What is the thyroid gland and what does it do?
Your thyroid is a gland located at the base of your neck, just below your Adam’s apple. It is shaped like a butterfly – each wing, or lobe of your thyroid lies on either side of your windpipe.

The purpose of your thyroid gland is to make, store, and release thyroid hormones into your blood. These hormones, which are also referred to as T3 and T4, affect almost every cell in your body, and help control your body’s functions. If you have too little thyroid hormone in your blood, your body slows down. This condition is called hypothyroidism. If you have too much thyroid hormone in your blood, your body speeds up. This condition is called hyperthyroidism.

The amount of thyroid hormone made by your thyroid gland is adjusted by a gland in the brain call the pituitary. Another part of your brain, the hypothalamus, helps the pituitary.

The hypothalamus sends information to the pituitary gland
The pituitary in turn controls the thyroid gland

The thyroid gland, pituitary gland, and hypothalamus all work together to control the amount of thyroid hormone in your body. With the pituitary controlling most of the action, these organs work similarly to the way a thermostat controls temperature in a room.

For example, just as the thermometer in a thermostat senses the temperature of a room, your pituitary gland constantly senses the amount of thyroid hormone in your blood. If there is not enough thyroid hormone, your pituitary senses the need to “turn on the heat”. It does this by releasing more thyroid-stimulating hormone (or TSH), which signals your thyroid to make more thyroid hormone. Your thyroid gland then makes and releases the hormone directly into your bloodstream.

Your pituitary gland then senses that there is just the right amount of thyroid hormone in your body. With your thyroid hormone levels now restored to a normal level, your pituitary slows its production of TSH back down to normal.

What is thyroid cancer?
Thyroid cancer is a cancerous tumor or growth located within the thyroid gland. Thyroid cancer is uncommon, accounting for only about 1 out of every 100 cancers in the United States. Of these thyroid cancers, 65% to 80% are diagnosed as papillary thyroid cancer, 10% to 15% are follicular, 5% to 10% are medullary, and 3% to 5% are anaplastic. If you or someone you know has been diagnosed with thyroid cancer, you will be glad to know that the outlook with treatment is excellent – most thyroid cancers can be totally removed with surgery.

However, this type of cancer can sometimes come back or spread to other parts of the body, even many years later. For this reason, doctors recommend that people who have had thyroid cancer receive routine checkups for the rest of their life to make sure their cancer hasn’t recurred or spread. In particular, many doctors feel that testing within the first 5 to 10 years after surgery is critical.

What causes thyroid cancer?
Thyroid cancer is more likely to occur in people who have undergone radiation therapy of the head, neck, or chest during childhood. Radiation was commonly used before 1960 to shrink enlarged tonsils or adenoids, to treat various skin problems (such as acne), and to reduce an enlarged thymus gland (an organ inside the chest) in infants. Radiation that is used in diagnostic x-rays (for example, x-rays used by dentists) is not connected with thyroid cancer.

Thyroid cancer is also more likely to occur if you have a family member who has had thyroid cancer. However, thyroid cancer can occur in anyone.

How is thyroid cancer diagnosed?
Thyroid cancer is often discovered by patients themselves. You may see or feel a lump or nodule on the front of your neck, or your doctor may notice a nodule during a routine physical examination.

Fortunately, most of the time, nodules are benign, which means they are not life-threatening. Only about 1 out of every 20 nodules ever turns out to be cancerous. In fact, benign thyroid nodules are extremely common – it is estimated that they may be present in more than half of the people in the United States. However, most nodules are so small that they are never discovered by the patient or doctor. Your doctor can usually make a diagnosis of a thyroid nodule with little risk or discomfort to you. He or she will carefully examine your thyroid gland for other nodules or for a goiter (enlarged thyroid gland) by pressing on it.

Once a thyroid lump or nodule is discovered, your doctor will probably ask how you have been feeling and if you are experiencing any symptoms possibly caused by thyroid nodules.

After completing the physical examination and taking your medical history, the doctor will likely do more tests, including:

Blood tests (to measure the level of thyroid hormones)
Thyroid imaging tests or scans (to take a picture of your entire thyroid gland)
Thyroid biopsy (to see if the lump contains cancer cells)

What is a biopsy and why is it done?
Your specialist (endocrinologist) can use a fine needle aspiration biopsy (FNAB) to learn whether a thyroid nodule is benign or cancerous. With this test, the skin may be numbed and a small needle is inserted into the thyroid nodule in order to remove samples of tissue or fluid, which are then analyzed in a lab. The test is fast, safe, and usually causes little discomfort.

What if the biopsy shows that my nodule is cancerous?
Even if it turns out to be cancerous, the thyroid nodule in most cases will grow very slowly. Plus, once a patient has treatment, the outlook is excellent – most thyroid cancers can be totally removed with surgery and follow-up therapy. This surgery, called thyroidectomy, removes part or all of the thyroid gland. Thyroid surgery is commonly followed by treatment with radioactive iodine to destroy “leftover” normal thyroid cells, as well as thyroid cancer cells.

Once your thyroid gland has been removed, your doctor will most likely have you start taking thyroid hormone to replace the hormone your thyroid gland used to make. Another reason to take thyroid hormone after thyroidectomy is that TSH (made by the pituitary gland) may cause thyroid cancers to grow. But taking thyroid hormone tablets sends a signal to the pituitary gland to make less TSH. So taking the thyroid hormone tablets helps in two ways:

It replaces the thyroid hormone that your body used to make on its own, so that you will not become hypothyroid.
It tells the pituitary to make less TSH, so that if thyroid cancer cells are present, they will not grow so well.

Once my surgery is over, is my cancer gone forever?
Sometimes thyroid cancer can come back or spread to other parts of the body – even many years after surgery. That is why your doctor needs you to come in for regular checkups especially in the first 5 to 10 years after your surgery.

If you have had surgery to remove all or part of your thyroid gland because of thyroid cancer, your doctor will use two primary tests to check if the cancer has come back or spread to other parts of your body. One is a blood test (called a thyroglobulin test) and the other is called a whole body scan (or WBS). Your doctor may decide to test you with both tests or sometimes just with the blood test.

Thyroglobulin Blood Test
A thyroglobulin test is a blood test that measures the amount of thyroglobulin, a protein that stores thyroid hormone, in your blood. Thyroid cells are the only cells in your body that make thyroglobulin. So if thyroglobulin shows up in your blood test, then you know that thyroid cells or thyroid cancer cells are present somewhere in your body.

Whole body scan
Another test that checks for the return or spread of the cancer is called a whole body scan, or WBS. In this test, you will be asked to take a pill or drink with a small, safe amount of radioactivity, called 131I (“eye-one-thirty-one). After you have taken the pill or drink, you will lie down under a large camera that takes an x-ray picture (scan) of your body. If any thyroid cells are present in your body, they will show up as spots on the film.

Will this testing have an impact on my life?
In the past, whenever people were tested for the return or spread of thyroid cancer (especially if they had a whole body scan), they had to stop taking their thyroid medication for 2 to 6 weeks before the test. This allowed their body to produce enough TSH to make the tests as accurate as possible. But it also caused patients to become hypothyroid. Plus, even when the testing was done and they started taking their thyroid medication again, many people continued to feel hypothyroid until the level of thyroid hormone in their bloodstream returned to normal. All in all, some people felt the symptoms of hypothyroidism for up to 10 to 12 weeks.

As previously mentioned, most thyroidectomy patients start taking thyroid hormone after their surgery. It replaces the hormone that the thyroid gland used to make. Taking thyroid hormone prevents you from experiencing hypothyroidism, which can cause a variety of symptoms, such as depression, difficulty in concentrating, tiredness, forgetfulness, dry skin and hair, puffy face and eyes, inability to tolerate the cold, weight gain, constipation, and heavy menstrual periods in women. These symptoms of hypothyroidism vary from patient to patient.

What is Thyrogen^®?
Thyrogen is just like the TSH that the body produces naturally, although it is made in a laboratory. Because Thyrogen is just like TSH, you do not have to stop taking your thyroid hormone therapy or risk going through weeks of feeling bad before being tested. You can keep taking your thyroid hormone therapy. In other words, you will not have to become hypothyroid. This is especially important in the first years after thyroidectomy, since patients must undergo repeated testing for the return or spread of the cancer during this period.

Side effects of taking Thyrogen (thyrotropin alfa for injection) are few and generally mild. Some people experience nausea, headache, weakness, or vomiting after their injection. A few people have experienced itching or rash at the site of the injection. Please see the section entitled ADVERSE REACTIONS in the complete prescribing information. If you experience any side effects or have any questions, contact your doctor.

Why might my doctor prescribe Thyrogen for my tests?
There are four reasons why you and your doctor may decide to use Thyrogen when you have the cancer-detecting tests:

(1) If a previous thyroglobulin blood test performed while you were taking your thyroid hormone therapy did not detect any cancer cells and you doctor wants to confirm this result with a Thyrogen thyroglobulin blood test, which is more accurate.
(2) If you are unwilling to stop taking your thyroid hormone therapy and your doctor believes that Thyrogen use is appropriate.
(3) If, without Thyrogen, your body does not produce enough TSH.
(4) If you have certain medical conditions.

Thyroglobulin tests and whole body scans may be more sensitive (that is, less likely to miss thyroid cells) when you stop taking your thyroid hormone therapy than when you take Thyrogen. For now, you and your doctor may decide that the benefits of not having to go off your thyroid hormone therapy justify using Thyrogen. If your doctor later suspects that your risk for cancer recurrence is high, he or she may test you again while you are not taking your thyroid hormone. Your thyroid hormone therapy must also be stopped if your tests show you need 131I treatment.

How can I get on with my life, knowing that my cancer might come back?
It is scary to find out you have thyroid cancer. But now that you will have surgery to remove the cancer (or you have had the surgery in the past) and you are taking thyroid hormone therapy, your life can just about return to normal. Take good care of yourself by eating well, exercising regularly, and managing stress. Learning relaxation methods, learning to set priorities, and remembering to laugh all help to reduce stress. Take pleasure in doing things that you did before your diagnosis. Most of all, get regular checkups to make sure you remain cancer free. If you find it difficult to have regular checkups for any reason, talk with your doctor or nurse about your concerns.

Remember, you do not have to go through this alone. Talk to family and friends about whatever fears and questions you may have, and consider joining a thyroid cancer support group. At a support group, you will find other people who are willing to share their firsthand experience with thyroid cancer. To find a support group in your area, ask your doctor or nurse, or contact one of the thyroid cancer organizations listed in our links page.

*Copyright 2000 Genzyme Corporation