that offer

services to people with cancer.

For tips on coping, you may want to read the NCI

booklet Taking Time: Support for People With Cancer.

Page 40 tells how to get NCI booklets.

The Promise of Cancer Research

Doctors all over the country are conducting many

types of clinical trials (research studies in which people

volunteer to take part). Clinical trials are designed to

answer important questions and to find out whether

new approaches are safe and effective. Research

already has led to advances in the diagnosis and

treatment of thyroid cancer. Researchers continue to

search for new and better ways to treat thyroid cancer.

People who join clinical trials may be among the

first to benefit if a new approach is effective. And even

if the people in a trial do not benefit directly, they may

still make an important contribution by helping doctors

learn more about thyroid cancer and how to control it.

Although clinical trials may pose some risks,

researchers do all they can to protect their patients.
NCI’s Web site includes a section on clinical trials

at http://www.cancer.gov/clinicaltrials. It has

general information about clinical trials as well as

detailed information about specific ongoing studies of

thyroid cancer. NCI’s Information Specialists at

1–800–4–CANCER or at LiveHelp at

http://www.cancer.gov/help can answer questions and

provide information about clinical trials.

If you’re interested in taking part in a clinical trial,

talk with your doctor. You may also want to read the

NCI booklet Taking Part in Cancer Treatment

Research Studies. This booklet describes how

treatment studies are carried out and explains their

possible benefits and risks. Page 40 tells how to get

NCI booklets.

Another agency of the Federal Government, the

National Institute of Diabetes and Digestive and

Kidney Diseases (NIDDK), conducts research on

diseases of the thyroid. NIDDK performs laboratory

studies and conducts clinical trials on thyroid cancer.

The Web site address of the NIDDK is

http://www.niddk.nih.gov.

You can find NCI and NIDDK clinical trials

described at http://www.clinicaltrials.gov. This Web

site provides the latest information about federally and

privately supported clinical trials.

29
Dictionary

A dictionary with thousands of terms is on the NCI

Web site at http://www.cancer.gov/dictionary.

Anaplastic thyroid cancer (A-nuh-PLAS-tik THY-royd

KAN-ser): A rare, aggressive type of thyroid cancer in

which the malignant (cancer) cells look very different

from normal thyroid cells.

Benign (beh-NINE): Not cancerous. Benign tumors

may grow larger but do not spread to other parts of the

body.

Biopsy (BY-op-see): The removal of cells or tissues for

examination by a pathologist. The pathologist may

study the tissue under a microscope or perform other

tests on the cells or tissue. When only a sample of

tissue is removed, the procedure is called an incisional

biopsy. When an entire lump or suspicious area is

removed, the procedure is called an excisional biopsy.

When a sample of tissue or fluid is removed with a

needle, the procedure is called a needle biopsy, core

biopsy, or fine-needle aspiration.

C cell: A type of cell in the thyroid. C cells make

calcitonin, a hormone that helps control the calcium

level in the blood.

Calcitonin (KAL-sih-TOH-nin): A hormone formed by

the C cells of the thyroid gland. It helps maintain a

healthy level of calcium in the blood. When the

calcium level is too high, calcitonin lowers it.

Calcium (KAL-see-um): A mineral found in teeth,

bones, and other body tissues.

Cancer (KAN-ser): A term for diseases in which

abnormal cells divide without control. Cancer cells can

invade nearby tissues and can spread to other parts of

the body through the blood and lymph systems.

30
Chemotherapy (KEE-moh-THAYR-uh-pee):

Treatment with drugs that kill cancer cells.

Clinical trial: A type of research study that tests how

well new medical approaches work in people. These

studies test new methods of screening, prevention,

diagnosis, or treatment of a disease. Also called a

clinical study.

CT scan: Computed tomography scan (kum-PYOO-ted

tuh-MAH-gruh-fee skan). A series of detailed pictures

of areas inside the body taken from different angles;

the pictures are created by a computer linked to an

x-ray machine. Also called computerized tomography

and computerized axial tomography (CAT) scan.

Endocrinologist (en-duh-krih-NAH-loh-jist): A doctor

who specializes in diagnosing and treating hormone

disorders.

External radiation therapy (RAY-dee-AY-shun):

Radiation therapy that uses a machine to aim highenergy rays at the cancer. Also called external-beam

radiation.

Familial medullary thyroid cancer (fuh-MIH-lee-ul

MED-yoo-LAYR-ee): An inherited form of medullary

thyroid cancer (cancer that forms in the cells of the

thyroid that make the hormone calcitonin).

Familial polyposis (fuh-MIH-lee-ul PAH-lee-POHsis): An inherited condition in which numerous polyps

(growths that protrude from mucous membranes) form

on the inside walls of the colon and rectum. It

increases the risk of colorectal cancer. Also called

familial adenomatous polyposis and FAP.

Fertility (fer-TIL-i-tee): The ability to produce

children.

Fine-needle aspiration (as-per-AY-shun): The removal

of tissue or fluid with a needle for examination under a

microscope. Also called needle biopsy.

31
32

Follicular thyroid cancer (fuh-LIH-kyoo-ler THYroyd KAN-ser): Cancer that develops from cells in the

follicular areas of the thyroid. One of the slowgrowing, highly treatable types of thyroid cancer.

Gene: The functional and physical unit of heredity

passed from parent to offspring. Genes are pieces of

DNA, and most genes contain the information for

making a specific protein.

Gland: An organ that makes one or more substances,

such as hormones, digestive juices, sweat, tears, saliva,

or milk.

Goiter (GOY-ter): An enlarged thyroid. It may be

caused by too little iodine in the diet or by other

conditions. Most goiters are not cancer.

Hormone: A chemical made by glands in the body.

Hormones circulate in the bloodstream and control the

actions of certain cells or organs. Some hormones can

also be made in a laboratory.

Hyperthyroidism (HY-per-THY-ROY-dih-zum): Too

much thyroid hormone. Symptoms include weight loss,

chest pain, cramps, diarrhea, and nervousness. Also

called overactive thyroid.

Hypothyroidism (HY-poh-THY-ROY-dih-zum): Too

little thyroid hormone. Symptoms include weight gain,

constipation, dry skin, and sensitivity to the cold. Also

called underactive thyroid.

Incision (in-SIH-zhun): A cut made in the body to

perform surgery.

Iodine (I-oh-dine): An element that is necessary for the

body to make thyroid hormone. It is found in shellfish

and iodized salt.

Isthmus (iz-muhs): A narrow part inside the body that

connects two larger structures.
Larynx (LAYR-inks): The area of the throat containing

the vocal cords and used for breathing, swallowing,

and talking. Also called the voice box.

Lobectomy (loh-BEK-toh-mee): Surgery to remove a

whole lobe (section) of an organ (such as a lung, liver,

brain, or thyroid gland).

Local therapy (THAYR-uh-pee): Treatment that affects

cells in the tumor and the area close to it.

Lymph node (limf): A rounded mass of lymphatic

tissue that is surrounded by a capsule of connective

tissue. Lymph nodes filter lymph (lymphatic fluid), and

they store lymphocytes (white blood cells). They are

located along lymphatic vessels. Also called a lymph

gland.

Lymph vessel (limf): A thin tube that carries lymph

(lymphatic fluid) and white blood cells through the

lymphatic system. Also called lymphatic vessel.

Malignant (muh-LIG-nunt): Cancerous. Malignant

tumors can invade and destroy nearby tissue and

spread to other parts of the body.

Medical oncologist (MEH-dih-kul on-KAH-loh-jist): 

A doctor who specializes in diagnosing and treating

cancer using chemotherapy, hormonal therapy, and

biological therapy. A medical oncologist often is the

main health care provider for someone who has cancer.

A medical oncologist also gives supportive care and

may coordinate treatment given by other specialists.

Medullary thyroid cancer (MED-yoo-LAYR-ee THYroyd KAN-ser): Cancer 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.

Metastasis (meh-TAS-tuh-sis): The spread of cancer

from one part of the body to another. A tumor formed

by cells that have spread is called a “metastatic tumor”

33
or a “metastasis.” The metastatic tumor contains cells

that are like those in the original (primary) tumor. The

plural form of metastasis is metastases (meh-TAS-tuhSEEZ).

Metastatic (meh-tuh-STA-tik): Having to do with

metastasis, which is the spread of cancer from one part

of the body to another.

MRI: Magnetic resonance imaging (mag-NEH-tik

REH-zuh-nunts IH-muh-jing). A procedure in which

radio waves and a powerful magnet linked to a

computer are used to create detailed pictures of areas

inside the body. These pictures can show the difference

between normal and diseased tissue. MRI makes better

images of organs and soft tissue than other scanning

techniques, such as computed tomography (CT) or

x-ray. Also called nuclear magnetic resonance imaging

(NMRI).

Multiple endocrine neoplasia syndrome (MUL-tih-pul

EN-doh-krin NEE-oh-PLAY-zhuh SIN-drome): MEN.

An inherited condition that may result in the

development of cancers of the endocrine system

(hormone-releasing tissues, such as the thyroid and

pancreas). There are several types of multiple

endocrine neoplasia syndrome, and patients with each

type may develop different types of cancer. The altered

genes that cause each type can be detected with a

blood test. Also called MEN syndrome.

Nodule (NOD-yool): A growth or lump that may be

cancerous or noncancerous.

Oncology nurse (on-KAH-loh-jee): A nurse who

specializes in treating and caring for people who have

cancer.

Papillary thyroid cancer (PA-pih-LAYR-ee THY-royd

KAN-ser): Cancer that forms in follicular cells in the

thyroid and grows in small finger-like shapes. It grows

slowly, is more common in women than in men, and

34
often occurs before age 45. It is the most common type

of thyroid cancer.

Parathyroid gland (PAYR-uh-THY-royd): One of four

pea-sized glands found on the surface of the thyroid.

The parathyroid hormone made by these glands

increases the calcium level in the blood.

Pathologist (puh-THAH-loh-jist): A doctor who

identifies diseases by studying cells and tissues under a

microscope.

PET scan: Positron emission tomography scan (PAHzih-tron ee-MIH-shun toh-MAH-gruh-fee skan). A

procedure in which a small amount of radioactive

glucose (sugar) is injected into a vein, and a scanner is

used to make detailed, computerized pictures of areas

inside the body where the glucose is used. Because

cancer cells often use more glucose than normal cells,

the pictures can be used to find cancer cells in the

body.

Radiation (RAY-dee-AY-shun): Energy released in the

form of particles or electromagnetic waves. Common

sources of radiation include radon gas, cosmic rays

from outer space, and medical x-rays.

Radiation oncologist (RAY-dee-AY-shun on-KAHloh-jist): A doctor who specializes in using radiation to

treat cancer.

Radiation therapy (RAY-dee-AY-shun THAYRuh-pee): The use of high-energy radiation from x-rays,

gamma rays, neutrons, and other sources to kill cancer

cells and shrink tumors. Radiation may come from a

machine outside the body (external beam radiation

therapy), or it may come from radioactive material

placed in the body near cancer cells (internal radiation

therapy). Systemic radiation therapy uses a radioactive

substance, such as a radiolabeled monoclonal antibody,

that circulates throughout the body. Also called

radiotherapy and irradiation.

35
Radioactive fallout (RAY-dee-oh-AK-tiv): Airborne

radioactive particles that fall to the ground during and

after an atomic bombing, nuclear weapons test, or

nuclear plant accident.

Radioactive iodine (RAY-dee-oh-AK-tiv I-oh-dine): A

radioactive form of iodine, often used for imaging tests

or to treat overactive thyroid, thyroid cancer, and

certain other cancers. For imaging tests, the patient

swallows a small dose of radioactive iodine that

collects in thyroid cells and certain kinds of tumors and

can be detected by a scanner. To treat thyroid cancer,

the patient swallows a large dose of radioactive iodine,

which kills thyroid cells. 

Registered dietitian (dy-eh-TIH-shun): A health

professional with special training in the use of diet and

nutrition to keep the body healthy. A registered

dietitian may help the medical team improve the

nutritional health of a patient.

Surgeon: A doctor who removes or repairs a part of the

body by operating on the patient.

Surgery (SER-juh-ree): A procedure to remove or

repair a part of the body or to find out whether disease

is present. An operation.

Surgical biopsy (SER-jih-kul BY-op-see): The removal

of tissues by a surgeon for examination by a

pathologist. The pathologist may study the tissue under

a microscope.

Systemic therapy (sis-TEH-mik THAYR-uh-pee):

Treatment using substances that travel through the

bloodstream, reaching and affecting cells all over the

body.

Thyroglobulin (THIGH-roe-GLOB-yoo-lin): The form

that thyroid hormone takes when stored in the cells of

the thyroid. If the thyroid has been removed,

thyroglobulin should not show up on a blood test.

36
37

Doctors measure the thyroglobulin level in blood to

detect thyroid cancer cells that remain in the body after

treatment.

Thyroid (THY-royd): A gland located beneath the

voice box (larynx) that makes thyroid hormone and

calcitonin. The thyroid helps regulate growth and

metabolism.

Thyroid follicular cell (THY-royd fuh-LIK-yoo-ler): A

type of cell in the thyroid. Thyroid follicular cells make

thyroid hormone.

Thyroid hormone (THY-royd HOR-mone): A hormone

that affects heart rate, blood pressure, body

temperature, and weight. Thyroid hormone is made by

the thyroid gland and can also be made in the

laboratory.

Thyroid hormone treatment (THY-royd HOR-mone):

Treatment with thyroid hormone, which is a hormone

that affects heart rate, blood pressure, body

temperature, and weight.

Thyroid-stimulating hormone (THY-royd STIM-yooLAY-ting HOR-mone): TSH. A hormone produced by

the pituitary gland. TSH stimulates the release of

thyroid hormone from thyroglobulin. It also stimulates

the growth of thyroid follicular cells. An abnormal

TSH level may mean that the thyroid hormonal

regulation system is out of control, usually as a result

of a benign condition (hyperthyroidism or

hypothyroidism).

Thyroidectomy (THY-roy-DEK-toh-mee): Surgery to

remove part or all of the thyroid.

Thyroidologist (THY-roy-DOL-oh-jist): A medical

doctor who specializes in thyroid diseases.
38

Tumor (TOO-mer): An abnormal mass of tissue that

results when cells divide more than they should or do

not die when they should. Tumors may be benign (not

cancerous), or malignant (cancerous). Also called

neoplasm.

Ultrasound (UL-truh-SOWND): A procedure in which

high-energy sound waves (ultrasound) are bounced off

internal tissues or organs and make echoes. The echo

patterns are shown on the screen of an ultrasound

machine, forming a picture of body tissues called a

sonogram. Also called ultrasonography.

X-ray: A type of high-energy radiation. In low doses,

x-rays are used to diagnose diseases by making

pictures of the inside of the body. In high doses, x-rays

are used to treat cancer.
39

National Cancer Institute Information

Resources

You may want more information for yourself, your

family, and your doctor. The following NCI services

are available to help you.

Telephone

NCI’s Cancer Information Service (CIS) provides

accurate, up-to-date information about cancer to

patients and their families, health professionals, and the

general public. Information specialists translate the

latest scientific information into plain language and

respond in English or Spanish. Calls to the CIS are

confidential and free.

Telephone: 1–800–4–CANCER (1–800–422–6237)

TTY: 1–800–332–8615

Internet

NCI’s Web site provides information from numerous

NCI sources. It offers current information about cancer

prevention, screening, diagnosis, treatment, genetics,

supportive care, and ongoing clinical trials. It has

information about NCI’s research programs, funding

opportunities, and cancer statistics.

Web site: http://www.cancer.gov

Spanish Web site: http://www.cancer.gov/espanol

If you’re unable to find what you need on the Web

site, contact NCI staff. Use the online contact form at

http://www.cancer.gov/contact or send an email to

cancergovstaff@mail.nih.gov.

Also, information specialists provide live, 

online assistance through LiveHelp at

http://www.cancer.gov/help.
National Cancer Institute Publications

NCI provides information about cancer, including

the publications mentioned in this booklet. Many are

available in both English and Spanish. 

You may order these materials by telephone, on the

Internet, or by mail. You may also read them online

and print your own copy.

• By telephone: People in the United States and its

territories may order these and other NCI

publications by calling the NCI’s Cancer

Information Service at 1–800–4–CANCER.

• On the Internet: Many NCI publications may be

viewed, downloaded, and ordered from

http://www.cancer.gov/publications on the

Internet. People in the United States and its

territories may use this Web site to order printed

copies. This Web site also explains how people

outside the United States can mail or fax their

requests for NCI booklets.

• By mail: NCI publications may be ordered by

writing to the address below:

Publications Ordering Service

National Cancer Institute

Suite 3035A

6116 Executive Boulevard, MSC 8322

Bethesda, MD 20892–8322

40
Treatment

• Radiation Therapy and You (also available in

Spanish: La radioterapia y usted)

• Radiation Therapy for Cancer: Questions and

Answers

• Chemotherapy and You (also available in Spanish:

La quimioterapia y usted)

• How To Find a Doctor or Treatment Facility If You

Have Cancer (also available in Spanish: Cómo

encontrar a un doctor o un establecimiento de

tratamiento si usted tiene cáncer)

Living With Cancer

• Eating Hints for Cancer Patients (also available in

Spanish: Consejos de alimentación para pacientes

con cáncer)

• Pain Control (also available in Spanish: Control del

dolor)

• Facing Forward Series: Life After Cancer Treatment

(also available in Spanish: Siga adelante: la vida

después del tratamiento del cáncer)

• Facing Forward Series: Ways You Can Make a

Difference in Cancer

• Taking Time: Support for People with Cancer

• Coping with Advanced Cancer

• When Cancer Returns

Clinical Trials

• Taking Part in Cancer Treatment Research Studies

41
Complementary Medicine

• Thinking About Complementary & Alternative

Medicine: A guide for people with cancer

• Complementary and Alternative Medicine in Cancer

Treatment: Questions and Answers (also available in

Spanish: La medicina complementaria y alternativa

en el tratamiento del cáncer: preguntas y

respuestas)

Radioactive Iodine Fallout

• Get the Facts About Exposure to I-131 Radiation

• Making Choices: Screening for Thyroid Disease

• I-131 and Radioactive Fallout: Questions and

Answers

Caregivers

• When Someone You Love Is Being Treated for

Cancer: Support for Caregivers

• When Someone You Love Has Advanced Cancer:

Support for Caregivers

• Facing Forward: When Someone You Love Has

Completed Cancer Treatment

42
¿Necesita información en español?

Llame al Servicio de Información sobre el

Cáncer y hable en español con un especialista en

información. El número es 1–800–422–6237.

O visite el sitio de Internet del Instituto

Nacional del Cáncer en

http://www.cancer.gov/espanol. 

The National Cancer Institute

The National Cancer Institute (NCI) is part of the

National Institutes of Health. NCI conducts and supports

basic and clinical research in the search for better ways to

prevent, diagnose, and treat cancer. NCI also supports 

the training of scientists and is responsible for

communicating its research findings to the medical

community and the public.

Copyright permission

The written text of NCI material is in the public

domain. It is not subject to copyright restrictions. You do

not need our permission to reproduce or translate NCI

written text. However, we would appreciate a credit line

and a copy of your translations. 

Private sector designers, photographers, and illustrators

retain copyrights to artwork they develop under contract to

NCI. You must have permission to use or reproduce these

materials. In many cases, artists will grant permission, but

they may require a credit line and/or usage fees. To inquire

about permission to reproduce NCI artwork, please write

to: Office of Communications and Education, Publications

Support Branch, National Cancer Institute, 6116 Executive

Boulevard, Room 3066, MSC 8323, Rockville, MD

20892–8323.
NIH Publication No. 07-4994

Revised August 2007

Printed September 2007