Thyroid+Gland

In papillary and follicular carcinomas of the thyroid, three main trends seem to emerge.2 Oncocytic carcinomas (also known as Hürthle cell carcinomas) behave as a slightly more aggressive form of follicular cancer, but both present similarly.2 Medullary thyroid carcinomas tend to present in the earlier years of life for familiar disease and later for sporadic disease. Anaplastic or undifferentiated thyroid carcinoma, which is rare, afflicts those in the later decades of life. 2 || The endodermally derived follicular cell gives rise to papillary, follicular, and probably anaplastic carcinomas.3 The neuroendocrine-derived calcitonin-producing C cell gives rise to MTCs.3 Thyroid lymphomas arise from intrathyroid lymphoid tissue, whereas sarcomas likely arise from connective tissue in the thyroid gland.3 Radiation exposure significantly increases the risk for thyroid malignancies, particularly papillary thyroid carcinoma. 3 Low dietary intake of iodine does not increase the incidence of thyroid cancers overall. However, populations with low dietary iodine intake have a high proportion of follicular and anaplastic carcinomas.3 Thyroid cancer occurs when cells in your thyroid undergo genetic changes (mutations). The mutations allow the cells to grow and multiply rapidly.1 The cells also lose the ability to die, as normal cells would.1 The accumulating abnormal thyroid cells form a tumor, the abnormal cells can invade nearby tissue and can spread throughout the body.1 Chronic elevations of TSH levels may increase the incidence of differentiated thyroid carcinoma.2 || Most people with thyroid cancer have a palpable neck mass, which is often detected during a routine physical examination. Almost 25% of young people with differentiated thyroid carcinoma present because of a palpable cervical lymph node metastasis as a result of occult primary thyroid cancer.4
 * **Epidemiolgy:** || * Exposure to high levels of radiation. Examples of high levels of radiation include those that come from radiation treatment to the head and neck and from fallout from such sources as nuclear power plant accidents or weapons testing.1
 * Personal or family history of goiter. Goiter is a noncancerous enlargement of the thyroid.1
 * Certain inherited genetic syndromes. Genetic syndromes that increase the risk of thyroid cancer include familial medullary thyroid cancer, multiple endocrine neoplasia and familial adenomatous polyposis.1
 * The incidence in women is greater that in me by a factor of 2.5.
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Whites and Asians seem to be overrepresented in most case studies.
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">And the median age at diagnosis is earlier for papillary carcinoma than follicular.
 * **Etiology:** || <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Thyroid carcinomas arise from the 2 cell types present in the thyroid gland.3
 * **Signs & Symptoms:** || <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Thyroid cancer typically doesn't cause any signs or symptoms early in the disease. As thyroid cancer grows, it may cause:1 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">A lump that can be felt through the skin on your neck
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Changes to your voice, including increasing hoarseness
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Difficulty swallowing
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Pain in your neck and throat
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Swollen lymph nodes in your neck
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Lesions in the thyroid gland should arouse suspicion if they exhibit extreme hardness, appear to be fixed to deep structures or skin, and are associated with recurrent laryngeal nerve paralysis (hoarseness).
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Anaplastic carcinomas are usually large, hard, and fixed; grow rapidly; and occur in older patients. Patients can appear with symptoms related to compression and/or invasion of the esophagus, airway, or recurrent laryngeal nerves. Symptoms include pain, dysphagia, dyspnea, stridor and hoarseness.
 * <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Most patients with medullary carcinoma initally have an asymptomatic painless mass. They may appear with systemic symptoms of diarrhea related to vasoactive substances (calcitonin) produced by the tumor. This usually represents an advanced stage of the disease. ||
 * **Diagnostic Procedures:** || Fine needle aspiration (FNA) is the initial diagnostic tool used to discern malignancy. FNA, compared with blood tests and radiographs, has 98% sensitivity, 98% specificity, and 98% accuracy. Results read as benign, suspicious, malignant, or unsatisfactory/indeterminate. A negative FNA still requires careful thought before a repeat FNA or an excisional biopsy is ordered. FNA's best results require at least 3 nodules. After a negative FNA radionuclide imaging may be ordered. These nuclear medicine tests utilize I-131, I-125, I-123, or Tc- 99. Standard x-rays will show intraglandular calcifications in thyroid nodes. Blood chemistry to confirm or deny presence of cancer are T3, T4, TSH, Thyroglobin, and serum calcitonin level (for medullary thyroid cancer).7 ||
 * **Histology:** || Papillary thyroid CA:
 * 33-73% of all malignant thyroid tissue
 * Slow-growing
 * age range=30 to 50 yrs old
 * women to men 3:1 incidence

Follicular thyroid CA:
 * 14-33% of all malignant thyroid tissue
 * age range=50-58 yrs old
 * women to men 3:1 incidence

Medullary thyroid CA: Anaplastic thyroid CA: Frequently: to the cervical nodes, less frequent to anterior mediastinal nodes (except in anaplastic thyroid CA) occasionally to supraclavicular and retropharyngeal nodes.8 ||
 * 5-10% of all malignant thyroid tissue
 * 10% of all malignant thyroid tissue
 * age range=40-90 years
 * no gender preference ||
 * **Lymph node drainage:** || First: to the central compartment of the thyroid nodes in the tracheo- esophageal groove, and to the Delphin nodes (anterior to the larynx, just above the isthmus).
 * **Metastatic spread:** || Metastatic spread occurs by hematogenous routes - for example to the lungs and bones - but many other sites may be involved.5

Papillary Thyroid Carcinoma6 Follicular Thyroid Carcinoma6 Medullary Thyroid Carcinoma6
 * Metastisizes via lymphatic invasion; vascular invasion is uncommon.
 * Metastisizes at a late stage to the lungs and bones via a vascular route and may occur late.
 * Distant metastises typically occur late in the disease and usually involve the lungs, liver, bones, and adrenal glands.

Anaplastic Thyroid Carcinoma6 Papillary Thyroid Carcinoma 6 Follicular Thyroid Carcinoma 6 Medullary Thyroid Carcinoma 6 Anaplastic Thyroid Carcinoma 6 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">All categories may be subdivided: (a) solitary tumor, (b) multifocal tumor (the largest determines the classification). <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">TX - Primary tumor cannot be assessed <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T0 - No evidence of primary tumor <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T1 - Tumor 2 cm or less in greatest dimension limited to the thyroid <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T2 - Tumor more than 2 cm but not more than 4 cm in greatest dimension limited to the thyroid <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T3 - Tumor more than 4 cm in greatest dimension limited to the thyroid or any tumor with minimal extrathyroid extension (e.g., extension to sternothyroid muscle or perithyroid soft tissues). <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4a - Tumor of any size extending beyond the thyroid capsule to invade subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve. <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4b - Tumor invades prevertebral fascia or encases carotid artery or mediastinal vessels <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">All anaplastic carcinomas are considered T4 tumors. <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4a - Intrathyroidal anaplastic carcinoma—surgically resectable <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4b - Extrathyroidal anaplastic carcinoma—surgically unresectable <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Regional lymph nodes are the central compartment, lateral cervical, and upper mediastinal lymph nodes. <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">NX - Regional lymph nodes cannot be assessed <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">N0 - No regional lymph node metastasis <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">N1 - Regional lymph node metastasis <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">N1a - Metastasis to Level VI (pretracheal, paratracheal, and prelaryngeal/Delphian lymph nodes) <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">N1b - Metastasis to unilateral, bilateral, or contralateral cervical or superior mediastinal lymph nodes <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">MX - Distant metastasis cannot be assessed <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">M0 - No distant metastasis <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">M1 - Distant metastasis <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Separate stage groupings are recommended for papillary or follicular, <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">medullary, and anaplastic (undifferentiated) carcinoma. <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage I - Any T Any N M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage II - Any T Any N Ml <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage I - T1 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage II - T2 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage III - T3 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T1 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T2 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T3 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVA - T4a N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4a N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T1 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T2 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T3 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVB - T4b Any N M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVC - Any T Any N M1 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage I - T1 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage II - T2 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage III - T3 N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T1 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T2 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T3 N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVA - T4a N0 M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4a N1a M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T1 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T2 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T3 N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">T4a N1b M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVB - T4b Any N M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVC - Any T Any N M1 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVA - T4a Any N M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVB - T4b Any N M0 <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Stage IVC - Any T Any N M1 ||
 * Typically involves lymphovascular invasion and regional or distant spread at diagnosis. ||
 * **Grading:** || Histologic grade and age of the patient are of such importance in the behavior and prognosis of thyroid cancer that these factors are included in the TNM staging system. 5
 * Thyroid Carcinomas **
 * Most common subtype of thyroid carcinomas (60% to 75%).
 * Is well differentiated.
 * Tends to be unilateral, but may be unifocal within a lobe.
 * Is well differentiated.
 * Affects a slightly older patient population that does papillary thyroid carcinoma.
 * Neuroendocrine tumor of the parafolilcular cells.
 * 3% to 5% of all thyroid carcinomas.
 * Most cases are sporadic and tend to be solitary, whereas familial tumors tend to be bilateral and multifocal
 * 2% to 5% of all thyorid cancers; up to 50% of patients will have either antecedent or concurrent history of a well-differentiated thyorid carcinoma,
 * High grade tumor. ||
 * **Staging:** || **<span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Thyroid Cancer Staging **<span style="color: #800080; font-family: Arial,Helvetica,sans-serif; vertical-align: super;">5
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Primary Tumor (T) **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Regional Lymph Nodes (N) **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Distant Metastasis (M) **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">STAGE GROUPING **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Papillary or Follicular **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Under 45 years **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Papillary or Follicular **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">45 years and older **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Medullary Carcinoma **
 * <span style="color: #800080; font-family: Arial,Helvetica,sans-serif;">Anaplastic Carcinoma **
 * **Radiation side effects:** || effects Side effects include inflammation of salivary glands, nausea, vomiting, fatigue, and after repeated treatments bone marrow suppression can begin to occur. ||
 * **Prognosis:** || lesions demonstrating capsular invasion have a worse prognosis than those confined to the gland. Prognosis increases as the cells become more differentiated. Other factors that affect prognosis include age, gender, histologic subtype, and capsular invasion. ||
 * **Treatments:** || Surgery is the primary treatment of choice when dealing with tumors of the thyroid, if the tumor is encapsulated. For tumors that are not, surgery plus either Iodine treatments or radiation and chemotherapy are used. Radiation treatments are difficult due to the high dose needed for gross disease (in some cases up to 70 Gy may be used). Fields could include the gland, neck and superior mediastinum, and its common to take advantage of the benefits that IMRT can provide. Immobilization of the head and neck area is important in order to reduce movement. ||
 * **TD 5/5:** || thyroid gland TD 5/5 is 45 Gy ||
 * **References:** || # <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Thyroid Cancer. Mayo Clinic. Available at: <span style="font-family: Arial,Helvetica,sans-serif;">[] <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">. Accessed May 27, 2012.
 * 1) <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Lenhard RE, Osteen RT, Gansler T. The American Cancer Society's Clinical Oncology. 1st edition. Atlanta, GA: The American Cancer Society, Inc. 2001: 633-634, 637, 642.
 * 2) <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Thyroid Cancer. Medscape Reference. Available at: <span style="font-family: Arial,Helvetica,sans-serif;">[|http://emedicine.medscape.com/article/851968-overview#a1] <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">. Accessed May 27, 2012.
 * 3) <span style="color: #0000ff; font-family: Arial,Helvetica,sans-serif;">Washington CM, Leaver DT. //Principles and Practices of Radiation Oncology//. 3rd ed. St. Louis Mo: Mosby Elsevier; 104-106.159.
 * 4) American Joint Committee on Cancer. //AJCC Cancer Staging Manual//. 6th ed. New York, NY: Springer; 2002.
 * 5) Abraham J, Allegra CJ, Gulley J. //Bethesda Handbook of Clinical Oncology//. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
 * 6) Chao KSC, Perez CA, Brady LW. //Radiation Oncology Management Decisions//. 2nd Edition. Philadelphia PA. Lippincott Williams & Wilkins. 2002: 295 -301.
 * 7) Hansen. Roach. //Handbook of Evidence-Based Radiation Oncology//. 2nd Edition. New York, NY. Springer. 2010: 177 -179. ||

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