The Biology of Thyroid Cance - Essay Example

? CHARLES DARWIN BIOL 102, LAB SECTION 8 THE BIOLOGY OF THYROID CANCER Thyroid cancer is a disease condition of abnormal cells growth of thyroid gland. The thyroid gland is a butter-fly shaped gland located on the front segment of neck at the bottom of the throat. Thyroid gland possesses two lobes, left and right. Thyroid gland is an endocrine gland that produces hormone called as thyroid hormone, utilizing iodine in the process of synthesis. Thyroid hormone is known to regulate body metabolism and therefore plays a crucial role in the development process. Thyroid hormones are essential for the regulation of blood pressure, heart rate, metabolism and temperature of body, influences nervous system, muscular system and other systems as well. Regulation of the hormone produced by this gland may result in hyperthyroidism (Graves' Disease) or hypothyroidism. Thyroid cancer is considered as an uncommon type of cancer. Thyroid cancer is categorized into four groups encompassing papillary, medullary, follicular and anaplastic thyroid cancers. Lumps or masses grow in thyroid which are benign in ninety-five percent of cases. There is always a propensity that they may spread to other body parts if remain untreated (Web. "Thyroid Cancer", n.d.). Epidemiology The American Cancer Society reveals that around 17,200 cases of thyroid cancer appear each year, this number contributes to 1 percent of all the cancer cases prevalent in United States. Women are considered to be three times more prone to display the symptoms of thyroid cancer as compared to men. Problems related to thyroid hormone is common in teenagers, adolescents and younger individuals, but thyroid cancer is known to develop at the age of over 50 years (Web. "Thyroid Cancer", n.d.). Worldwide estimations reveal that more than 862,000 individuals diagnosed with thyroid cancer in 2003 were alive in 2008 (Web."Thyroid cancer incidence statistics", n.d.). Genetic-associated risk factors: chromosome(s)/gene(s) involved Genes are responsible for the metabolism of the organism, they control the functions of the cells. Cancers initially progress from the normal cells and gradually gain the potential to multiply unusually and ultimately become malignant. These malignant cells proliferate clonally and form tumors which in due course impend to turn metastatic. Cancer, also known as malignant neoplasm, the hallmark characteristic involves uncontrolled proliferation of cells. Under normal conditions cell grow, divide and die, but in cancer cells the defect takes place at the gene level leading to the formation of an abnormal DNA. As genes are the basic control machine of the cell, alteration of any kind may bring devastating consequences, or malignancy. Autosomal dominance inheritance of mutated gene (only single cope) could lead to thyroid cancer, although its prevalence is only 1 percent. The inheritance of defective gene could be estimated with genetic testing. Medullary thyroid cancer (MTC) contributes to 5 percent of thyroid cancers. Genetic conditions playing role in inheritance of MTC are multiple endocrine neoplasia (MEN) 2A, 2B as well as familial medullary thyroid carcinoma (FMTC). On the other hand, papillary and follicular thyroid cancers contribute to 90 percent of all thyroid cancers (Web. "The Genetics of Thyroid Cancer", 2011). Risk factors other than genetics Risk factors enhances the chance of developing cancer. In most of the cases, thyroid cancers are sporadic. About 10 percent of the thyroid cancers are inherited (5 percent papillary, and follicular, while 25 percent MTC). Other risk factors involve gender (women are more prone), age (2/3 of the cases are reported between 20 and 55 years), while anaplastic thyroid cancer is reported after 60 years of age. Radiation exposure (X-ray treatment to treat tonsillitis), exposure to radioactive iodine in childhood days enhance the chances of papillary and follicular thyroid cancers. Low iodine in diet may also cause thyroid cancer (Web. "Thyroid Cancer- Risk Factors", 2013). Symptoms Typical Thyroid cancer does not pose any symptoms. Gradually when the cancer grows it displays appearance of lump in neck, voice modulation, enhanced hoarseness, trouble while swallowing, pain in neck and throat, lymph nodes of neck region may become swollen (Web. "Thyroid cancer- Symptoms"). Diagnosis A lump in the neck growing quickly could be diagnosed for thyroid cancer by imaging tests, ultrasound (using transducer), radioiodine scan, chest x-ray, computed tomography (CT) scan, Magnetic resonance imaging (MRI) scan, Positron emission tomography (PET) scan could be used to diagnose thyroid cancer. Blood tests for thyroid-stimulating hormone (TSH), T3 and T4 (thyroid hormones) levels, thyroglobulin level, calcitonin level, carcinoembryonic antigen (CEA), vocal cord examination (laryngoscopy) are utilized for diagnosis (Web. "How is thyroid cancer diagnosed"). Therapy options before metastasis Cancer treatment is multidisciplinary. Treatment before metastasis stage i.e. beyond stage IV is done by surgery encompassing total thyroidectomy, near-total thyroidectomy, lobectomy, thyroid hormone treatment for papillary, medullary and follicular thyroid cancers, thyroid hormone replacement by levothyroxine, radioactive iodine therapy, chemotherapy and targeted therapy are some of the treatment measures. From stage I to stage IV, surgery, hormone therapy and other mentioned therapies work but beyond the stage IV thyroid cancer spreads and become metastatic (Web. "Thyroid cancer- Treatment"). Therapy options after metastasis Multiple tumors indicate that metastasis has occurred. The treatment of choice is then chemotherapy with a drug that prevents chromosomes from separating during mitosis (surgery and radiotherapy are not feasible options after metastasis of this disease). However, any cells that divide rapidly will be affected by this drug, not just the tumor cells. If the tumors do not respond, then the patient is offered palliative care also called hospice care. However, nursing care and special equipment make the life somewhat better and working easy (Web. "Thyroid cancer- Treatment"). Prognosis Five year relative survival rates are reported in individuals diagnosed with thyroid cancer. However, there is a stage related survival rate. In papillary thyroid cancer, stage I, II, III and IV has the survival rate of near 100% for I and II and 93 % for stage III and 51 % for stage IV. In follicular thyroid cancer stage I and II 5 year relative survival rate is near 100% whiole for stage II it is 71% and for stage IV it is 50%. For medullary thyroid cancer stage I is 100%, II is 98%, III is 81% and IV is 28%. For anaplastic thyroid cancer stage IV has the survival is around 7% (Web. "Thyroid cancer survival by type and stage") Information sources "How is thyroid cancer diagnosed". Web. 15 November 2013. . "The Genetics of Thyroid Cancer". Web. 15 November 2013. . 2011 "Thyroid Cancer". Web. 15 November 2013. . "Thyroid cancer incidence statistics". Web. 15 November 2013. . "Thyroid Cancer- Risk Factors". Web. 15 November 2013. . "Thyroid cancer- Symptoms" Web. 15 November 2013. . "Thyroid cancer- Treatment". Web. 15 November 2013. . "Thyroid cancer survival by type and stage". Web. 15 November 2013. . Read More