Early detection of thyroid cancer significantly improves the possibility of successful treatment. Although thyroid cancer sometimes has no symptoms, many tumors are found in the early stages when patients find lumps or nodules in their throats. Doctors sometimes find lumps or nodules during routine checkups.
No screening tests are recommended for the general population. Some experts suggest that people examine their own necks carefully twice annually. If you notice symptoms, you should see your doctor immediately. Be sure your doctor includes a cancer-related checkup in your annual physical.
People with a family history of familial medullary thyroid carcinoma should have a blood test as early as possible to find out if they have the gene that causes this cancer. If they have the gene, they may want to have the thyroid surgically removed to decrease the risk of thyroid cancer.
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If you have symptoms of thyroid cancer, you should visit your doctor as soon as possible. He or she will examine your neck and throat, feeling for lumps or swelling. Your doctor will also complete a medical history. This involves asking questions about your symptoms, other health problems, and health problems in other members of your family. If anyone in your family has ever had thyroid cancer or parathyroid or adrenal tumors, be sure to tell your doctor.
If your doctor thinks you have a thyroid nodule or nodules, you may have a fine-needle aspiration biopsy. In this procedure, a thin needle is inserted into the nodule. Then cells are withdrawn and examined under a microscope.
This procedure usually is done in the doctor's office. In many cases, no anesthesia is needed. Sometimes, an injection of local anesthetic, similar to what is used in a dentist's office, may be given in the skin over the nodule.
Fine-needle aspirations are safe, and the only complication is bleeding. This is not common, however, unless the patient has a bleeding disorder. Tell your doctor before the test if you have a bleeding disorder.
The needle is inserted into the nodule for about 10 seconds. It usually is inserted in two or three locations on the nodule. If nodules are too small to be felt, an ultrasound image may help guide the needle.
After the cells are removed, they are analyzed under a microscope to see if they are cancerous. Most thyroid nodules are proved by FNAs to be benign (noncancerous).
If the FNA is inconclusive—not showing clearly whether the nodule is cancerous—more testing may be needed.
Imaging tests give doctors a picture of the thyroid. There are several types of tests.
Ultrasound. This test uses sound waves to make images of the body. The healthcare provider holds a small device called a transducer close to the throat. The transducer emits silent high-frequency sound waves that bounce off the thyroid. These bounces create echoes that are analyzed by a computer.
Ultrasound is useful for finding thyroid nodules, guiding a needle for biopsy, and imaging the neck after surgery. When examined by ultrasound, some nodules have suspicious findings that make the diagnosis of cancer more likely.
Radioactive thyroid scan. If a nodule is papillary or follicular cancer, a radioactive thyroid scan may be used after thyroid surgery to determine if cancer remains or has spread to other parts of the body. Medullary thyroid cancer cells don't absorb iodine.
First, you will swallow a small amount of radioactive iodine. The thyroid tissue absorbs the radioactive iodine. Then a special camera is pointed at the body. The camera does not touch the skin. The camera measures the amount of iodine that was absorbed by the body.
Patients may be given an injection of thyroid stimulating hormone before a radioactive thyroid scan to increase their level of the hormone and make a scan more effective.
Computer tomography scan. This diagnostic test uses an X-ray machine and a computer to create detailed pictures of the body, including three-dimensional images. As part of a CT scan, you may be asked to drink contrast dye fluid or have an IV (intravenous) line for injection of contrast dye fluid. Although not commonly used to diagnose thyroid cancer, a CT scan can help find out the size of a tumor or whether the cancer has spread.
Magnetic resonance imaging. This diagnostic test uses magnetic fields and radio waves to create computerized pictures of the body. You may be placed in a tube, which can feel confining to people who have a fear of enclosed spaces. The MRI is noisy while it is operating, and you will probably be given earplugs. You may receive an injection or be asked to swallow contrast dye fluid. Although not commonly used to diagnose thyroid cancer, MRI may be used to determine the size of a tumor or determine if the cancer has spread.
Octreotide scan. This scan, which uses a radioactively tagged hormone, is rarely utilized to determine if medullary thyroid carcinoma has spread.
Positron emission tomography. This test uses a radioactive atom, which is included in liquid glucose (a type of sugar). You will receive an injection of the glucose, which is absorbed by cancer cells. A special camera captures images of the cells.
PET is used to evaluate thyroid cancer that has metastasized and is not responsive to radioactive iodine. It appears to be less useful in evaluating medullary carcinoma.
Blood tests are not used to diagnose thyroid cancer, but they are useful in determining the type of cancer and activity of the thyroid.
Thyroid stimulating hormone is measured to check the activity of the thyroid cancer. Blood calcitonin testing will be done if medullary thyroid carcinoma is suspected.
Thyroglobulin, a protein made by the thyroid, is measured after surgical removal of the thyroid. Its presence may suggest that differentiated thyroid cancer is still present or returning.
If you have medullary thyroid cancer, you will be given a blood test to determine if you carry a gene that sometimes causes this cancer. If the test is positive, your children and parents should be tested to see if they have the gene or thyroid cancer. More than 90 percent of people who have the gene will eventually develop the cancer.
If your child has the gene, the doctor will probably suggest removal of the thyroid. Although children rarely develop cancer before 5 years of age, one type of MTC (known as MEN-2B) can develop in the early months of life. If the thyroid is removed, a person will take daily thyroid medication for the rest of his or her life.
If you are diagnosed with thyroid cancer, your doctor may complete more tests to determine how big the tumor is and whether the cancer has spread to more places in the body. This process of evaluation, called staging, helps healthcare professionals plan your treatment. It also provides information about the expected outcome, or prognosis, of your cancer.
Papillary and follicular thyroid cancer. In papillary and follicular (or differentiated) thyroid cancer, the age at diagnosis is important to staging. The stages go from I to IVC.
Medullary thyroid cancer. The stages go from 0 to IVC.
Anaplastic thyroid cancer is always considered stage IV.
Recurrent thyroid cancer is cancer that returns after the original cancer has been treated. Although it usually comes back in the neck, thyroid cancer can appear in other parts of the body. When thyroid cancer returns, it is classified as the same stage as the original cancer.
Last reviewed on 6/4/09
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