A clinical trial in which doctors and participants know which treatment is being administered to which patients.
Papillary cancer
A well-differentiated thyroid cancer composed of thyroid follicular cells. Also called papillary carcinoma. The nuclei of the cells are large and seem to overlap.
Parathyroid glands
Four glands located on the back of the thyroid that produce parathyroid hormone.
Paresthesia
Burning, prickling, or tingling sensation in the skin.
PET (positron emission tomography) scan
An imaging technique that uses radioactive positrons (positively charged particles) to detect subtle changes in the body's metabolism and chemical activities.
Pituitary gland
A small gland the size of a peanut that is located behind the eyes at the base of the brain. It secretes hormones that control other glands (including the thyroid) as well as growth. It secretes thyroid stimulating hormone (TSH), a hormone that helps control thyroid function, as well as other hormones involved in endocrine function.
Prognostic indicators
Factors that can help predict a likely outcome (as in how, on average, thyroid cancer will progress).
Quality of life (QOL)
A person’s physical, mental, and social well-being. Also known as health-related quality of life (HRQOL).
Radioactive iodine (RAI)
Radioactive isotopes of iodine (131I or 123I) used in the diagnosis and treatment of some thyroid disorders. RAI is also used for treatment of thyroid cancer, in which cases the patient takes a large dose of radioactive iodine to kill any recurrent or metastasized thyroid cells.
Radioactive iodine uptake (RAIU)
A test measuring the amount of orally administered radioactive iodine taken up by the thyroid gland.
Radioactive isotopes
Unstable chemical elements that are used in diagnostic testing for thyroid disorders including thyroid cancer.
RAI ablation
Administration of a radioactive form of iodine (131I) to try to destroy any remnant (normal or cancerous) thyroid tissue left after surgery in the thyroid bed or neck.
Recombinant DNA technology
The technique of isolating genes from one organism and purifying and reproducing them in another organism; sometimes called genetic engineering.
Recombinant human thyroid-stimulating hormone (rhTSH) -
A large protein molecule almost identical to human thyroid-stimulating hormone that has been produced using recombinant DNA technology. Also known as Thyrogen.
Scintigraphy
A diagnostic procedure using a radioactive agent with affinity for the tissue of interest followed by a whole body scan.
Sensitivity
The ability of a test to detect the proportion of true positive results for the disease that the test is intended to reveal. In other words, the probability that, given the presence of disease, a test result indicates the presence of disease.
Signs
Those characteristics that a physician can objectively detect or measure. If the physician touches the patient's skin and notes that it is warm and moist, this is a sign. (See symptoms.)
Specificity
The ability of a test to detect the proportion of true negative results for the disease that the test is intended to reveal. In other words, the probability that, given the absence of disease, a test result excludes disease.
Standardized
Using different techniques or preparations in order to conform to a reference or standard.
Statistics
The study of probabilities. Statistics are used in clinical trials to determine whether results obtained with the study drug are truly different from those obtained with the control (or placebo).
Symptoms
Those problems that a patient notices or feels. If a patient feels hot, this is a symptom.
T3 (triiodothyronine)
The secondary hormone produced by the thyroid gland.
T4 (thyroxine)
The primary hormone produced by the thyroid gland.
Tg test
A test that measures the level of thyroglobulin (Tg) in the blood. Tg tests are used in the postsurgical monitoring of thyroid cancer patients to check for thyroid remnants or cancer metastases.
THT (thyroid hormone therapy)
Therapy consisting of thyroid hormone medications.
Thyroglobulin (Tg)
A large protein that acts as a storage site for thyroid hormones within the thyroid gland. Following surgical removal of a cancerous thyroid gland, the level of Tg in the bloodstream can be monitored to detect thyroid cancer recurrence.
Thyroid bed
The area of the thyroid that remains after surgical removal of the thyroid gland.
Thyroid-binding proteins
Proteins to which thyroid hormones attach themselves and thus circulate in the bloodstream.
Thyroid gland
A two-lobed gland lying at the base of the throat that produces hormones essential for a variety of metabolic processes in the body. When iodine is ingested, much of it goes to the thyroid gland.
Thyroid hormone suppression therapy (THST)
In patients who have had a thyroidectomy for thyroid cancer, physicians usually prescribe a moderate excess of thyroid hormones to create a negative feedback loop that suppresses thyroid-stimulating hormone production by the pituitary gland. TSH production is suppressed to avoid stimulating existing thyroid remnants or thyroid cancer cells.
Thyroid hormones
T4 and T3, two hormones that tell the body how fast to work and how to use energy. T4 (thyroxine) is the primary hormone produced by the thyroid gland and T3 (triiodothyronine) is the secondary hormone produced by the thyroid gland.
Thyroid nodules
Small lumps or growths that can be felt in the neck. They can be benign or malignant. In a normal gland or a multinodular goiter, thyroid nodules may be solitary or multiple. Imaging tests, blood tests, and fine needle aspiration biopsies (FNAB) are used to perform a clinical evaluation of thyroid nodules.
Thyroid remnant
Some part of the original thyroid gland remaining after thyroidectomy surgery.
Thyroid scan
A picture of the thyroid gland obtained with a rectilinear scanner and radioactive materials.
Thyroid-stimulating hormone (TSH )
A hormone secreted by the pituitary gland that stimulates the thyroid gland to produce the thyroid hormones T4 and T3. When the thyroid gland is not working properly, the pituitary releases large amounts of TSH to try to stimulate the thyroid gland into producing thyroid hormone. High amounts of TSH circulating in the bloodstream thus indicate that the thyroid is not secreting enough hormones.
Thyroid ultrasound
A type of scan that uses sound waves that pass into the body and reflect back to produce images.
Thyroidectomy
Surgical removal of the thyroid gland.
Thyroiditis
Inflammation of the thyroid gland.
Thyroidologists
Doctors who specialize in the treatment of diseases of the thyroid.
Thyrotropin alfa
The generic name for Thyrogen®.
Thyrotropin receptor
The matching site on a thyroid cell that selectively captures thyroid stimulating hormone (TSH) to stimulate the production of thyroid hormones by the thyroid gland.
Thyrotropin
Another name for thyroid-stimulating hormone (TSH).
Thyrotropin-releasing hormone (TRH)
A hormone released by the hypothalamus that stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH). Also called thyroliberin.
Thyroxine (T4)
The primary hormone produced by the thyroid gland. T4 contains four atoms of iodine.
TNM
A tumor staging system for classifying patients with thyroid cancer into groups based on tumor size (T), presence of lymph node metastases (N), and the presence of distant metastases (M). Also referred as “tumor-node-metastasis.”
Toxic multinodular goiter (TMNG)
A thyroid gland that has multiple nodules functioning independently of the usual control mechanisms. They can cause the thyroid to produces too much thyroid hormone and cause hyperthyroidism.
Trachea
The windpipe.
Triiodothyronine (T3)
The secondary hormone produced by the thyroid gland. It contains three atoms of iodine and is the metabolically active thyroid hormone.
TSH test
A test to measure the amount of thyroid-stimulating hormone (TSH) in the bloodstream.
Ultrasound
An imaging technique used to obtain pictures by bouncing sound waves off an object.
Undifferentiated thyroid cancer
A form of thyroid cancer in which the cancer cells do not resemble thyroid cells.
Well-differentiated thyroid cancers
Papillary or follicular thyroid cancers showing well-differentiated cell structures.
Whole body scan (WBS)
A scan of the whole body used to view areas of radioactive iodine uptake after its oral administration.
Withdrawal scan
A radioactive iodine (131I) whole body scan performed when the patient has been withdrawn from thyroid hormone suppression therapy long enough for thyroid-stimulating hormone (TSH) levels to rise.
* Levothroid®
is a registered trademark of Forest Pharmaceuticals, Inc.
*Levoxyl®
is a registered trademark of Jones Pharma® Incorporated.
*Synthroid®
is a registered trademark of Abbott Laboratories.
*Unithroid®
is a registered trademark of Watson Pharma, Inc.
