Taking daily pills of thyroid hormone (thyroid hormone therapy) can serve 2 purposes:
It can help maintain the body’s normal metabolism (by replacing missing thyroid hormone after surgery).
It can help stop any remaining cancer cells from growing (by lowering TSH levels).
After a thyroidectomy, the body can no longer make the thyroid hormone it needs, so patients must take thyroid hormone (levothyroxine) pills to replace the loss of the natural hormone.
Taking thyroid hormone may also help prevent some thyroid cancers from returning. Normal thyroid function is regulated by the pituitary gland. The pituitary makes a hormone called TSH that causes the thyroid gland to make thyroid hormone for the body. TSH also promotes growth of the thyroid gland and probably of thyroid cancer cells. The level of TSH, in turn, is regulated by how much thyroid hormone is in the blood. If the level of thyroid hormone is low, the pituitary makes more TSH. If the level of thyroid hormone is high, not as much TSH is needed, so the pituitary makes less of it.
Doctors have learned that by giving higher than normal doses of thyroid hormone, TSH levels can be kept very low. This may slow the growth of any remaining cancer cells and lower the chance of some thyroid cancers (especially high-risk cancers) coming back.
Possible side effects
Taking higher than normal levels of thyroid hormone seems to have few short-term side effects, but some doctors have expressed concerns about taking them for long periods of time. High levels of thyroid hormone can lead to problems with a rapid or irregular heartbeat. Over the long run, high doses of thyroid hormone can lead to weak bones (osteoporosis). Because of this, high doses of thyroid hormone may be reserved for people with differentiated thyroid cancers who are at high risk of recurrence.
External beam radiation therapy for thyroid cancer
External beam radiation therapy uses high-energy rays (or particles) to destroy cancer cells or slow their growth. A carefully focused beam of radiation is delivered from a machine outside the body. Generally, this type of radiation treatment is not used for cancers that take up iodine (that is, most differentiated thyroid cancers), which are better treated with radioiodine therapy. It is more often used as part of the treatment for medullary thyroid cancer and anaplastic thyroid cancer.
When a cancer that does not take up iodine has spread beyond the thyroid, external radiation treatment may help treat the cancer or reduce the chance of the disease coming back in the neck after surgery. If a cancer does not respond to radioiodine therapy, external radiation therapy may be used to treat local neck recurrence or distant metastases that are causing pain or other symptoms.
External beam radiation therapy is usually given 5 days a week for several weeks. Before your treatments start, the medical team will take careful measurements to find the correct angles for aiming the radiation beams and the proper dose of radiation. The treatment itself is painless and much like getting a regular x-ray. Each treatment lasts only a few minutes, although the setup time — getting you into place for treatment — usually takes longer.
Possible side effects
The main drawback of this treatment is that the radiation can destroy nearby healthy tissue along with the cancer cells. Some patients get skin changes similar to a sunburn, but this slowly fades away. Trouble swallowing, dry mouth, hoarseness, and fatigue are also potential side effects of external beam radiation therapy aimed at or near the thyroid.
To reduce the risk of side effects, doctors carefully figure out the exact dose needed and aim the beam as accurately as they can to hit the target.
Chemotherapy for thyroid cancer
Chemotherapy (chemo) uses anti-cancer drugs that are injected into a vein or muscle, or are taken by mouth. Chemotherapy is systemic therapy, which means that the drug enters the bloodstream and travels throughout the body to reach and destroy cancer cells.
Chemotherapy is seldom helpful for most types of thyroid cancer, but fortunately it is not needed in most cases. It is combined with external beam radiation therapy for anaplastic thyroid cancer and is sometimes used for other advanced cancers that no longer respond to other treatments.
Possible side effects
Chemo drugs attack cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow, the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemotherapy, which can lead to side effects.
The side effects of chemotherapy depend on the type and dose of drugs given and the length of time they are taken. Common side effects of chemo include:
Loss of appetite
Nausea and vomiting
Increased chance of infections (from too few white blood cells)
Easy bruising or bleeding (from too few low blood platelets)
Fatigue (from too few low red blood cells)
These side effects are usually short-term and go away after treatment is finished. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting.
Some chemotherapy drugs may have other specific side effects that require monitoring. For example, doxorubicin (one of the most common chemo drugs used in thyroid cancer) can affect heart function. Therefore a patient taking doxorubicin will get regular heart function tests like echocardiograms.
Targeted therapy for thyroid cancer
Researchers have begun to develop newer drugs that specifically target the changes inside cells that cause them to become cancerous. Unlike standard chemotherapy drugs, which work by attacking rapidly growing cells in general (including cancer cells), these drugs attack one or more specific targets on cancer cells.
Targeted drugs for medullary thyroid cancer
Doctors have been especially interested in finding targeted drugs to treat medullary thyroid cancer (MTC) because thyroid hormone-based treatments (including radioactive iodine therapy) are not effective against these cancers.
Vandetanib (Caprelsa®) is a targeted drug taken as a pill once a day. In patients with advanced MTC, vandetanib stops cancers from growing for an average of about 6 months, although it is not yet clear if it can help people live longer. Some common side effects of vandetanib include diarrhea, rash, nausea, high blood pressure, headache, fatigue, decreased appetite, and belly (abdominal) pain. Rarely, it can also cause serious problems with heart rhythm and infection that can lead to death. Because of its potential side effects, doctors must get special training before they are allowed to prescribe this drug.
Cabozantinib (Cometriq™) is another targeted drug used to treat MTC. It is taken in pill form once a day. In MTC patients, cabozantinib has been shown to help stop cancers from growing for about 7 months longer than a sugar pill. So far, though, it has not been shown to help patients live longer.
Common side effects include diarrhea, constipation, belly pain, mouth sores, decreased appetite, nausea, weight loss, fatigue, high blood pressure, loss of hair color, and hand-foot syndrome (redness, pain, and swelling of the hands and feet). Rarely, this drug can also cause serious side effects, such as severe bleeding and holes in the intestine.
Several other targeted drugs have shown promising early results against MTC as well. Some of these, such as sorafenib (Nexavar®) and sunitinib (Sutent®) are already used to treat other types of cancer. Doctors may try giving these drugs if other treatments, including vandetanib and cabozantinib, aren’t helpful.
Targeted drugs for papillary or follicular thyroid cancer
Fortunately, most of these cancers can be treated effectively with surgery and radioactive iodine therapy, so there is less need for other drugs to treat them. But for cancers in which these treatments aren’t effective, targeted drugs such as sorafenib, sunitinib, pazopanib (Votrient®), and vandetanib have shown some early promise and may be helpful.
Treatment of thyroid cancer by type and stage
The type of treatment your doctor will recommend depends on the type and stage of the cancer and on your overall health. This section discusses the typical treatment options for each type and stage of thyroid cancer, but your doctor may have reasons for suggesting a different treatment plan. Don’t hesitate to ask him or her questions about your treatment options.
Papillary carcinoma and its variants
Stages I and II: These cancers are treated with surgery. Most often this is a thyroidectomy, but lobectomy (removal of only the affected side of the thyroid gland) may be an option for some people. Radioiodine treatment is sometimes used after thyroidectomy, but the cure rate with surgery alone is excellent. If the cancer does come back, radioiodine treatment can still be offered.
People who have a thyroidectomy will need to take daily thyroid hormone (levothyroxine) pills. If radioactive iodine treatment is planned, the start of thyroid hormone therapy may be delayed until the treatment is finished (usually about 6 weeks after surgery).
Some doctors recommend central compartment neck dissection (surgical removal of lymph nodes next to the thyroid) along with removal of the thyroid. Although this operation has not been shown to improve cancer survival, it might lower the risk of cancer coming back in the neck area. Because removing the lymph nodes allows them to be checked for cancer under the microscope, this surgery also makes it easier to accurately stage the cancer.
Stages III and IV: Most patients have the thyroid removed (either a near-total or total thyroidectomy) along with nearby lymph nodes. Some doctors recommend central compartment neck dissection (surgical removal of lymph nodes next to the thyroid). Although this has not been shown to improve survival, it might lower the risk of cancer coming back in the neck area. It also makes it easier to accurately stage the cancer. If cancer has spread to other neck lymph nodes, a modified radical neck dissection (a more extensive removal of lymph nodes from the neck) is often done.
Radioiodine therapy is often used to destroy any remaining thyroid tissue after surgery and to try to treat any cancer remaining in the neck or elsewhere in the body that takes up iodine. Distant metastases may need to be treated with external beam radiation therapy, targeted therapy, or chemotherapy if they do not respond to radioactive iodine.
Thyroid hormone therapy is used as well, although it’s not started until after radioiodine treatment.
Recurrent cancer: Treatment of cancer that comes back after initial therapy depends mainly on where the cancer is, although other factors may be important as well. The recurrence may be found by either blood tests or imaging tests such as radioiodine scans.
If the cancer can be located and appears to be resectable (removable), surgery is often used. If the cancer shows up on a radioiodine scan (meaning the cells are taking up iodine), radioiodine therapy may be used, either alone or with surgery. If the cancer does not show up on the radioiodine scan but is found by other imaging tests such as an MRI or PET scan, external radiation may be used.
Targeted therapy or chemotherapy may be tried if the cancer has spread to several places and radioiodine and other treatments are not helpful, but doctors are still trying to find effective drugs for this disease. Because these cancers can be hard to treat, another option is taking part in a clinical trial of newer treatments.
Follicular and Hürthle cell carcinoma
Stages I to IV: Most doctors recommend near-total or total thyroidectomy for these types of thyroid cancer, although lobectomy may be an option for some patients with very early stage cancers.
Thyroidectomy makes radioactive iodine treatment afterward more effective. As with papillary cancer, some lymph nodes usually are removed and examined. If cancer has spread to lymph nodes, a central compartment or modified radical neck dissection (surgical removal of lymph nodes from the neck) may be done. Because the thyroid is removed, patients will need thyroid hormone therapy as well, although it is often not started right away.
Radioiodine scanning is usually done after surgery to look for areas still taking up iodine. Spread to nearby lymph nodes and to distant sites that shows up on the scan can be treated by radioactive iodine. For cancers that don’t take up iodine, external beam radiation therapy may help treat the tumor or prevent it from growing back in the neck.
Distant metastases may need to be treated with external beam radiation therapy, targeted therapy, or chemotherapy if they do not respond to radioactive iodine. Another option is taking part in a clinical trial of newer treatments.
Recurrent cancer: The options for treating these cancers that come back after initial treatment are basically the same as they are for recurrent papillary cancer (see above).
Medullary thyroid carcinoma
Most doctors advise that patients diagnosed with medullary thyroid carcinoma (MTC) be tested for other tumors that are typically seen in patients with the MEN 2 syndromes, such as pheochromocytoma and parathyroid tumors. Screening for pheochromocytoma is particularly important, since the unknown presence of this tumor can make anesthesia and surgery extremely dangerous. If surgeons and anesthesiologists know about such tumors ahead of time, they can medically pre-treat the patient to make surgery safe.
Stages I and II: Total thyroidectomy is the main treatment for MTC and often cures patients with stage I or stage II MTC. Nearby lymph nodes are usually removed as well (central compartment or modified radical neck dissection). Because the thyroid gland is removed, thyroid hormone therapy is needed after surgery. For MTC, thyroid hormone therapy is meant to provide enough hormone to keep the patient healthy, but it does not reduce the risk that the cancer will come back.
Because MTC cells do not take up radioactive iodine, there is no role for radioactive iodine therapy in treating MTC. Still, some doctors give a dose of radioactive iodine to destroy any remaining normal thyroid tissue. If MTC cells are in or near the thyroid, this may affect them as well.
Stages III and IV: Surgery is the same as for stages I and II (usually after screening for MEN 2 syndrome and pheochromocytoma). Thyroid hormone therapy is given afterward. When the tumor is extensive and invades many nearby tissues or cannot be completely removed, external beam radiation therapy may be given after surgery to try to reduce the chance of recurrence in the neck.
For cancers that have spread to distant parts of the body, surgery, radiation therapy, or similar treatments may be used if possible. If these treatments can’t be used, vandetanib (Caprelsa), cabozantinib (Cometriq), or other targeted drugs may be tried. Chemotherapy may be another option. Because these cancers can be hard to treat, another option is taking part in a clinical trial of newer treatments.
Recurrent cancer: If the cancer recurs in the neck or elsewhere, surgery, external radiation therapy, targeted therapy (such as vandetanib or cabozantinib), or chemotherapy may be needed. Clinical trials of new treatments may be another option if standard treatments aren’t effective.
Genetic testing in medullary thyroid cancer: If you are told that you have MTC, even if you are the first one in the family to be diagnosed with this disease, ask your doctor about genetic counseling and testing. Genetic testing can find mutations in the RET gene, which is seen in cases of familial MTC and the MEN 2 syndromes.
If you have one of these mutations, it’s important that close family members (children, brothers, and sisters) be tested as well. Because almost all children and adults with mutations in this gene will develop MTC at some time, most doctors agree anyone who has a RET gene mutation should have their thyroid removed to prevent MTC soon after getting the test results. This includes children, since some hereditary forms of MTC affect children and pre-teens. Total thyroidectomy can prevent this cancer in people with RET mutations who have not yet developed it. Of course, this means that lifelong thyroid hormone replacement will be needed.
Surgery might or might not be used to treat this cancer, because it is often already widespread when it is diagnosed. If the cancer is confined to the area around the thyroid, which is rare, the entire thyroid and nearby lymph nodes may be removed. The goal of surgery is to remove as much cancer in the neck area as possible, ideally leaving no cancer tissue behind. Because of the way anaplastic carcinoma spreads, this is often difficult or not possible.
External beam radiation therapy may be used alone or combined with chemotherapy:
To try to shrink the cancer before surgery to increase the chance of complete tumor removal
After surgery to try to control any disease that remains in the neck
When the tumor is too large or widespread to be treated by surgery
If the cancer is causing (or may eventually cause) trouble breathing, a hole may be placed surgically in the front of the neck and into the windpipe to bypass the tumor and allow the patient to breathe more comfortably. This hole is called a tracheostomy.
For cancers that have spread to distant sites, chemotherapy may be used, sometimes along with radiation therapy if the cancer is not too widespread. Because these cancers can be hard to treat, clinical trials of newer treatments are an option as well.
What happens after treatment for thyroid cancer?
For many people with thyroid cancer, treatment may remove or destroy the cancer. Completing treatment can be both stressful and exciting. You may be relieved to finish treatment, but find it hard not to worry about cancer growing or coming back. (When cancer comes back after treatment, it is called recurrence.) This is a very common concern in people who have had cancer.
It may take a while before your fears lessen. But it may help to know that many cancer survivors have learned to live with this uncertainty and are leading full lives.
For some people, thyroid cancer may never go away completely. These people may get regular treatments with chemotherapy, radiation therapy, or other therapies to help keep the cancer in check. Learning to live with cancer as a more of a chronic disease can be difficult and very stressful. It has its own type of uncertainty.
If you have completed treatment, your doctors will still want to watch you closely. It is very important to go to all follow-up appointments. During these visits, your doctors will ask about symptoms, examine you, and might order blood tests or imaging tests such as radioiodine scans or ultrasounds. Follow-up is needed to check for cancer recurrence or spread, as well as possible side effects of certain treatments. This is the time for you to ask your health care team any questions you need answered and to discuss any concerns you might have.
Most people do very well after treatment, but follow-up care can continue for a lifetime. This is very important since most thyroid cancers grow slowly and can recur even 10 to 20 years after initial treatment. Your health care team will explain what tests you need and how often they should be done.
Papillary or follicular cancer: If you have had papillary or follicular cancer, and your thyroid gland has been completely removed or ablated, your doctors might do at least one radioactive iodine scan after treatment, especially if you are at higher risk for recurrence. This is usually done about 6 to 12 months later. If the result is negative, you will generally not need further scans unless you have symptoms or other abnormal test results.
Your blood will also be tested for TSH and thyroglobulin levels. Thyroglobulin is made by thyroid tissue, so after total thyroid removal and ablation it should be at very low levels in your blood. If the thyroglobulin level begins to rise, it may be a sign the cancer is coming back, and further testing will be done. This usually includes a radioactive iodine scan, and may include PET scans and other imaging tests.
For those with a low-risk, small papillary cancer that was treated by removing only one lobe of the thyroid, a physical exam by your doctor, as well as a thyroid ultrasound and periodic chest x-ray is typical.
Medullary thyroid cancer: If you had medullary thyroid cancer (MTC), your doctors will check the levels of calcitonin and carcinoembryonic antigen (CEA) in your blood. If these begin to rise, imaging tests such as an ultrasound of the neck or a CT or MRI scan will be done to look for any cancer coming back.
Each type of treatment for thyroid cancer has side effects that may last for a few months. Some, like the need for thyroid hormone pills, may be lifelong. You may be able to speed your recovery by being aware of the side effects before you start treatment. You might be able to take steps to reduce them and shorten the length of time they last. Don’t hesitate to tell your cancer care team about any symptoms or side effects that bother you so they can help you manage them.
If treatment for thyroid cancer is no longer working
If cancer keeps growing or comes back after one kind of treatment, it may be possible to try another treatment plan that might still cure the cancer, or at least shrink the tumors enough to help you live longer and feel better. But when a person has tried many different treatments and the cancer has not gotten any better, the cancer tends to become resistant to all treatment. If this happens, it’s important to weigh the possible limited benefits of a new treatment against the possible downsides, including treatment side effects. Everyone has their own way of looking at this.
This is likely to be the hardest part of your battle with cancer – when you have been through many medical treatments and nothing’s working anymore. Your doctor may offer you new options, but at some point you may need to consider that treatment is not likely to improve your health or change your outcome or survival.
If you want to continue to get treatment for as long as you can, you need to think about the odds of treatment having any benefit and how this compares to the possible risks and side effects. In many cases, your doctor can estimate how likely it is the cancer will respond to treatment you are considering. For instance, the doctor may say that more treatment might have about a 1 in 100 chance of working. Some people are still tempted to try this. But it is important to think about and understand your reasons for choosing this plan.
No matter what you decide to do, it is important that you feel as good as you can. Make sure you are asking for and getting treatment for any symptoms you might have, such as nausea or pain. This type of treatment is called palliative care.
Palliative care helps relieve symptoms, but is not expected to cure the disease. It can be given along with cancer treatment, or can even be cancer treatment. The difference is its purpose – the main goal is to improve the quality of your life, or help you feel as good as you can for as long as you can. Sometimes this means using drugs to help with symptoms like pain or nausea. Sometimes, though, the treatments used to control your symptoms are the same as those used to treat cancer. For instance, radiation might be used to help relieve bone pain caused by cancer that has spread to the bones. But this is not the same as treatment to try to cure the cancer.
At some point, you may benefit from hospice care. This is special care that treats the person rather than the disease; it focuses on quality rather than length of life. Most of the time, it is given at home. Your cancer may be causing problems that need to be managed, and hospice focuses on your comfort. You should know that while getting hospice care often means the end of treatments such as chemo and radiation, it doesn’t mean you can’t have treatment for the problems caused by your cancer or other health conditions. In hospice, the focus of your care is on living life as fully as possible and feeling as well as you can at this difficult time. You can learn more about hospice in our document called Hospice Care.
Staying hopeful is important, too. Your hope for a cure may not be as bright, but there is still hope for good times with family and friends – times that are filled with happiness and meaning. Pausing at this time in your cancer treatment gives you a chance to refocus on the most important things in your life. Now is the time to do some things you’ve always wanted to do and to stop doing the things you no longer want to do. Though the cancer may be beyond your control, there are still choices you can make.
What’s new in thyroid cancer research and treatment?
Important research into thyroid cancer is being done right now in many university hospitals, medical centers, and other institutions around the country. Each year, scientists find out more about what causes the disease, how to prevent it, and how to improve treatment. In past years, for example, evidence has grown showing the benefits of combining surgery with radioactive iodine therapy and thyroid hormone therapy. The results include higher cure rates, lower recurrence rates, and longer survival.
The discovery of the genetic causes of familial (inherited) medullary thyroid cancer now makes it possible to identify family members carrying the abnormal RET gene and to remove the thyroid to prevent cancer from developing there.
Understanding the abnormal genes that cause sporadic (not inherited) thyroid cancer may eventually lead to better treatments as well. In fact, treatments that target some of these gene changes are already being developed (see below).
Most thyroid cancers can be treated successfully. But advanced cancers can be hard to treat, especially if they do not respond to radioactive iodine (RAI) therapy. Doctors and researchers are looking for new ways to treat thyroid cancer that are more effective and lead to fewer side effects.
Surgery is an effective treatment for most thyroid cancers, and it can usually be done without causing major side effects, especially when done by experienced surgeons.
Some people who have thyroid surgery are bothered by the scar it leaves on the neck. Newer approaches to surgery may help with this. For example, in endoscopic surgery, the surgeon operates on the thyroid by inserting, long, thin instruments through small incisions in the neck instead of making one larger incision.
In an even newer approach, the surgeon sits at a control panel and maneuvers robotic arms to do the surgery through an incision under the arm, so there is no scar in the neck. These approaches are much more likely to be used for thyroid conditions other than cancer at this time, but some doctors are now looking to see if they can be used for thyroid cancers as well.
Radioactive iodine (RAI) therapy
Doctors are looking for better ways to see which cancers are likely to come back after surgery. Patients with these cancers may be helped by getting RAI therapy after surgery. Recent studies have shown that patients with very low thyroglobulin levels 3 months after surgery have a very low risk of recurrence even without RAI. More research in this area is still needed.
Researchers are also looking for ways to make RAI effective against more thyroid cancers. For example, in some thyroid cancers, the cells have changes in the BRAF gene, which may make them less likely to respond to RAI therapy. Researchers are studying whether new drugs that target the BRAF pathway can be used to make thyroid cancer cells more likely to take up radioactive iodine. These types of drugs might be useful for people who have advanced cancer that is no longer responding to RAI therapy.
Some studies are testing the value of chemotherapy drugs such as paclitaxel (Taxol®) and other drugs, as well as combined chemotherapy and radiation in treating anaplastic thyroid cancer.
In general, thyroid cancers do not respond well to chemotherapy. But exciting data are emerging about some newer targeted drugs. Unlike standard chemotherapy drugs, which work by attacking rapidly growing cells (including cancer cells), these drugs attack specific targets on cancer cells. Targeted drugs may work in some cases when standard chemotherapy drugs do not, and they often have different (and less severe) side effects.
Tyrosine kinase inhibitors: A class of targeted drugs known as tyrosine kinase inhibitors (TKIs) may help treat thyroid cancer cells with mutations in certain genes, such as BRAF and RET/PTC. Many of these drugs also affect tumor blood vessel growth (see below).
In many papillary thyroid cancers, the cells have changes in the BRAF gene, which helps them grow. Drugs that target cells with BRAF gene changes, such as vemurafenib (Zelboraf®), dabrafenib, and selumetinib, are now being studied in thyroid cancers with this gene change.
Other TKIs that have shown early promise against thyroid cancer in clinical trials include sorafenib (Nexavar®), sunitinib (Sutent®), pazopanib (Votrient®), cabozantinib (Cometriq), motesanib (AMG 706), axitinib (Inlyta®), and vandetanib (Caprelsa®).
Vandetanib and cabozantinib are both targeted drugs shown to be helpful in the treatment of medullary thyroid cancer (MTC) in clinical trials, and are now approved for use against advanced forms of the disease. Some other TKIs, such as sunitinib, sorafenib, and pazopanib, are already approved to treat other types of cancer, and might be useful against MTC and differentiated thyroid cancers if other treatments are no longer working.
Anti-angiogenesis drugs: As tumors grow, they need a larger blood supply to get enough nutrients. They get it by causing new blood vessels to form (a process called angiogenesis). Anti-angiogenesis drugs work by disrupting these new blood vessels. Some of the TKIs listed above, such as axitinib, motesanib, sunitinib, sorafenib, pazopanib, and cabozantinib, have anti-angiogenic properties.
Other anti-angiogenesis drugs being studied for use against thyroid cancer include bevacizumab (Avastin®), lenalidomide (Revlimid®), and lenvatinib.