Thyroid cancer is a growth of cells that starts in the thyroid. The thyroid is a butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid produces hormones that regulate heart rate, blood pressure, body temperature and weight.
Thyroid cancer might not cause any symptoms at first. But as it grows, it can cause signs and symptoms, such as swelling in your neck, voice changes and difficulty swallowing.
Several types of thyroid cancer exist. Most types grow slowly, though some types can be very aggressive. Most thyroid cancers can be cured with treatment.
Thyroid cancer rates seem to be increasing. The increase may be caused by improved imaging technology that allows health care providers to find small thyroid cancers on CT and MRI scans done for other conditions (incidental thyroid cancers). Thyroid cancers found in this way are usually small cancers that respond well to treatments.
Most thyroid cancers don't cause any signs or symptoms early in the disease. As thyroid cancer grows, it may cause:
If you experience any signs or symptoms that worry you, make an appointment with your health care provider.
Thyroid cancer happens when cells in the thyroid develop changes in their DNA. A cell's DNA contains the instructions that tell the cell what to do. The changes, which doctors call mutations, tell the cells to grow and multiply rapidly. The cells go on living when healthy cells would naturally die. The accumulating cells form a mass called a tumor.
The tumor can grow to invade nearby tissue and can spread (metastasize) to the lymph nodes in the neck. Sometimes the cancer cells can spread beyond the neck to the lungs, bones and other parts of the body.
For most thyroid cancers, it's not clear what causes the DNA changes that cause the cancer.
Thyroid cancer is classified into types based on the kinds of cells found in the tumor. Your type is determined when a sample of tissue from your cancer is examined under a microscope. The type of thyroid cancer is considered in determining your treatment and prognosis.
Types of thyroid cancer include:
Factors that may increase the risk of thyroid cancer include:
Thyroid cancer can return despite successful treatment, and it can even come back if you've had your thyroid removed. This could happen if cancer cells spread beyond the thyroid before it's removed.
Most thyroid cancers aren't likely to recur, including the most common types of thyroid cancer — papillary thyroid cancer and follicular thyroid cancer. Your health care provider can tell you if your cancer has an increased risk of recurring based on the particulars of your cancer.
Recurrence is more likely if your cancer is aggressive or if it grows beyond your thyroid. When thyroid cancer recurrence happens, it's usually found in the first five years after your initial diagnosis.
Thyroid cancer that comes back still has a good prognosis. It's often treatable, and most people will have successful treatment.
Thyroid cancer may recur in:
Your health care provider may recommend periodic blood tests or thyroid scans to check for signs that your cancer has returned. At these appointments, your provider may ask if you've experienced any signs and symptoms of thyroid cancer recurrence, such as:
Thyroid cancer sometimes spreads to nearby lymph nodes or to other parts of the body. The cancer cells that spread might be found when you're first diagnosed or they might be found after treatment. The great majority of thyroid cancers don't ever spread.
When thyroid cancer spreads, it most often travels to:
Thyroid cancer that spreads might be detected on imaging tests, such as CT and MRI, when you're first diagnosed with thyroid cancer. After successful treatment, your health care provider might recommend follow-up appointments to look for signs that your thyroid cancer has spread. These appointments might include nuclear imaging scans that use a radioactive form of iodine and a special camera to detect thyroid cancer cells.
Doctors aren't sure what causes the gene changes that lead to most thyroid cancers, so there's no way to prevent thyroid cancer in people who have an average risk of the disease.
Adults and children with an inherited gene that increases the risk of medullary thyroid cancer may consider 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.
A medication that blocks the effects of radiation on the thyroid is sometimes provided to people living near nuclear power plants in the United States. The medication (potassium iodide) could be used in the unlikely event of a nuclear reactor accident. If you live within 10 miles of a nuclear power plant and are concerned about safety precautions, contact your state or local emergency management department for more information.
Tests and procedures used to diagnose thyroid cancer include:
Ultrasound imaging. Ultrasound uses high-frequency sound waves to create pictures of body structures. To create an image of the thyroid, the ultrasound transducer is placed on your lower neck.
The way a thyroid nodule looks on an ultrasound image helps your provider determine if it's likely to be cancer. Signs that a thyroid nodule is more likely to be cancerous include calcium deposits (microcalcifications) within the nodule and an irregular border around the nodule. If there's a high likelihood that a nodule might be cancerous, additional tests are needed to confirm the diagnosis and determine what type of thyroid cancer is present.
Your provider may also use ultrasound to create images of the lymph nodes in the neck (lymph node mapping) to look for signs of cancer.
Removing a sample of thyroid tissue. During a fine-needle aspiration biopsy, your provider inserts a long, thin needle through your skin and into the thyroid nodule. Ultrasound imaging is typically used to precisely guide the needle. Your provider uses the needle to remove some cells from the thyroid. The sample is sent to a lab for analysis.
In the lab, a doctor who specializes in analyzing blood and body tissue (pathologist) examines the tissue sample under a microscope and determines whether cancer is present. The results aren't always clear. Some types of thyroid cancer, particularly follicular thyroid cancer and Hurthle cell thyroid cancer, are more likely to have uncertain results (indeterminate thyroid nodules). Your provider may recommend another biopsy procedure or an operation to remove the thyroid nodule for testing. Specialized tests of the cells to look for gene changes (molecular marker testing) also can be helpful.
An imaging test that uses a radioactive tracer. A radioactive iodine scan uses a radioactive form of iodine and a special camera to detect thyroid cancer cells in your body. It's most often used after surgery to find any cancer cells that might remain. This test is most helpful for papillary and follicular thyroid cancers.
Healthy thyroid cells absorb and use iodine from the blood. Some types of thyroid cancer cells do this, too. When the radioactive iodine is injected in a vein or swallowed, any thyroid cancer cells in the body will take up the iodine. Any cells that take up the iodine are shown on the radioactive iodine scan images.
Your health care team uses information from your tests and procedures to determine the extent of the cancer and assign it a stage. Your cancer's stage tells your care team about your prognosis and helps them select the treatment that's most likely to help you.
Cancer stage is indicated with a number between 1 and 4. A lower number usually means the cancer is likely to respond to treatment, and it often means the cancer only involves the thyroid. A higher number means the diagnosis is more serious, and the cancer may have spread beyond the thyroid to other parts of the body.
Different types of thyroid cancer have different sets of stages. For instance, medullary and anaplastic thyroid cancers each have their own set of stages. Differentiated thyroid cancer types, including papillary, follicular, Hurthle cell and poorly differentiated, share a set of stages. For differentiated thyroid cancers, your stage may vary based on your age.
Your thyroid cancer treatment options depend on the type and stage of your thyroid cancer, your overall health, and your preferences.
Most people diagnosed with thyroid cancer have an excellent prognosis, as most thyroid cancers can be cured with treatment.
Treatment might not be needed right away for very small papillary thyroid cancers (papillary microcarcinomas) because these cancers have a low risk of growing or spreading. As an alternative to surgery or other treatments, you might consider active surveillance with frequent monitoring of the cancer. Your health care provider might recommend blood tests and an ultrasound exam of your neck once or twice a year.
In some people, the cancer might never grow and never require treatment. In others, growth may eventually be detected and treatment can begin.
Most people with thyroid cancer that requires treatment will undergo surgery to remove part or all of the thyroid. Which operation your health care team might recommend depends on your type of thyroid cancer, the size of the cancer and whether the cancer has spread beyond the thyroid to the lymph nodes. Your care team also considers your preferences when creating a treatment plan.
Operations used to treat thyroid cancer include:
To access the thyroid, surgeons usually make a cut (incision) in the lower part of the neck. The size of the incision depends on your situation, such as the type of operation and the size of your thyroid gland. Surgeons usually try to place the incision in a skin fold where it will be difficult to see as it heals and becomes a scar.
Thyroid surgery carries a risk of bleeding and infection. Damage to your parathyroid glands also can occur during surgery, which can lead to low calcium levels in your body.
There's also a risk that the nerves connected to your vocal cords might not work as expected after surgery, which can cause hoarseness and voice changes. Treatment can improve or reverse nerve problems.
After surgery, you can expect some pain as your body heals. How long it takes to recover will depend on your situation and the type of surgery you had. Most people start to feel recovered in 10 to 14 days. Some restrictions on your activity might continue. For instance, your surgeon might recommend staying away from strenuous activity for a few more weeks.
After surgery to remove all or most of the thyroid, you might have blood tests to see if all of the thyroid cancer has been removed. Tests might measure:
These blood tests are also used to look for signs of cancer recurrence.
Thyroid hormone therapy is a treatment to replace or supplement the hormones produced in the thyroid. Thyroid hormone therapy medication is usually taken in pill form. It can be used to:
Replace thyroid hormones after surgery. If your thyroid is removed completely, you'll need to take thyroid hormones for the rest of your life to replace the hormones your thyroid made before your operation. This treatment replaces your natural hormones, so there shouldn't be any side effects once your health care team finds the dose that's right for you.
You might also need thyroid hormone replacement after having surgery to remove part of the thyroid, but not everyone does. If your thyroid hormones are too low after surgery (hypothyroidism), your health care team might recommend thyroid hormones.
Radioactive iodine treatment uses a form of iodine that's radioactive to kill thyroid cells and thyroid cancer cells that might remain after surgery. It's most often used to treat differentiated thyroid cancers that have a risk of spreading to other parts of the body.
You might have a test to see if your cancer is likely to be helped by radioactive iodine, since not all types of thyroid cancer respond to this treatment. Differentiated thyroid cancer types, including papillary, follicular and Hurthle cell, are more likely to respond. Anaplastic and medullary thyroid cancers usually aren't treated with radioactive iodine.
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.
Which side effects you experience will depend on the dose of radioactive iodine you receive. Higher doses may cause:
Most of the radioactive iodine leaves your body in your urine in the first few days after treatment. You'll be given instructions for precautions you need to take during that time 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.
Alcohol ablation, which is also called ethanol ablation, involves using a needle to inject alcohol into small areas of thyroid cancer. Ultrasound imaging is used to precisely guide the needle. The alcohol causes the thyroid cancer cells to shrink.
Alcohol ablation may be an option to treat small areas of thyroid cancer, such as cancer that's found in a lymph node after surgery. Sometimes it's an option if you aren't healthy enough for surgery.
Aggressive thyroid cancers that grow more quickly may require additional treatment options to control the disease. Options might include:
Targeted drug therapy. Targeted drug treatments focus on specific chemicals present within cancer cells. By blocking these chemicals, targeted drug treatments can cause cancer cells to die. Some of these treatments come in pill form and some are given through a vein.
There are many different targeted therapy drugs for thyroid cancer. Some target the blood vessels that cancer cells make to bring nutrients that help the cells survive. Other drugs target specific gene changes. Your provider may recommend special tests of your cancer cells to see which treatments might help. Side effects will depend on the specific drug you take.
Palliative care is specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness. Palliative care specialists work with you, your family and your health care team to provide an extra layer of support that complements your ongoing care.
Palliative care can be used while undergoing other aggressive treatments, such as surgery, chemotherapy or radiation therapy. Increasingly, palliative care is being offered early in the course of cancer treatment.
When palliative care is used along with all of the other appropriate treatments, people with cancer may feel better, have a better quality of life and live longer.
Palliative care is provided by a team of doctors, nurses and other specially trained professionals. Palliative care teams aim to improve quality of life for people with cancer and their families.
After your thyroid cancer treatment ends, your provider may recommend follow-up tests and procedures to look for signs that your cancer has returned. You may have follow-up appointments once or twice a year for several years after treatment ends.
Which tests you need will depend on your situation. Follow-up tests may include:
It can take time to accept and learn to cope with a thyroid cancer diagnosis. Everyone eventually finds their own way of coping. Until you find what works for you, consider trying to:
If you have signs and symptoms that worry you, start by seeing your family health care provider. If your provider suspects that 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 information to discuss, it's a good idea to be prepared. Here's some information to help you get ready, and what to expect.
Your time with your provider 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 include:
If any additional questions occur to you during your visit, don't hesitate to ask.
Your provider 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 provider may ask:
