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February 10, 2012


Thyroid Cancer Glossary of Terms

The following are health and medical definitions of terms that appear in the Thyroid Cancer article.

Adam's apple: A familiar anatomic feature in the front of the neck that is due to the forward protrusion of the thyroid cartilage, the largest and most prominent cartilage of the larynx.
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Adjuvant: The Latin "adjuvans" means to help, particularly to reach a goal.
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Aging: The process of becoming older, a process that is genetically determined and environmentally modulated.
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Analysis: A psychology term for processes used to gain understanding of complex emotional or behavioral issues.

Aspiration: Removal of a sample of fluid and cells through a needle. Aspiration also refers to the accidental sucking in of food particles or fluids into the lungs.

Benign: Not cancer. Not malignant. A benign tumor does not invade surrounding tissue or spread to other parts of the body. A benign tumor may grow but it stays put (in the same place).
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction, and then exhaled due to muscle relaxation.

Bridge: A set of one or more false teeth supported by a metal framework, used to replace one or more missing teeth.
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Calcitonin: A hormone produced by the thyroid gland that lowers the levels of calcium and phosphate in the blood and promotes the formation of bone.
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Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
See the entire definition of Cancer

Cancer causes: In most individual cases of cancer, the exact cause of cancer is unknown. The causes may include increased genetic susceptibility; environmental insults, such as chemical exposure or smoking cigarettes; lifestyle factors, including diet; damage caused by infectious disease; and many more.
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Cancer registry: A register designed to collect information about the occurrence (incidence) of cancer, the types of cancers that occur and their locations within the body, the extent of cancer at the time of diagnosis (disease stage), and the kinds of treatment that patients receive. In the US, these data are reported to a central statewide registry from various medical facilities, including hospitals, physicians' offices, therapeutic radiation facilities, freestanding surgical centers, and pathology laboratories.
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Cancer symptoms: Abnormal sensations or conditions that persons can notice that are a result of a cancer. It is important to see your doctor for regular checkups and not wait for problems to occur. But you should also know that the following symptoms may be associated with cancer: changes in bowel or bladder habits, a sore that does not heal, unusual bleeding or discharge, thickening or lump in the breast or any other part of the body, indigestion or difficulty swallowing, obvious change in a wart or mole, or nagging cough or hoarseness. These symptoms are not always a sign of cancer. They can also be caused by less serious conditions. Only a doctor can make a diagnosis. It is important to see a doctor if you have any of these symptoms. Don't wait to feel pain. Early cancer often does not cause pain.

Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast, colon, liver, lung, prostate, and stomach.

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Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane.
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Chemotherapy: 1. In the original sense, a chemical that binds to and specifically kills microbes or tumor cells. The term chemotherapy was coined in this regard by Paul Ehrlich (1854-1915).
2. In oncology, drug therapy for cancer. Also called "chemo" for short.
See the entire definition of Chemotherapy

Computerized tomography: Pictures of structures within the body created by a computer that takes the data from multiple X-ray images and turns them in pictures.
See the entire definition of Computerized tomography

Contrast: Short for "contrast media." Contrast media are X-ray dyes used to provide contrast, for example, between blood vessels and other tissue.

Cough: A rapid expulsion of air from the lungs typically in order to clear the lung airways of fluids, mucus, or material. Also called tussis.

Cure: 1. To heal, to make well, to restore to good health. Cures are easy to claim and, all too often, difficult to confirm.
2. A time without recurrence of a disease so that the risk of recurrence is small, as in the 5-year cure rate for malignant melanoma.
3. Particularly in the past, a course of treatment. For example, take a cure at a spa.
See the entire definition of Cure

Diagnosis: 1 The nature of a disease; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies. 3 The identification of any problem. The diagnosis was a plugged IV.
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DNA: Deoxyribonucleic acid. One of two types of molecules that encode genetic information. (The other is RNA. In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.)
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Endocrine: Pertaining to hormones and the glands that make and secrete them into the bloodstream through which they travel to affect distant organs. The endocrine sites include the hypothalamus, pituitary gland, pineal gland, thyroid, parathyroids, heart (which makes atrial-natriuretic peptide), the stomach and intestines, islets of Langerhans in the pancreas, the adrenal glands, the kidney (which makes renin, erythropoietin, and calcitriol), fat cells (which make leptin). the testes, the ovarian follicle (estrogens) and the corpus luteum in the ovary). Endocrine is as opposed to exocrine. (The exocrine glands include the salivary glands, sweat glands and glands within the gastrointestinal tract.)
See the entire definition of Endocrine

Endocrinology: The study of hormones, their receptors, the intracellular signalling pathways they invoke, and the diseases and conditions associated with them.
See the entire definition of Endocrinology

Familial: A condition that is tends to occur more often in family members than expected by chance alone. A familial disease may be genetic (such as cystic fibrosis) or environmental (such as tuberculosis).

Fine needle aspiration: The use of a thin needle to withdraw material from the body. For example, this method is commonly used to determine whether a nodule in the thyroid gland is benign or malignant (fine needle aspiration biopsy of the thyroid). A fine gauge needle is placed into the nodule and a drop of blood is withdrawn. The cells are studied under the microscope by an pathologist.

Gene: The basic biological unit of heredity. A segment of deoxyribonucleic acid (DNA) needed to contribute to a function.
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Genetic: Having to do with genes and genetic information.

Genetic testing: Tests done for clinical genetic purposes. Genetic tests may be done for diverse purposes pertaining to clinical genetics, including the diagnosis of genetic disease in children and adults; the identification of future disease risks; the prediction of drug responses; and the detection of risks of disease to future children.

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GI tract: Short for gastrointestinal tract. See: Gastrointestinal tract.

Gland: 1. A group of cells that secrete a substance for use in the body. For example, the thyroid gland. 2. A group of cells that removes materials from the circulation. For example, a lymph gland.

Hoarseness: Hoarseness is a term referring to abnormal voice changes. Hoarseness may be manifested as a voice that sounds breathy, strained, rough, raspy, or a voice that has higher or lower pitch. There are many causes of hoarseness, including viral laryngitis, vocal cord nodules, laryngeal papillomas, gastroesophageal reflux-related laryngitis, and environmental irritants (such as tobacco smoking). An accumulation of fluid in the vocal cords associated with hoarseness has been termed Reinke's edema. Reinke's edema may occur as a result of cigarette smoking or voice abuse (prolonged or extended talking or shouting). Rarely, hoarseness results from serious conditions such as cancers of the head and neck region.

Hormone: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs.
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Hypothyroid: Deficiency of thyroid hormone which is normally made by the thyroid gland which is located in the front of the neck:

Incidence: The frequency with which something, such as a disease, appears in a particular population or area. In disease epidemiology, the incidence is the number of newly diagnosed cases during a specific time period. The incidence is distinct from the prevalence which refers to the number of cases alive on a certain date.

Indicate: In medicine, to make a treatment or procedure advisable because of a particular condition or circumstance. For example, certain medications are indicated for the treatment of hypertension during pregnancy while others are contraindicated.

Iodine: An essential element in the diet used by the thyroid gland to make thyroid hormones.
See the entire definition of Iodine

Laboratory: A place for doing tests and research procedures and preparing chemicals, etc. Although "laboratory" looks very like the Latin "laboratorium" (a place to labor, a work place), the word "laboratory" came from the Latin "elaborare" (to work out, as a problem, and with great pains), as evidenced by the Old English spelling "elaboratory" designating "a place where learned effort was applied to the solution of scientific problems."

Lobectomy: An operation done to remove a lobe of an organ such as the lobe of a lung or a lobe of the thyroid gland.
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Lungs: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.

Lymphoma: Tumor of the lymphoid tissue. Diagnosis is by biopsy. Treatment may be chemotherapy, radiation, surgery, or medication, depending on the age of the patient and type of tumor.

Malignancy: A tumor that is malignant, that is cancerous, that can invade and destroy nearby tissue, and that may spread (metastasize) to other parts of the body.

Marker: A piece of DNA that lies on a chromosome so close to a gene that the marker and the gene are inherited together. A marker is thus an identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA (a gene) or a segment of DNA with no known coding function. All that matters is that the marker can be detected and trailed.
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Metastasis: 1. The process by which cancer spreads from the place at which it first arose as a primary tumor to distant locations in the body.
2. The cancer resulting from the spread of the primary tumor. For example, someone with melanoma may have a metastasis in their brain. And a person with colon cancer may, fortunately, show no metastases.
See the entire definition of Metastasis

Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

Mutation: A permanent change, a structural alteration, in the DNA or RNA. In humans and many other organisms, mutations occur in DNA. However, in retroviruses like HIV, mutations occur in RNA which is the genetic material of retroviruses.
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Neck: The part of the body joining the head to the shoulders. Also, any narrow or constricted part of a bone or organ that joins its parts as, for example, the neck of the femur bone.

Neck pain: Neck pain is the sensation of discomfort in the neck area. Neck pain can result from disorders of any of the structures in the neck, including the cervical vertebrae and intervertebral discs, nerves, muscles, blood vessels, esophagus, larynx, trachea, lymphatic organs, thyroid gland, or parathyroid glands. Neck pain arises from numerous different conditions and is sometimes referred to as cervical pain.

Neoplasia: The process of abnormal and uncontrolled growth of cells. The product of neoplasia is a neoplasm (a tumor).

Nodule: A small solid collection of tissue, a nodule is palpable (can be felt). It may range in size from greater than 1.0 cm (3/8 inch) to somewhat less than 2 cm (13/16 inch) in diameter. A nodule may be present in the epidermis, dermis or subcutis (at any level in the skin).
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Nuclear medicine: The branch of medicine concerned with the use of radioisotopes in the diagnosis, management, and treatment of disease. Nuclear medicine uses small amounts of radioactive materials or radiopharmaceuticals, substances that are attracted to specific organs, bones, or tissues. The radiopharmaceuticals used in nuclear medicine emit gamma rays that can be detected externally by special types of cameras: gamma or PET cameras. These cameras work in conjunction with computers used to form images that provide data and information about the area of body being imaged. The amount of radiation from a nuclear medicine procedure is comparable to that received during a diagnostic x-ray.

Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia. Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Pathologist: A doctor who identifies diseases by studying cells and tissues under a microscope.

Pregnant: The state of carrying a developing fetus within the body.
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Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.

Protein: A large molecule composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Proto-oncogene: A normal gene which, when altered by mutation, becomes an oncogene that can contribute to cancer. Proto-oncogenes may have many different functions in the cell. Some proto-oncogenes provide signals that lead to cell division. Other proto-oncogenes regulate programmed cell death (apoptosis).
See the entire definition of Proto-oncogene

Radiation: 1. Rays of energy. Gamma rays and X-rays are two of the types of energy waves often used in medicine. 2. The use of energy waves to diagnose or treat disease. See also: Irradiation.

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Radiation therapy: The use of high-energy rays to damage cancer cells, stopping them from growing and dividing. Like surgery, radiation therapy is a local treatment that affects cancer cells only in the treated area.
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Radioactive: Emitting energy waves due to decaying atomic nuclei. Radioactive substances are used in medicine as tracers for diagnosis, and in treatment to kill cancerous cells.

Radioactive iodine: An isotope of the chemical element iodine that is radioactive. Radioactive iodine is used in diagnostic tests as well as in radiotherapy of an hyperactive thyroid gland (hyperthyroidism), most often due to Graves' disease.
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Recurrence: The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence.
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Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

Registry: Although a registry was originally the place (like Registry House in Edinburgh) where information was collected (in registers), the word registry has also come to mean the collection itself. A registry is usually organized so the data can be analyzed. For example, analysis of data in a tumor registry maintained at a hospital may show a rise in lung cancer among women.

Residual: Something left behind. With residual disease, the disease has not been eradicated.

Sarcoma: One of a group of tumors usually arising from connective tissue. Most sarcomas are malignant. Many types are named after the type of cell, tissue, or structure involved, as in angiosarcoma, chondrosarcoma, fibrosarcoma, liposarcoma,and osteosarcoma.

Scan: As a noun, the data or image obtained from the examination of organs or regions of the body by gathering information with a sensing device.
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SEER: The Surveillance, Epidemiology, and Ends Results (SEER) program that maintains statistics on cancer in the US. SEER is part of the National Cancer Institute. For more information, see: SEER program.

Surgeon: A physician who treats disease, injury, or deformity by operative or manual methods. A medical doctor specialized in the removal of organs, masses and tumors and in doing other procedures using a knife (scalpel). The definition of a "surgeon" has begun to blur in recent years as surgeons have begun to minimize the cutting, employ new technologies that are "minimally invasive," use scopes, etc.
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Surgery: The word "surgery" has multiple meanings. It is the branch of medicine concerned with diseases and conditions which require or are amenable to operative procedures. Surgery is the work done by a surgeon. By analogy, the work of an editor wielding his pen as a scalpel is s form of surgery. A surgery in England (and some other countries) is a physician's or dentist's office.
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Syringe: A device used in medicine to inject fluid into or withdraw fluid from the body. Medical syringes consist of a needle attached to a hollow cylinder that is fitted with a sliding plunger. The downward movement of the plunger injects fluid; upward movement withdraws fluid.
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Therapy: The treatment of disease.
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Throat: The throat is the anterior (front) portion of the neck beginning at the back of the mouth, consisting anatomically of the pharynx and larynx. The throat contains the trachea and a portion of the esophagus.

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Thyroglobulin: A protein found in the thyroid gland. Some thyroglobulin can be found in the blood, and this amount may be measured after thyroid surgery to determine whether thyroid cancer has recurred. Thyroglobulin derived from pig thyroid glands is sometimes given to treat thyroid dysfunction. Abbreviated Tg.

Thyroid: 1. The thyroid gland. Also, pertaining to the thyroid gland. 2. A preparation of the thyroid gland used to treat hypothyroidism. 3. Shaped like a shield. (The thyroid gland was so-named by Thomas Wharton in 1656 because it was shaped like an ancient Greek shield.)
See the entire definition of Thyroid

Thyroid cancer: Cancer of the gland in front of the neck that normally produces thyroid hormone which is important to the normal regulation of the metabolism of the body. There are 4 major types of thyroid cancer -- papillary, follicular, medullary, and anaplastic. The most common symptom of thyroid cancer is a lump, or nodule, that can be felt in the neck. The only certain way to tell whether a thyroid lump is cancer is by examining the thyroid tissue, obtained using a needle or surgery to obtain a biopsy.


See the entire definition of Thyroid cancer

Thyroid gland: A gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and the rate at which food is converted into energy. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism) in the body. Thyroid hormones also help children grow and develop.
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Thyroid hormone: A chemical substance made by the thyroid gland for export into the bloodstream. The thyroid gland needs iodine to make thyroid hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine (T3).
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Thyroid hormones: Chemical substances made by the thyroid gland, which is located in the front of the neck. This gland uses iodine to make thyroid hormones, which are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions (metabolism), and are involved in the circadian rhythms that govern sleep, among other essential functions.
See the entire definition of Thyroid hormones

Thyroid scan: An image taken of the thyroid gland after radioactive iodine is taken by mouth. The thyroid gland is in front of the neck:


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Thyroidectomy: The surgical removal of part or all of the thyroid gland.


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Thyrotropin: A hormone produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain.
See the entire definition of Thyrotropin

Tomography: The process for generating a tomogram, a two-dimensional image of a slice or section through a three-dimensional object. Tomography achieves this remarkable result by simply moving an x-ray source in one direction as the x-ray film is moved in the opposite direction during the exposure to sharpen structures in the focal plane, while structures in other planes appear blurred. The tomogram is the picture; the tomograph is the apparatus; and tomography is the process.
See the entire definition of Tomography

Trachea: A tube-like portion of the breathing or "respiratory" tract that connects the "voice box" (larynx) with the bronchial parts of the lungs.


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TSH: Stands for thyroid stimulating hormone, a hormone produced by the pituitary gland at the base of the brain in response to signals from the hypothalamus gland in the brain. TSH promotes the growth of the thyroid gland in the neck and stimulates it to produce more thyroid hormones. When there is an excessive amount of thyroid hormones, the pituitary gland stops producing TSH, reducing thyroid hormone production. This mechanism maintains a relatively constant level of thyroid hormones circulating in the blood.
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Tumor: An abnormal mass of tissue. Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous). There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell you something about their shape or how they grow. For example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla). Diagnosis depends on the type and location of the tumor. Tumor marker tests and imaging may be used; some tumors can be seen (for example, tumors on the exterior of the skin) or felt (palpated with the hands).
See the entire definition of Tumor

Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.

Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis).

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Windpipe: The trachea, a tube-like portion of the respiratory (breathing) tract that connects the larynx (the voicebox) with the bronchial parts of the lungs.


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Thyroid Cancer

Topic Overview

What is thyroid cancer?

Thyroid cancer is a disease that you get when abnormal cells begin to grow in your thyroid gland. The thyroid gland is shaped like a butterfly and is located in the front of your neck. It makes hormones that regulate the way your body uses energy and that help your body work normally.

Thyroid cancer is an uncommon type of cancer. Most people who have it do very well, because the cancer is usually found early and the treatments work well. After it is treated, thyroid cancer may come back, sometimes many years after treatment.

What causes thyroid cancer?

Experts do not know the exact cause of thyroid cancer. Like other cancers, changes in the DNA of your cells seem to play a role. These DNA changes may include changes that are inherited as well as those that happen as you get older. People who have been exposed to a lot of radiation have a greater chance of getting thyroid cancer.

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