How common is thyroid cancer?

Thyroid cancer is a disease in which thyroid cells become abnormal, grow uncontrollably, and form a cancerous tumor. If left untreated, thyroid cancer can spread and cause harm to other parts of the body through a process called metastasis. There are four major types of thyroid cancer.

The four major types are: papillary, follicular, medullary, and anaplastic. The different types of look different under a microscope and grow at different rates. Papillary cancer. This type of thyroid cancer develops in the cells that produce thyroid hormones containing iodine. Papillary cancer grows very slowly and contains cells that are similar to healthy thyroid cells. Papillary cancers account for about 60 to 80 percent of all thyroid cancers. Follicular cancer.

This type of cancer also develops in thyroid cells that produce iodine-containing hormones. About 10 to 30 percent of thyroid cancers are follicular cancers. Medullary cancer. Medullary cancer is more difficult to control than papillary and follicular thyroid cancers. It is more difficult to control because the cancer cells tend to spread to other parts of the body. The cells involved in medullary cancers produce calcitonin. Calcitonin does not contain iodine.

About 5 to 7 percent of all thyroid cancers are medullary cancers. What is the Thyroid Gland? The thyroid gland is a type of endocrine gland, that secretes hormones (thyroglobulin) necessary for growth and proper metabolism. The thyroid gland also maintains blood calcium balance within a narrow range. The thyroid gland is necessary for life. It is located in the lower part of the neck. What Causes Thyroid Cancer? The exact cause of thyroid cancer is unknown. However, several factors have been noted to increase the risk of developing thyroid cancer. Some of the noted factors of developing thyroid cancer are: · are an enlarged thyroid gland · the presence of nodules on the thyroid · radiation exposure · family history of thyroid cancer · chronic infections · inflammation of the thyroid

What are the Signs and Symptoms of Thyroid Cancer?

In early stages of thyroid cancer there are often no signs or symptoms, although there are some things to look out for. A risk factor is something that increases your chance of getting a disease, but many people with risk factors for thyroid cancer never develop the disease. Can Thyroid Cancer be Prevented? Unfortunately, since most people with thyroid cancer have no known risk factors, it is very difficult to prevent most cases of thyroid cancer. Can Thyroid Cancer be treated? Yes. The treatment for thyroid cancer depends on the type and stage of disease, as well as the age and overall health of the patient. Types of treatment used are: surgery (removal of the diseased part of the thyroid), chemotherapy, radioactive iodine therapy and/or hormone therapy.

Treatment Surgery is the main treatment for most types of thyroid cancer, but other therapies may vary, depending on the type of thyroid cancer you have.

Papillary and follicular thyroid cancers

The best type of surgery for follicular and papillary thyroid cancers was once a matter of debate. Now most experts agree that the optimal treatment is near-total thyroidectomy - an operation that removes practically the entire thyroid with the exception of small rims of tissue around the parathyroid glands to reduce the risk of parathyroid damage. If you have enlarged lymph nodes as a result of thyroid cancer, your operation may be extended to remove the affected lymph nodes. In some cases, this may mean exploring and removing enlarged lymph nodes on both sides of your neck. Cancer is less likely to return or spread after thyroidectomy than after less complete operations, and in experienced hands, the risks of the surgery are low. Surgical treatment of follicular cancer is more complicated than that of papillary cancer because follicular cancer usually can't be diagnosed until the affected tissue is examined.

Sometimes this occurs during surgery using a technique called frozen section, which takes less than 10 minutes to complete and which is performed while you're still anesthetized. When this procedure isn't available, surgeons are likely to remove the lobe of the thyroid that contains the nodule (lobectomy) and send it to a pathologist, who examines it under a microscope. If the nodule is malignant, the next step is near-total thyroidectomy. After any type of surgery for thyroid cancer, you'll need to take the thyroid hormone medication levothyroxine (Levothroid, Synthroid) for life. This has two benefits: It supplies the missing hormone your thyroid would normally produce, and it suppresses the pituitary's production of TSH, which signals your thyroid to manufacture hormones. High TSH levels could conceivably stimulate any remaining cancer cells to grow. You'll likely have blood tests to check your thyroid hormone levels every few months until your doctor finds the proper dosage for you. Too much hormone can cause unintended weight loss, palpitations, tremors, osteoporosis and frequent bowel movements. Too little may lead to weight gain, sensitivity to cold, and dry skin and hair. Other treatments for papillary and follicular cancers include:

· Radioactive iodine (radioiodine) therapy.

This therapy may be used in treating thyroid cancer for two reasons. One is to destroy any normal tissue that remains after near-total thyroidectomy. A procedure called remnant ablation uses a moderate dose of iodine to destroy the rims of tissue that have been left after surgery to protect the parathyroids. Radioiodine therapy is a standard treatment for follicular cancer and may sometimes be used in people with papillary cancer. Radioiodine therapy may also be used to destroy any cancer that has spread beyond the thyroid gland. In this treatment, you take a capsule containing iodine 131, usually at a higher dose than is used for remnant ablation. Because iodine 131 is taken up primarily by thyroid tissue - including thyroid cancer cells - other parts of your body aren't affected. You must have any remaining thyroid tissue removed before you can undergo radioiodine therapy. That's because normal thyroid tissue absorbs more iodine than do cancer cells, and its presence would make the treatment less effective. In addition, you need high blood levels of TSH in order for cancer cells to take up radioactive iodine. For that reason, you normally must discontinue taking thyroid hormones for up to two weeks before therapy. An alternative approach is to use a synthetic version of a hormone that artificially elevates blood levels of TSH. You may have a sore throat, nausea and vomiting immediately after radioiodine treatment. You may also have a dry mouth or pain in your cheeks and neck because your salivary glands may absorb some of the radioactive iodine. And because iodine 131 can affect the thyroid gland of a developing fetus or infant, you shouldn't have radioiodine therapy if you're pregnant or breastfeeding.

· External beam radiation.

Like radioiodine therapy, external beam radiation uses radiation to destroy cancer cells. But in this case, the rays come from a source outside your body - a high-energy X-ray machine called a linear accelerator. The cancer cells are targeted with a high dose of radiation for a few minutes at a time, usually five days a week, over the course of six to eight weeks. The goal is to destroy the cancer cells while minimizing damage to healthy tissue. You're likely to feel very tired later in the course of treatment, and your skin may become red and tender in the treated area, as if you had bad sunburn. You may also feel hoarse or have trouble swallowing. Follow-up care after treatment for follicular or papillary thyroid cancer is important. Thyroid cancer can recur as many as 20 or 30 years after the original diagnosis, although if you've remained cancer-free for five years, the recurrence rate is low. Still, you'll have periodic blood tests to monitor your level of thyroglobulin, a protein that stores thyroid hormone. Elevated levels of this hormone could indicate that the cancer has returned. You may also have imaging tests or other tests that help your doctor check for a recurrence of cancer.

Medullary thyroid cancer

This type of cancer usually occurs in both lobes of the thyroid gland and often involves multiple tumors. For that reason, the best treatment is total thyroidectomy. And because medullary cancer has often spread to the lymph nodes by the time it's diagnosed, you may have lymph nodes removed (dissection) on both sides of your neck. When the cancer hasn't metastasized, the outlook after surgery is excellent. If the cancer has spread to other organs, treatment depends on several factors, including the size of the tumor, how quickly it's growing, and the extent of the spread. For example, your doctor might choose not to surgically remove a small tumor in the liver, lung or bone. Such tumors sometimes grow slowly for years without causing any symptoms. Large or rapidly growing tumors, on the other hand, may need surgery or other treatment.

In that case, you and your doctor will work together to decide on the best type of therapy. Radioiodine treatments aren't an option for people with medullary cancer because thyroid C cells don't absorb iodine, but you may receive external radiation or chemotherapy, which uses drugs to kill cancer cells. Not every person with medullary thyroid cancer responds to chemotherapy, but in some cases a combination of cancer drugs may shrink tumors or slow their growth. The encouraging news is that although medullary thyroid cancers can be aggressive, some grow slowly - sometimes for years - without causing major symptoms. Follow-up care includes regular physical examinations and blood tests to check your calcitonin and CEA levels. Anaplastic thyroid cancer The most aggressive and fastest growing type of thyroid cancer, anaplastic cancer often can't be helped by surgery by the time it's diagnosed. Radiation or chemotherapy may shrink tumors slightly and make you more comfortable.

But because no treatment can eliminate advanced anaplastic cancer, you may want to consider participating in a clinical trial. This is a study that tests new forms of therapy - typically new drugs or surgical procedures, or novel treatments such as gene therapy. If the therapy proves to be safer or more effective than current treatments, it becomes the new standard of care. But treatments used in clinical trials haven't been shown to be effective. They may have serious or unexpected side effects, and there's no guarantee you'll benefit from them. On the other hand, cancer clinical trials are closely monitored to ensure that they're conducted as safely as possible. And they offer access to treatments that wouldn't otherwise be available to you.