What Is Thyroid Cancer?
The thyroid gland is located under the Adam's apple in the front part of the neck. In most people, it cannot be seen or felt. It is butterfly shaped, with 2 lobes - the right lobe and the left lobe - joined by a narrow isthmus (see diagram).

The thyroid gland makes a hormone (called thyroid hormone), which is important for many body functions. The production of this hormone depends on iodine, and the thyroid gland absorbs iodine from the blood.

Thyroid hormone regulates a person's metabolism. Too much hormone causes a person to be hyperactive, feel nervous, warm, hungry, and often lose weight. Too little hormone causes a person to slow down, feel tired and gain weight. All this is regulated by the pituitary gland, at the base of the brain, which produces a substance called thyroid stimulating hormone (TSH)

The thyroid gland contains mainly 2 types of cells:

• Thyroid follicle cells actually make and store thyroid hormone. They also make a special thyroid protein called thyroglobulin.
• C cells make another hormone, calcitonin, which helps regulate the body's calcium metabolism.

Different cancers develop from each kind of cell. The differences are important because they determine the seriousness of the cancer and the type of treatment needed.

Many types of tumors can develop in the thyroid gland. Most of these tumors are benign (noncancerous). Others are malignant (cancerous), which means they can spread into nearby tissues and to other parts of the body. Because the thyroid gland is close to the skin, tumors often appear as bumps in the neck. They are called thyroid nodules. Thyroid nodules can develop at any age, but they are most common in adults, occurring in at least half of all people. Often people find these bumps themselves by seeing or feeling them. Most of the time they are never noticed and never cause a problem. Thyroid nodules can be either benign or malignant. Fortunately, most are benign.

Benign Thyroid Tumors
A study out of Framingham, Massachusetts found thyroid nodules in one out of 1000 people undergoing yearly physical examinations. Almost all (90%-95%) of thyroid nodules or tumors are benign. They develop from thyroid follicular cells and can be found in normal-sized thyroid glands and goiters (enlarged thyroid glands). Goiters often develop when a person doesn't have enough iodine in his or her diet. The thyroid may contain 1 nodule or several nodules. A gland with several benign nodules is called a multinodular goiter. Often these nodules are cysts filled with fluid, or they may be "lumps" of stored thyroid hormone called colloid nodules. Colloid nodules have very few cells in them.

Other nodules may have too many cells, but the cells are not cancer cells. This type of nodule includes hyperplastic nodules and adenomas. Sometimes hyperplastic nodules or adenomas make too much thyroid hormone, causing a condition called hyperthyroidism. Symptoms of hyperthyroidism include nervousness, irregular and rapid beating of the heart, excessive sweating, and weight loss. But even these nodules are not cancerous.

Malignant Thyroid Tumors
Only 5% to10% of thyroid nodules are cancerous. There are several types of thyroid cancer. Papillary carcinoma and follicular carcinoma are the most common. Hürthle cell carcinoma is a subtype of follicular carcinoma. Some doctors group these together and call them "differentiated thyroid cancer" or "well-differentiated thyroid cancer." Other types of thyroid cancer, including medullary carcinoma, anaplastic carcinoma, and thyroid lymphoma occur less often.

Malignant Thyroid Tumors - Differentiated Thyroid Cancer
Papillary carcinoma: About 80% of thyroid cancers are papillary carcinomas (also called papillary cancer or papillary adenocarcinoma). Papillary carcinomas develop from the thyroid follicle cells and typically grow very slowly. Usually they occur in only one lobe of the thyroid gland, but about 10% to 20% of the time both lobes are involved. Several different variants (subtypes) of papillary carcinoma can be recognized under the microscope. These include the follicular variant, tall cell variant, columnar cell variant, and diffuse sclerosing variant. Of these variants, the follicular variant of papillary carcinoma is the most common.

The usual form of papillary adenocarcinoma and the follicular variant have the same outlook for survival (prognosis), and treatment is the same for both. The other variants tend to spread more quickly and have a worse prognosis. Even though papillary cancer cells grow slowly, they often spread early to the lymph nodes in the neck. Most of the time, however, this can be successfully treated and is rarely fatal.

Follicular carcinoma: Follicular carcinoma is the next most common type of thyroid cancer. It is also sometimes called follicular cancer or follicular adenocarcinoma. Follicular cancer is much less common than papillary thyroid cancer, making up about 10% of thyroid cancers. It is more common in countries where people don't get enough iodine in their diet. These cancers usually remain in the thyroid gland but can spread to other parts of the body, such as lungs and bone. Unlike papillary carcinoma, follicular carcinomas spread to lymph nodes less often. The prognosis of follicular carcinoma is probably the same or slightly worse than that of papillary carcinoma.

Hürthle cell carcinoma, also known as oxyphil cell carcinoma, is thought to be a subtype of follicular cancer. This type accounts for about 4% of thyroid cancers. It may have a worse prognosis than typical follicular carcinoma because this subtype of follicular cancer, unlike the usual subtype, does not concentrate radioactive iodine well (see below).

Malignant Thyroid Tumors - Other Types
Medullary thyroid carcinoma: Medullary thyroid carcinoma (MTC- about 3% of thyroid cancers ) is the only thyroid cancer that develops from the C cells of the thyroid gland. Sometimes this cancer can spread to lymph nodes, the lungs, or liver even before a thyroid nodule is discovered or a screening test is done. These cancers usually make calcitonin and carcinoembryonic antigen (CEA). Calcitonin, a hormone also produced by normal C cells, helps control the amount of calcium in blood. CEA is a protein produced by certain cancers, such as colorectal cancer and MTC. Both calcitonin and CEA are released into the blood and can be found by blood tests. About 5% of thyroid cancers are medullary. Medullary cancer does not concentrate radioactive iodine and has a worse prognosis.

There are 2 types of MTC. The first type, occurring in 85% of cases, is called sporadic MTC. Sporadic MTC is not inherited; that is, it does not run in families. It occurs mostly in older adults and in only 1 thyroid lobe.

The other type of MTC is inherited and can occur in each generation of a family. When MTC is the only type of cancer found in the family, it is called isolated familial medullary thyroid carcinoma (FMTC). The combination of FMTC and tumors of certain other organs is called type 2 multiple endocrine neoplasia (MEN 2). Type 2 MEN has 2 subtypes, MEN 2a and MEN 2b:

• In MEN 2a, MTC occurs with adrenal gland tumors called pheochromocytomas and with parathyroid gland tumors that cause high blood calcium levels. The adrenal glands are found next to the upper part of each kidney. Most people have 4 parathyroid glands, which are found next to the thyroid.
• In MEN 2b, MTC is associated with pheochromocytoma but not parathyroid gland disease. Instead, MEN 2b includes benign growths of nerve tissues on the tongue and elsewhere called neuromas. In these familial or genetic forms of MTC, the cancers often develop during childhood or early adulthood and can spread early. MTC is most aggressive in the MEN 2b syndrome.

Anaplastic carcinoma: Anaplastic carcinoma is an uncommon (about 2% of all thyroid cancers) form of thyroid cancer. It is believed to develop from an existing papillary or follicular cancer. It is an aggressive cancer that rapidly invades the neck, often spreads to other parts of the body, and is usually fatal. Anaplastic carcinoma is sometimes called undifferentiated thyroid cancer. Both of these names indicate that, under the microscope, they have very little, if any, similarity to normal thyroid tissue. In contrast, the similarity of differentiated thyroid cancer to normal thyroid tissue is easily seen under the microscope.

Thyroid lymphoma: Lymphoma can develop in the thyroid gland but is very uncommon in that location. It does not develop from either thyroid follicular cells or C cells. Rather, lymphomas develop from lymphocytes, the main cell type of the immune system. Most lymphocytes are found in pea-sized collections scattered throughout the body called lymph nodes, and that is where most lymphomas begin. These types of lymphomas are discussed in the American Cancer Society document, "Non-Hodgkin Lymphoma."

Parathyroid cancer: The thyroid gland contains 4 tiny glands, called parathyroid glands, which are separate from the thyroid gland. The parathyroid gland regulates the body's calcium. Cancers of the gland are very rare - probably less than100 per year in the U.S. When they occur they almost always cause the blood calcium level to be elevated. This causes a person to become fatigued, weak and drowsy. It also blocks the ability of the kidneys to regulate the body's water content and excess water is lost through high volumes of urine. This further complicates the weakness and drowsiness by causing dehydration.

The cancer may also be detected as a thyroid nodule if it grows to large. No matter how large, the only treatment is surgical removal. Unfortunately, parathyroid cancer is more deadly than thyroid cancer and much harder to cure. This document only discusses thyroid cancer.

What Are the Key Statistics About Thyroid Cancer?
The American Cancer Society estimates that in the year 2006 about 30,180 new cases of thyroid cancer will be diagnosed in the United States. It is much more common in women. Of the new cases, about 22,590 will occur in women, and 7,590 in men. This is one of the least deadly cancers. The 5-year survival for all cases is nearly 97% (see below for more specific information). An estimated 870 women and 630 men (1,500 total) will die of thyroid cancer during the year 2006.

Thyroid cancer is also different in that it mainly affects younger people. Nearly two-thirds of people are diagnosed between the ages of 20 and 55.

The number of new cases of thyroid cancer is increasing. This is due to a 2% a year increase in the actual rate per 100,000 people.

What Are the Risk Factors for Thyroid Cancer?
A risk factor is anything that increases a person's chance of getting a disease such as cancer. Different cancers have different risk factors. For example, exposing skin to strong sunlight is a risk factor for skin cancer. Smoking is a risk factor for cancers of the lung, mouth, larynx, bladder, kidney, and several other organs. But having a risk factor, or even several, does not mean that a person will get the disease.

Scientists have found a few risk factors that make a person more likely to develop thyroid cancer. Most people with thyroid cancer, however, have no apparent risk factors, and other people with 1 or more risk factors never develop this disease. Even if a patient with thyroid cancer has 1 or more risk factors, it is impossible to know exactly how much that risk factor may have contributed to causing the cancer.

Diet Low in Iodine
Follicular thyroid cancers are more common in areas of the world where people's diets are low in iodine. In the United States, dietary iodine is plentiful because iodine is added to table salt and other foods. A diet low in iodine may also increase the rate of papillary cancer if there is exposure to radioactivity.

Radiation
One proven risk factor for papillary thyroid cancer is a history of head or neck radiation treatments in childhood. In the past, children were sometimes treated with radiation for acne, fungus infections of the scalp, an enlarged thymus gland, or to shrink tonsils or adenoids. Years later, studies linked these treatments to an increased risk of thyroid cancer. Radiation exposure as an adult carries little risk of thyroid cancer.

Therapeutic radiation for a cancer such as Hodgkin disease is another risk factor in children. This may be increasing as doses of radiation have been lowered. Although this avoids many of the side effects of radiation therapy, lower radiation doses can increase the risk for thyroid cancer.

Several studies have pointed to an increased risk of thyroid cancer in children, due to radioactive fallout from nuclear weapons or power plant accidents. Recently, the risk of thyroid cancer associated with exposure to nuclear fallout has received more attention in the press. For instance, there appears to be 5 to 8 times more cases of thyroid cancer than expected in children living near the Ukrainian city of Chernobyl, the site of a 1986 nuclear plant accident that exposed millions of people to fallout. People involved with the cleanup after the accident and those who lived near the plant in Ukraine and Belarus have also had a higher rate of thyroid cancer, even though they were adults. One factor that may make a difference was whether the children had adequate iodine in their diet. Children with more iodine in their diet appeared to have a lower risk. Recent information shows that some radioactive iodine fallout occurred over certain regions of the United States after nuclear weapons testing in western states during the 1950s. This exposure was much, much lower than around Chernobyl. At such low exposures, a heightened risk of thyroid cancer has not been proven. If you are concerned about possible exposure to radioactive fallout, make an appointment to discuss it with your doctor.

Hereditary Conditions
About 20% of medullary thyroid carcinomas (MTCs) result from inheriting an abnormal gene. These cases are known as familial medullary thyroid carcinoma (FMTC). The combination of FMTC and tumors of other endocrine glands is called type 2 multiple endocrine neoplasia (MEN 2). If MEN 2a, MEN 2b, or FMTC runs in your family, then you may be at very high risk of developing MTC. Ask your doctor for information about blood chemistry tests and genetic testing. There are no known risk factors for sporadic MTC.

People with certain inherited medical conditions are also at higher risk of thyroid cancer. Higher rates of the disease occur among people with conditions called Gardner syndrome and familial polyposis. These conditions cause a very high risk of colorectal cancer and a slightly increased risk of cancers in some other organs. Also linked to an increased risk of thyroid cancer is CowdenÂ's disease, a rare genetic condition.

Certain families have been found with an excess number of papillary thyroid cancers. The genetic basis for this is unknown.

Gender and Age
For unclear reasons, benign thyroid nodules and thyroid cancers occur almost 3 times more often in women than in men. Most cases of papillary and follicular thyroid cancer are found in people between the ages of 20 and 60 years. Benign thyroid nodules and thyroid cancers can occur in people of all ages.

Lifestyle Risk Factors
Although tobacco and alcohol use are the main risk factors for most types of head and neck cancer (including cancers of the mouth, throat, and esophagus). Neither of these behaviors, however, has been shown to be risk factors for thyroid cancer.

Do We Know What Causes Thyroid Cancer?
Although scientists have found that thyroid cancer is associated with a number of other conditions (described in the section, "What Are the Risk Factors for Thyroid Cancer?"), the exact cause of most thyroid cancers is not yet known.

Researchers have made great progress in understanding how certain changes in a person's DNA can cause cells of the thyroid to become cancerous. DNA is the molecule that carries the instructions for nearly everything our cells do. We usually resemble our parents because they are the source of our DNA. However, DNA affects more than our outward appearance. It also can influence our risk for developing certain diseases, such as some kinds of cancer.

Some genes (parts of our DNA) contain instructions for controlling when our cells grow and divide. Genes that can be involved in cancer are called oncogenes. Such genes are often involved in DNA maintenance or repair. Others that slow down cell division or cause cells to die at the appropriate time are called tumor suppressor genes. Cancers can be caused by DNA mutations (defects) that influence the function of these genes.

People inherit 2 copies of each gene - one from each parent. People can inherit damaged DNA from one or both parents, which accounts for inherited cancers. Many times, though, a personÂ's DNA becomes damaged by exposure to something in the environment, like smoking or exposure to radiation. Sometimes DNA mutations occur for no apparent reason.

The DNA mutations that cause some forms of papillary thyroid cancer are known to involve over-activation or specific parts of the RET oncogene. These mutations usually are acquired during life rather than being inherited. They are present only in the cancer cell and are not passed on to the patient's children. Acquired changes in other oncogenes and tumor suppressor genes (such as ras, trk, gsp, and p53) also have a role in causing papillary and follicular thyroid cancers. Recently scientists have discovered that many papillary thyroid cancers contain a mutation of the BRAF gene. The BRAF mutation is less common in cancers thought to arise from exposure to radioactive iodine -- such as around Chernobyl. This mutation is thought to cause cells to grow and divide. Researchers still do not know exactly why or how these mutations happen to some people but not to others.

Single point mutations in people who have medullary thyroid carcinoma (MTC) involve different parts of the RET gene compared to papillary carcinoma patients. Nearly all patients with the inherited form of MTC and about 1 of every 5 with the sporadic form of MTC have a mutation in the RET gene. Most patients with sporadic MTC have acquired mutations present only in their cancer cells. Those with familial MTC and MEN 2 inherit the RET mutation from a parent. These mutations are present in every cell of the patient's body and can be detected by testing the DNA of blood cells.

Because every person has 2 RET genes but passes only 1 to a child (the child's other RET gene comes from the other parent), the odds that a patient with familial MTC will pass a mutated gene to a child are 1 of 2 (or a 50% chance). RET gene mutations do not occur in follicular cancer. These cancers sometimes have changes to other oncogenes and/or tumor suppressor genes. Undifferentiated thyroid cancers often have acquired (not inherited) mutations of the p53 tumor suppressor gene.

Can Thyroid Cancer Be Prevented?
Most people with thyroid cancer have no known risk factors; therefore, it is not possible to reliably prevent most cases of this disease. Some doctors have suggested that the increase in thyroid cancers may be due to x-ray testing of young children. This has not been proven, but it is a good idea for children to avoid x-rays that arenÂ't necessary.

Because of the genetic blood tests now available, most of the familial cases of medullary thyroid carcinoma (MTC) can be treated early or prevented. Once the disease is discovered in a family, the rest of the family can be tested.

If you have a family history of MTC, it is important that you see a doctor who is familiar with the latest advances in genetic counseling and genetic testing for this disease. Removing the thyroid gland in children who carry the abnormal gene will prevent a cancer that might otherwise be fatal.

Can Thyroid Cancer Be Found Early?
Many cases of thyroid cancer can be found early. In fact, most thyroid cancers are now found much earlier than in the past and can be treated successfully. Although it's unusual, some thyroid cancers may not cause symptoms until after reaching an advanced stage. Most early thyroid cancers are found when patients ask their doctors about lumps or nodules they have noticed. Others are found by health care professionals during a routine checkup. No blood tests are regularly recommended for early detection of sporadic (not familial) thyroid cancers.

If you have unusual symptoms such as a lump or your neck looks swollen, you should make an appointment to see your doctor right away. During routine physical examinations, be sure your doctor does a cancer-related checkup that, depending on your age, might include examinations for cancers of the thyroid, mouth, skin, lymph nodes, and other cancers. Some doctors recommend that people examine their own necks twice a year to look for any growths or lumps.

People with a family history of medullary thyroid carcinoma (MTC) with or without type 2 multiple endocrine neoplasia (MEN 2) may be at very high risk for developing this cancer. Most doctors recommend genetic testing for these people when they are young to see if they carry the gene for MTC. If a person refuses genetic testing and surgery to prevent MTC, other tests are available that can help find MTC at an early stage when it may still be curable.

How is Thyroid Cancer Diagnosed?
Signs and Symptoms of Thyroid Cancer
Prompt attention to signs and symptoms is the best approach to early diagnosis of most thyroid cancers. Thyroid cancer can cause any of the following local signs or symptoms:

• a lump in the neck, sometimes growing rapidly
• a pain in the front of the neck, sometimes going up to the ears
• hoarseness or voice change which does not go away
• trouble swallowing
• breathing problems (feeling as if one were •breathing through a straw•)
• a cough that continues and is not due to a cold

If you have any of these signs or symptoms, talk to your doctor right away. Other cancers of the neck area and many noncancerous conditions can cause some of the same symptoms. Thyroid nodules are common, and they are usually benign. But the only way to find out if these symptoms are due to a thyroid cancer, some other cancer, or a benign condition is to have a medical evaluation. The sooner you receive a correct diagnosis, the sooner you can start treatment and the more effective your treatment will be.

History and Physical Examination
If you have any signs or symptoms that suggest you might have thyroid cancer, the first step toward arriving at a diagnosis is for your health care professional to take a complete medical history. This is an interview in which you will be asked questions about your risk factors, symptoms, and any other health problems or concerns. If someone in your family has had thyroid cancer (especially medullary thyroid cancer) or adrenal gland tumors called pheochromocytomas, it is important to tell your doctor.

A physical exam will provide other information about signs of thyroid cancer and other health problems. During your physical exam, your doctor will pay special attention to the size and firmness of your thyroid and any enlarged lymph nodes in your neck.

Fine Needle Aspiration Biopsy
The simplest way to test whether a thyroid lump or nodule is cancerous is with a fine needle aspiration (FNA) of the thyroid nodule. This type of biopsy can usually be done in your doctor's office or clinic. Local anesthesia (numbing medication) may be injected into the skin over the nodule, but in some cases an anesthetic may not be needed at all. The major complication is bleeding, but this is rare except in people with bleeding disorders. Be sure to tell your doctor is you have a bleeding disorder.

Your doctor will place a thin needle directly into the nodule for about 10 seconds and withdraws cells and a few drops of fluid. The doctor usually repeats this procedure 2 or 3 times during the same appointment to take samples from several areas of the nodule. The cells can then be viewed under a microscope to see if they appear cancerous or benign.

This test is generally done on all thyroid nodules that are large enough to be felt. Sometimes FNA tests are done with ultrasound machines to help guide the needle into nodules that are otherwise too small to be felt. FNA can help your doctor decide if surgery or other tests are needed.

About 1 test in every 10 will need to be repeated on another day. Of every 10 FNA tests, up to 8 clearly show that the nodule is benign. Cancer is clearly shown in only 1 of every 20 FNA tests. Some test results are classified as "suspicious" or "atypical" because the FNA findings do not clearly show whether the nodule is benign or malignant. In these cases, additional tests such as a diagnostic surgical lobectomy (i.e. removal of the gland on one side of the windpipe) may be needed, particularly if the doctor thinks the nodule is cancerous.

A new way of testing the thyroid cells is by examining their genetic profile. This is too new to be used in most situations, but may play a role in the future.

Imaging Tests
Thyroid scan: For this test, a small amount of radioactive iodine is taken by mouth or injected into a vein. The body concentrates these radioactive chemicals in the thyroid gland, and a special camera placed in front of your neck then measures the amount of radiation in the gland. Abnormal areas of the thyroid that contain less radioactivity than the surrounding tissue are called cold nodules, and nodules that take up more radiation are called hot nodules.
Most thyroid nodules appear as cold nodules on thyroid scans. Because both benign and cancerous nodules can appear cold, this test is usually not very helpful in diagnosing thyroid cancer. However, once a biopsy has determined that a thyroid cancer is present, scans are very useful in follow-up for potential spread. Scans following initial surgical treatment can also help assess how far a thyroid cancer has initially spread, if at all.

If the entire thyroid gland is removed for cancer, repeated thyroid scans will be done. The test becomes more sensitive in this instance because more of the injected radioactive iodine enters thyroid cancer cells. Radioiodine scans are frequently used in the care and management of
patients with differentiated (papillary and follicular and Hurthle cell) thyroid cancer. Because MTC cells do not take up iodine, radioiodine scans are not used in this cancer.

Radioiodine thyroid scans are most accurate if patients have high blood levels of thyroid-stimulating hormone (TSH, or thyrotropin). In the past, the only way to increase TSH levels in patients whose thyroid glands had been surgically removed was to stop thyroid hormone pills 2 to 6 weeks before treatment. This lowers thyroid hormone levels (a condition known as hypothyroidism) and causes the pituitary gland to release more TSH, which in turn stimulates the cancer cells to take up the radioactive iodine. Although this intentional hypothyroidism is temporary, it is sometimes uncomfortable for the patient. Symptoms include tiredness, depression, some weight gain, sleepiness, constipation, muscle aches, and reduced concentration, in addition to other conditions. An injectable form of thyrotropin is now available that can increase patients' TSH levels before radioiodine scanning so that withholding thyroid hormone replacement is not necessary.

Ultrasound: Ultrasound, or ultrasonography, uses sound waves to create images of your body. A transducer held near your thyroid gland gives off high-frequency sound waves and detects echoes that bounce off thyroid tissue. Normal thyroid tissue and most thyroid nodules make different echo patterns. These echo patterns are processed by a computer to create a picture of the thyroid gland. This test can be used to check the number and size of thyroid nodules. However, thyroid cancers and most benign nodules look the same on ultrasound studies, so this test is not done routinely.

Computed tomography (CT or CT scan): The CT scan is an x-ray procedure that produces detailed cross-sectional images of your body. Instead of taking one picture, as does a normal x-ray, a CT scanner takes many pictures of the part of your body being studied as it rotates around you. A computer then combines these pictures into an image of a slice of your body. A CT scan isnÂ't usually used to diagnose thyroid cancer, but might be used to see if a known thyroid cancer has spread.

Magnetic resonance imaging (MRI or MRI scan): MRI scans use radio waves and strong magnets instead of x-rays. The energy from the radio waves is absorbed and then released in a pattern formed by the type of tissue and by certain diseases. A computer translates the pattern of radio waves given off by the tissues into a very detailed image of parts of the body. A contrast material might be injected just as with CT scans. MRI scans are very helpful in looking at cancers. Sometimes they can tell a benign tumor from a malignant one.

MRI scans take longer than CT scans - often up to an hour. Also, you have to lie inside a narrow tube, which is confining and can upset people with a fear of enclosed spaces. The machine makes a thumping noise, and some facilities provide headphones with music to block out the noise. However the benefits of the test outweigh any discomfort.

MRI and CT scans can reveal tumors within a thyroid gland but may also determine the size of the tumor, whether it is growing into nearby tissues, and if it has spread to lymph nodes in the neck or distant structures.

Octreotide scan: Sometimes an octreotide scan, which uses a radioactively tagged hormone, may be done to evaluate the spread of medullary thyroid cancer.

Positron emission tomography (PET): Positron emission tomography (PET) uses glucose (a form of sugar) that contains a radioactive atom. Cancer cells in the body absorb large amounts of the radioactive sugar and a special camera can detect the radioactivity. This can be a very important test if your thyroid cancer is one that doesnÂ't take up radioactive iodine. In this
situation, the PET scan may be able to tell if the cancer has spread. Newer techniques and devices can combine a CT scan and a PET scan to even better pinpoint tumor spread

Blood Tests
No blood test can tell whether a thyroid nodule is cancerous. However, testing your blood levels of thyroid-stimulating hormone (TSH) may be useful in checking the overall activity of your thyroid gland. If medullary thyroid carcinoma (MTC) is suspected, a blood calcitonin test will be done. This test can help tell if MTC is present.

Thyroglobulin is a protein manufactured by the thyroid gland. Its measurement cannot be used to diagnose thyroid cancer. However, after the removal of most of the thyroid by surgery and ablation of residual normal cells by radioactive iodine, its level in the blood should be very low. If it is not low, this might mean that thyroid cancer is still present. If the level rises, it is a sign that the cancer may be coming back.

How Is Thyroid Cancer Treated?
After thyroid cancer is found, your doctor will discuss treatment options or choices with you. It is important to take the time to consider each of them. In choosing a treatment plan, factors to consider include the type and stage of the cancer and your overall physical health. Sometimes it is a good idea to seek a second opinion, and many experienced physicians encourage this. Some insurance companies even require a second opinion before they will agree to pay for certain treatments. A second opinion can provide more information and help you feel confident about the treatment plan you choose.

The methods of treatment for thyroid cancer include surgery, radioactive iodine treatment, thyroid hormone therapy, external beam radiation therapy, and chemotherapy. The best approach to treatment usually uses 2 or more of these methods, and most patients are cured of their thyroid cancer in this way.

If a cure is not possible, the goal may be to remove or destroy as much of the cancer as possible and to prevent the tumor from growing, spreading, or returning for as long as possible. Sometimes treatment is aimed at palliation (relieving symptoms, such as pain or problems with breathing and swallowing), even if a cure will not result.

Clinical Trials
The purpose of clinical trials: Studies of promising new or experimental treatments in patients are known as clinical trials. A clinical trial is only done when there is some reason to believe that the treatment being studied may be valuable to the patient. Treatments used in clinical trials are often found to have real benefits. Researchers conduct studies of new treatments to answer the following questions:

• Is the treatment helpful?
• How does this new type of treatment work?
• Does it work better than other treatments already available?
• What side effects does the treatment cause?
• Are the side effects greater or less than the standard treatment?
• Do the benefits outweigh the side effects?
• In which patients is the treatment most likely to be helpful?

Types of clinical trials: There are 3 phases of clinical trials in which a treatment is studied before it is eligible for approval by the FDA (Food and Drug Administration).


Phase I clinical trials: The purpose of a phase I study is to find the best way to give a new treatment and how much of it can be given safely. The cancer care team watches patients carefully for any harmful side effects. The treatment has been well tested in lab and animal studies, but the side effects in patients are not completely known. Doctors conducting the clinical trial start by giving very low doses of the drug to the first patients and increasing the dose for later groups of patients until side effects appear. Although doctors are hoping to help patients, the main purpose of a phase I study is to test the safety of the drug.

Phase II clinical trials: These studies are designed to see if the drug works. Patients are given the highest dose that doesnÂ’t cause severe side effects (determined from the phase I study) and closely observed for an effect on the cancer. The cancer care team also looks for side effects.

Phase III clinical trials: Phase III studies involve large numbers of patient - often several hundred. One group (the control group) receives the standard (most accepted) treatment. The other group receives the new treatment. All patients in phase III studies are closely watched. The study will be stopped if the side effects of the new treatment are too severe or if one group has had much better results than the others.

If you are in a clinical trial, you will have a team of experts watching your progress very carefully.
The study is especially designed to pay close attention to you.

However, there are some risks. No one involved in the study knows in advance whether the treatment will work or exactly what side effects will occur. That is what the study is designed to find out. While most side effects disappear in time, some can be permanent or even life threatening. Keep in mind, though, that even standard treatments have side effects. Depending on many factors, you may decide to enroll in a clinical trial.

Deciding to enter a clinical trial: Enrollment in any clinical trial is completely up to you. Your doctors and nurses will explain the study to you in detail and will give you a form to read and sign indicating your desire to take part. This process is known as giving your informed consent. Even after signing the form and after the clinical trial begins, you are free to leave the study at any time, for any reason. Taking part in the study does not prevent you from getting other medical care you may need.

Courtesy: www.cancer.org, Please visit the website for further information