Cancer Treatment & Information

What are the symptoms of Thyroid Cancer?

Early thyroid cancer often does not cause symptoms. But as the cancer grows, symptoms may include:

• A lump, or nodule, in the front of the neck near the Adam’s apple;
• Hoarseness or difficulty speaking in a normal voice;
• Swollen lymph nodes, especially in the neck;
• Difficulty swallowing or breathing;
• Pain in the throat or neck.

These symptoms are not sure signs of thyroid cancer. An infection, a benign goiter, or another problem also could cause these symptoms. Anyone with these symptoms should see a doctor as soon as possible. Only a doctor can diagnose and treat the problem.

How is Thyroid Cancer diagnosed?

Although it’s possible that you may see or feel a lump (nodule) in your thyroid yourself — usually just to the lower right or left of your Adam’s apple — it’s more likely that your doctor will discover a lump during a routine medical exam. You’re usually asked to swallow while your doctor examines your thyroid because the thyroid moves up and down during swallowing, making nodules easier to feel.

Sometimes a thyroid nodule is detected as an incidental finding when you have an imaging test to evaluate another condition in your head or neck. Nodules detected this way are usually too small to be found during a physical exam. To aid in diagnosis, you may have one or more of the following tests:

• Ultrasound scan. This imaging technique uses high-frequency sound waves to outline the neck anatomy and detect abnormal growths. While very good at identifying whether a growth or nodule is present, ultrasound scans can’t tell for sure whether it’s malignant or benign. Ultrasound is safe, with virtually no complications associated with its use.
• Fine-needle aspiration (FNA) biopsy. This test is generally considered the most sensitive for distinguishing between benign and malignant thyroid nodules. During the procedure, your doctor places a thin needle through your skin and into a nodule and removes a sample of cells. Several passes are usually needed to obtain tissue from different parts of the nodule. If you have more than one nodule, your doctor is likely to take samples from as many as possible. Often, your doctor will use ultrasound to help guide the placement of the needle. The samples are then sent to a laboratory and analyzed under a microscope. Only a small percentage of biopsied nodules are malignant. This diagnosis is based on the characteristics of individual cells and patterns in clusters of cells that are different from normal thyroid tissue. In some cases, a pathologist can determine specific types of cancer from an FNA biopsy sample.
• Blood tests. If your doctor suspects medullary cancer, you may have tests that check for high levels of calcitonin in your blood. Other tests can provide information about the function of your thyroid gland. For example, you may have a test that measures thyroid-stimulating hormone (TSH), a hormone made by the pituitary gland that regulates thyroid hormones.

Staging tests - If you receive a diagnosis of thyroid cancer, you’re likely to have tests to help determine whether the cancer has spread (metastasized) — a process known as staging. The stage of cancer helps your doctor determine the best course of treatment and the outlook for your recovery. The staging tests you have may vary, depending on the type of thyroid cancer.

Tests such as ultrasonography, computerized tomography (CT) and magnetic resonance imaging (MRI) may help your doctor to see whether the cancer has spread to the lymph nodes or other areas of your neck. Sometimes you may have an octreotide scan — a test that uses a radioactively tagged hormone to check for the spread of medullary cancer.

Screening tests - If you have medullary cancer, consider having DNA testing, which checks a blood sample for the known genetic defects that cause familial and MEN-associated medullary thyroid cancer. A genetic counselor can help determine what a positive or negative test result may mean for your family.

If you have medullary thyroid cancer but don’t test positive for the RET gene, it’s still important that your close family members have their calcitonin levels tested. This is generally done using a calcium infusion test. Although the calcitonin level of healthy people rises slightly after an injection of calcium, it’s much higher in people with medullary thyroid cancer.

The calcium infusion test usually takes between 15 and 20 minutes and is done on an outpatient basis. You’ll have a small amount of blood drawn before the injection of calcium and again at two, five, 10 and 15 minutes after the injection.

What is Thyroid Cancer?

Thyroid cancer is a disease in which cancer (malignant) cells are found in the tissues of the thyroid gland. The thyroid gland is at the base of the throat. It has two lobes, one on the right side and one on the left. The thyroid gland makes important hormones that help the body function normally.

Certain factors may increase the risk of developing thyroid cancer.

• Thyroid cancer occurs more often in people between the ages of 25 and 65 years.
• People who have been exposed to radiation or received radiation treatments to the head and neck during infancy or childhood have a greater chance of developing thyroid cancer. The cancer may occur as early as 5 years after exposure or may occur 20 or more years later.
• People who have had goiter (enlarged thyroid) or a family history of thyroid disease have an increased risk of developing thyroid cancer.
• Thyroid cancer is more common in women than in men.
• Asian people have an increased risk of developing thyroid cancer.

A doctor should be seen if there is a lump or swelling in the front of the neck or in other parts of the neck.

If there are symptoms, a doctor will feel the patient’s thyroid and check for lumps in the neck. The doctor may order blood tests and special scans to see whether a lump in the thyroid is making too many hormones. The doctor may want to take a small amount of tissue from the thyroid. This is called a biopsy. To do this, a small needle is inserted into the thyroid at the base of the throat and some tissue is drawn out. The tissue is then looked at under a microscope to see whether it contains cancer.

There are four main types of thyroid cancer (based on how the cancer cells look under a microscope):

1. papillary
2. follicular
3. medullary
4. anaplastic

Some types of thyroid cancer grow faster than others. The chance of recovery (prognosis) depends on the type of thyroid cancer, whether it is in the thyroid only or has spread to other parts of the body (stage), and the patient’s age and overall health. The prognosis is better for patients younger than 40 years who have cancer that has not spread beyond the thyroid.

The genes in our cells carry the hereditary information from our parents. An abnormal gene has been found in patients with some forms of thyroid cancer. If medullary thyroid cancer is found, the patient may have been born with a certain abnormal gene which may have led to the cancer. Family members may have also inherited this abnormal gene. Tests have been developed to determine who has the genetic defect long before any cancer appears. It is important that the patient and his or her family members (children, grandchildren, parents, brothers, sisters, nieces and nephews) see a doctor about tests that will show if the abnormal gene is present. These tests are confidential and can help the doctor help patients. Family members, including young children, who don’t have cancer, but do have this abnormal gene, may reduce the chance of developing medullary thyroid cancer by having surgery to safely remove the thyroid gland (thyroidectomy).

What causes Thyroid Cancer?

No one knows the exact causes of thyroid cancer. Doctors can seldom explain why one person gets this disease and another does not. However, it is clear that thyroid cancer is not contagious. No one can “catch” 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 anything that increases a person’s chance of developing a disease. The following risk factors are associated with an increased chance of developing 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 small doses of radiation. Their benefits nearly always outweigh their risks. However, repeated exposure could be harmful, so it is a good idea for people to talk with their 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 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). 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 for thyroid diseases. People who are concerned about their exposure to radiation from medical treatments or radioactive fallout may wish to ask the Cancer Information Service at 1-800-4-CANCER about additional sources of information.

Family history. Medullary thyroid cancer can be caused by a change, or alteration, in a gene called RET. The altered RET gene can be passed from parent to child. Nearly everyone with the altered RET gene will develop medullary thyroid cancer. A blood test can detect an altered RET gene. If the abnormal gene is found in a person with medullary thyroid cancer, the doctor may suggest that family members be tested. For those found to carry the altered RET gene, the doctor may recommend frequent lab tests or surgery to remove the thyroid before cancer develops. When medullary thyroid cancer runs in a family, the doctor may call this “familial medullary thyroid cancer” or “multiple endocrine neoplasia (MEN) syndrome.” People with the MEN syndrome tend to develop certain other types of cancer.A small number of people with a family history of goiter or certain precancerous polyps in the colon are at risk for developing papillary thyroid cancer.

Being female. In the United States, women are two to three times more likely than men to develop thyroid cancer.

Age. Most patients with thyroid cancer are more than 40 years old. People with anaplastic thyroid cancer are usually more than 65 years old.

Race. In the United States, white people are more likely than African Americans to be diagnosed with thyroid cancer.

Not enough iodine in the diet. The thyroid needs iodine to make thyroid hormone. In the United States, iodine is added to salt to protect people from thyroid problems. Thyroid cancer seems to be less common in the United States than in countries where iodine is not part of the diet.

Most people who have known risk factors do not get thyroid cancer. On the other hand, many who do get the disease have none of these risk factors. People who think they may be at risk for thyroid cancer should discuss this concern with their doctor. The doctor may suggest ways to reduce the risk and can plan an appropriate schedule for checkups.