What is cancer of the thyroid? Cancer of the thyroidis a disease in which cancer (malignant) cells are found in the tissuesof the thyroid gland. The thyroid gland is at the base of the throat.It has two lobes, one on the right side and one on the left. Thethyroid gland makes important hormones that help the body functionnormally.Cancer of the thyroid is more common in women than in men. Mostpatients are between 25 and 65 years old. People who have been exposedto large amounts of radiation, or who have had radiation treatment formedical problems in the head and neck have a higher chance of gettingthyroid cancer. The cancer may not occur until 20 years or longer afterthe initial radiation treatment.

A doctor should be seen if there is a lump or swelling in the front ofthe neck or in other parts of the neck. If there are symptoms, a doctorwill feel the patient's thyroid and check for lumps in the neck. Thedoctor may order blood tests and special scans to see whether a lump inthe thyroid is making too many hormones. Depending on test results andindividual risk factors. The doctor may want to take a small amount oftissue from the thyroid. This is called a biopsy. To do this, a smallneedle is inserted into the thyroid at the base of the throat and sometissue is drawn out. The tissue is then looked at under a microscope tosee whether it contains cancer.There are four main types of cancer of the thyroid (based on how thecancer cells look under a microscope): papillary, follicular,medullary, and anaplastic. The chance of recovery (prognosis) dependson the type of thyroid cancer, whether it is just in the thyroid or hasspread to other parts of the body (stage), and the patient's age andoverall health. Some types of thyroid cancer grow much faster thanothers.The genes in our cells carry the hereditary information from ourparents. An abnormal gene has been found in patients with some forms ofthyroid cancer. If medullary thyroid cancer is found, the patient mayhave been born with a certain abnormal gene which may have led to thecancer. Family members may have also inherited this abnormal gene.Tests have been developed to determine who has the genetic defect longbefore any cancer appears. It is important that the patient and his orher family members (children, grandchildren, parents, brothers,sisters, nieces and nephews) see a doctor about tests that will show ifthe abnormal gene is present. These tests are confidential and can helpthe doctor help patients. Family members, including young children, whodon't have cancer, but do have this abnormal gene, may reduce thechance of developing medullary thyroid cancer by having surgery tosafely remove the thyroid gland (thyroidectomy).Key Points Summary :

• Thyroid cancer is the most common endocrine cancer.
• Thyroid cancer is a cancerous tumor or growth located within the thyroid gland.
• Thyroid cancer is one of the few cancers that has increased in incidence rates over the past several years.

Thereare expected to be 11% more new cases in 2008 than in 2007 in theUnited States. The American Cancer Society estimates that there will beabout 37,340 new cases of thyroid cancer in the U.S. in 2008. Of thesenew cases, about 28,410 will occur in women and about 8,930 will occurin men. About 1,590 people (910 women and 680 men) will die of thyroidcancer in 2008.

Many patients, especially in the early stages of thyroid cancer, do notexperience symptoms. However, as the cancer develops, symptoms caninclude a lump or nodule in the front of the neck, hoarseness ordifficulty peaking, swollen lymph nodes, difficulty swallowing orbreathing, and pain in the throat or neck.There are several types of thyroid cancer: papillary, follicular,medullary, anaplastic, and variants.Papillary and follicular thyroid carcinomas~~Referred to as well-differentiated thyroid cancer and account for80–90% of all thyroid cancers. Variants include tall cell, insular,columnar, and Hurthle cell. Their treatment and management are similar.If detected early, most papillary and follicularthyroid cancer can betreated successfully. Medullary thyroid carcinoma (MTC) ~~

Accountsfor 5-10% of all thyroid cancers. Medullary cancer is easier to treatand control if found before it spreads to other parts of the body.There are two types of medullary thyroid cancer: sporadic and familial.Genetic testing (of the RET protooncogene should be performed in allpatients with MTC to determine whether there are genetic changes thatpredict the development of MTC. In individuals with these geneticchanges, removal of the thyroid during childhood has a high probabilityof being curative. Anaplastic thyroid carcinoma ~~ The leastcommon and accounts for only 1–2% of all thyroid cancer. This type isdifficult to control and treat because it is a very aggressive type ofthyroid cancer. Treatments for thyroid cancer include surgery,radioactive iodine treatment, external beam radiation therapy, andchemotherapy. In most cases, patients undergo surgery to remove most ofthe thyroid gland, and are treated with thyroid hormone replacementtherapy. For those with papillary and follicular thyroid cancer, thedose of thyroid hormone replacement is usually high enough to suppressthyroid stimulating hormone (TSH) well below the range that is normalfor someone not diagnosed with thyroid cancer, to help prevent thegrowth of cancer cells while providing essential thyroid hormone to thebody.Factors associated with thyroid cancer include a family history ofthyroid cancer, gender (women have a higher incidence of thyroidcancer), age (the majority of cases occur in people over 40, althoughthyroid cancer affects all age groups from children through seniors),and prior exposure of the thyroid gland to radiation.While the prognosis for most thyroid cancer patients is very good, therate of recurrence can be up to 30%, and recurrences can occur evendecades after the initial diagnosis. Therefore, it is important thatpatients get regular follow-up examinations to detect whether thecancer has re-emerged. Monitoring should continue throughout thepatient’s lifetime.Periodic follow-up examinations can include a review of the medicalhistory together with selected blood tests appropriate for the type ofcancer and stage of treatment (TSH, thyroglobulin, CEA, and calcitoninlevels), physical examination, and imaging techniques (ultrasound,radioiodine whole body scan, chest X-ray, CT, MRI, PET, and othertests).Metatastic Thyroid Cancer (spread to distant locations)Theguidelines cover diagnosis, surgery, staging, radioiodine ablation,post-therapy scans, TSH suppression, thyroglobulin testing, ultrasound,RAI scans, other imaging techniques, metastatic disease, and many othertopics. The thyroid cancer specialist physicians who developed theguidelines included many ThyCa medical advisors and conference andworkshop speakers.