Thyroid cancer refers to the growth of abnormal (malignant or cancerous) cells in the thyroid gland. The thyroid is a butterfly-shaped gland located in the front of your neck. Although the hormones produced by the thyroid gland affect many organs of the body, its main function is to control the body's metabolism (how fast sources of energy are used). It also helps control body temperature and the level of calcium in the blood. Cancer of the thyroid can be one of four types.
- Papillary carcinoma is the most common thyroid cancer. It usually grows very slowly and is associated with a very high cure rate. Papillary carcinoma is typically found in women of childbearing age. However, it can occur in men and other age groups.
- Follicular carcinoma is the second most common type of thyroid cancer. It typically grows slowly and is usually cured when diagnosed early.
- Medullary carcinoma is cancer of the thyroid cells that make a hormone to control the level of calcium in the blood. This type of cancer also tends to grow slowly, but can be difficult to treat once it spreads. The tendency to develop medullary carcinoma can be inherited.
- Anaplastic carcinoma is also known as giant and spindle cell cancer. It is uncommon, tends to occur in older people and spreads quickly.
Your healthcare provider will look for spread of the thyroid cancer to other areas of the body. This process is called “staging.” Metastatic thyroid cancer is cancer that started in the thyroid and has spread to other organs. In order to decide what type of surgical and non-surgical treatment is ideal for a specific cancer, your healthcare provider will need the following clinical information.
- What does the cancer look like under the microscope?
- Does the thyroid cancer invade outside the thyroid gland or is it limited to the gland itself?
- How large is the primary cancer in the thyroid?
- Has the cancer spread to lymph glands or anywhere else in the body?
Radiation therapy involves the use of various forms of radiation, or high-energy x-ray beams, to kill cancer cells in a specific area of the body. Radiation therapy can be used:
- Before surgery to make a tumor smaller
- To cure a cancer that cannot be removed by surgery
- After surgery to prevent a cancer from returning
- As an alternative to surgery
- To decrease symptoms that are related to a tumor or aggressive cancer
- With chemotherapy
Radiation therapy can be given in various ways, depending on what type of cancer you have and where it is located in your body.
- Radiation therapy to treat thyroid cancer is usually given externally by a machine that is located outside the body. The x-ray beams can kill the cancer cells and shrink a tumor or even make it disappear.
- The x-ray beams must pass through normal tissue on their way to the cancer and out of the body. The radiation that passes through normal organs can cause damage.
- Radiation oncologists plan treatments to minimize exposure to normal organs.
- The treatments must be given daily over several weeks because normal tissues don't tolerate a large dosage given at one time.
Some types of radiation therapy include:
- Three-dimensional (3D) conformal radiation, which uses a beam that goes straight through the body. The patient's position is changed so this beam comes through from two or three different angles. The approach is planned to allow the maximum exposure of radiation to the tumor.
- Intensity-modulated radiation therapy (IMRT) uses hundreds of angles to accomplish the same task. It is far more expensive and is used when many angles are necessary. This approach helps to spare an important organ that is not affected by the cancer. In IMRT the intensity of the beam is varied to conform to the shape of the tumor. The aim is to limit damage to surrounding healthy tissues, while effectively treating the cancer. IMRT is a valuable technique for treating a small percentage of cancerous tumors, but adds little value in the treatment of others. IMRT may not be covered by your health plan unless certain criteria are met.
- Radiation can also be given internally by placing special radioactive source near a tumor (called brachytherapy), orally in the form of a pill or capsule that is swallowed or an infusion of a radioactive substance into a vein.
The decision to administer radiation therapy will depend on the individual circumstances.
Thyroid cancer can develop at any age, but it is most common in women between forty and fifty years of age and men between sixty and seventy years of age. The risk factors for cancer of the thyroid include:
- Radiation exposure (such as from previous radiation treatment or nuclear accidents)
- Radiation therapy to the neck area (usually as a child)
- A low iodine diet
- A chronic thyroid goiter
- Hereditary conditions
- A family history of thyroid cancer
There are no known ways to prevent thyroid cancer. Being aware of your risk factors can result in the cancer being diagnosed and treated sooner, which improves your prognosis.
Often thyroid cancers do not cause symptoms and are discovered during periodic health exam. When symptoms do occur, they may include:
- Swallowing difficulty
- Enlarged thyroid gland
- Lump on thyroid gland
- Changes or hoarseness in voice
- Swelling of the neck
Contact your healthcare provider if you have any of the above symptoms. He or she will review your symptoms and perform a physical examination. They may also recommend one of the following tests:
- Blood tests to check your calcitonin and thyroid hormone levels
- A laryngoscopy, an examination of your throat using a special instrument
- Removal of tissue from the thyroid for examination under a microscope (biopsy)
- A scan of your thyroid gland
- An ultrasound of your thyroid gland
Treatments for thyroid cancer are either local (only affects the area of the cancer) or systemic (affects all areas of the body). Local treatments include:
- Surgery to remove the cancer (thyroidectomy, or removal of the thyroid)
- Radiation to kill the cancer
Systemic treatments include:
- Chemotherapy to kill the cancer cells
- Targeted, or biologic, therapy to interfere with the changes in cells that help the cancer grow
- Internal radiation or radioactive iodine therapy, which is a solution given by mouth and absorbed by certain types of cancerous tissue
All three treatments target and kill cancer cells.
Treatment for thyroid cancer may involve a combination of local and systemic treatments, especially if the cancer has traveled to other parts of your body.
- If the cancer is only in the thyroid, surgery is usually the primary treatment.
- Chemotherapy is usually used to treat thyroid cancer that has spread.
- Oral targeted therapy has been approved for medullary thyroid cancer. Targeted therapy for other types of thyroid cancer also appears promising.
- Radioactive iodine therapy may be recommended after surgery for thyroid cancer that has a high chance of spreading or growing back. It may also be used for some thyroid cancers that have spread outside the thyroid.
- Radiation and chemotherapy are usually given in a clinic or hospital by specially trained medical personnel.
- In some cases, you may be able to receive chemo at home with the help of specially trained nurses.
After treatment, you will need to take a thyroid medication for the rest of your life.
To get a full range of opinions and perspectives, and depending of the specific clinical aspects of your case, you may want to consider input from a variety of doctors. This includes:
- Your primary care physician
- A medical oncologist (a doctor who specializes in the treatment of cancer)
- A surgeon with experience in thyroid cancer
- A radiation oncologist (a doctor who specializes in treating cancer with radiation therapy)
- A genetic counselor
- An endocrinologist
It is important to remember that the total cost of this care path does not include all possible medications, lab work, or imaging studies; those charges can add up. If your healthcare provider recommends any lab work or imaging studies, you may need to search for their costs separately.
Contact your healthcare provider if you have symptoms of thyroid cancer. Be prepared to discuss your symptoms and how long you've had them.
- Bring a copy of your medical history (past illnesses, surgeries, and hospitalizations).
- Make a list of your medications (including over-the-counter).
- Write down any questions, symptoms or concerns you want to talk about.
- If your healthcare provider prescribes a medication for you, ask for a generic version. If your doctor thinks that a generic version is not right for you, ask for a medication on the lowest available tier of your Prescription Drug List (PDL).
What should I ask my healthcare provider before having radiation therapy?
- How will radiation improve my prognosis?
- What specific precautions do I need to take after receiving radiation therapy?
- What are the possible complications?
- How will I feel after radiation therapy? Will I have to modify my activity?
- What type of radiation will I receive? What symptoms should I report to my healthcare provider before my next appointment?
- Is there a reason you are recommending one form of radiation therapy over another?
- Will I be receiving other treatments along with the radiation therapy?
It is important you understand all home care instructions (including medications and side effects) and follow-up plans. Don't forget to make arrangements for help at home.