Introduction
The thyroid is a small butterfly-shaped gland that is situated in the lower front section of the neck. The main role of the thyroid gland is to control metabolism through the release of various hormones that direct energy utilisation and heat production (Fagin & Wells 2016). The thyroid gland is also responsible for maintenance of the heart rate, blood pressure and body weight. Thyroid cancer is a malignancy that occurs following the aberrant growth of cells that make up the thyroid gland.
The common indications of the disorder include the presence of a lump that can be sensed by touching the skin on the neck, alterations in voice production, hoarseness, problems swallowing, enlarged lymph nodes and pain in the neck area (Perros et al. 2014). Fortunately, thyroid cancer can be treated if diagnosed promptly. This dissertation proposal explores thyroid cancer chemotherapies. A literature review and background information of thyroid cancer chemotherapies is also provided together with the specific aim, hypothesis, proposed method and obtained laboratory competencies.
Literature Review and Background Information of Project Area
There are five different forms of thyroid cancer: papillary, follicular, medullary, anaplastic and thyroid lymphoma. Papillary thyroid cancer occurs more frequently than other thyroid malignancies. It develops from follicular cells whose role is to secrete and store thyroid hormones. This type of cancer is common in people aged 30 to 50 years (Davies & Welch, 2014). The origin of follicular thyroid cancer is the follicular cells.
However, it is often prevalent in people who are 50 years or older. A more belligerent sub-type of follicular thyroid cancer known as Hurthle cell cancer may occur (Grani et al. 2017). Medullary thyroid cancer, conversely, affects specific types of thyroid cells, referred to as C cells. The function of the C cells is to secrete the hormone calcitonin, which plays a role in calcium ion regulation. High blood concentration of calcitonin is an indication of medullary thyroid cancer, which may manifest in younger people (Brutsaert et al. 2015).
Anaplastic thyroid cancer develops in people aged 60 years and above. It is an atypical kind of thyroid tumour that poses difficulties during treatment. Thyroid lymphoma develops in the cells of the immune system situated in the thyroid gland. The resultant cancerous cells often multiply rapidly. This form of cancer is also prevalent in older adults.
Several factors increase one’s risk of thyroid cancer. The different types of thyroid cancer indicate that age increases an individual’s susceptibility to the disease. Older people are prone to developing thyroid cancer compared to their younger counterparts. Females are highly predisposed to thyroid cancer than males (Siegel, Miller & Jemal 2017). Contact with high levels of radiation through occupational processes and radiation treatment may also elevate the risk of thyroid cancer. A number of heritable genetic syndromes have also been implicated in the development of thyroid cancer. They include multiple endocrine neoplasias and familial medullary thyroid cancer (Krampitz & Norton 2014).
Various treatment options are available for thyroid cancer. However, the choice of treatment is determined by the type of cancer and its extent (level of progression), maturity, health standing and other unique attributes. Surgery is the most widespread treatment approach for thyroid cancer. It entails the partial or complete removal of the thyroid gland. Partial removal of the thyroid gland is known as lobectomy, whereas the complete removal of the gland is known as a thyroidectomy (Adam et al. 2014). Surgical intervention may also involve the removal of the lymph nodes in the neck region and other tissue surrounding the thyroid gland. The specific procedure is influenced by the magnitude and size of the tumour.
Radioactive iodine ablation is often used as a follow-up treatment to destroy any residual thyroid tissue following a thyroidectomy. Its effectiveness is attributed to the ability of thyroid gland and thyroid tumours to take in iodine. The radiations contained in the radioactive iodine then eradicate these issues. This treatment approach is also used for recurrent malignancies or cancer that has metastasised to adjacent lymph nodes and body organs. A prerequisite for this treatment is a special low-iodine diet for 7 to 14 days before treatment or abstinence from thyroid hormone pills.
The complete removal of the thyroid gland warrants the intake of thyroid hormone pills in what is known as thyroid hormone therapy (Stott et al. 2017). The pills also prevent the growth of residual cells by reducing the quantities of thyroid-stimulating hormone. Another form of treatment is external beam radiation, which is also known as X-ray therapy. Here, external radiations are used to get rid of cancer cells. However, it is important to protect the rest of the body from the radiations. The patient needs to undergo this treatment for several weeks. A recent approach to thyroid cancer treatment is targeted therapy where pharmacological agents that aim at specific parts of cancer cells are administered in pill form. Targeted therapy is linked with fewer side effects compared to chemotherapy.
Chemotherapy entails the use of chemical agents to kill malignant cells, which often divide rapidly. The drugs may be administered orally as pills, injected or given intravenously. Chemotherapy is a systemic treatment method, which means that the drugs traverse the circulatory system to reach other parts of the body apart from the cancer cells. Since the drugs target rapidly dividing cells, other tissues such as bone marrow cells, hair follicles and cells that line the gastrointestinal tract are also affected.
Consequently, chemotherapy is linked with several side effects such as mouth sores, hair loss, poor appetite, queasiness and vomiting, diarrhoea, increased predisposition to infections, easy bleeding and unusual fatigue (Carr, Vissers & Cook 2014). The last three side effects are associated with a decrease in leukocytes, platelets and erythrocytes, respectively. The range and magnitude of side effects are dependent on the specific drug used, treatment duration and mode of administration.
Chemotherapy is rarely used in the treatment of thyroid cancer because it is not often beneficial for most types of thyroid cancer. However, it is sometimes used alongside external beam radiation therapy in the treatment of anaplastic cancer. It may also be used in advanced thyroid cancer that is unresponsive to other treatment modalities. The most commonly used chemotherapeutic agents in thyroid cancer are doxorubicin and cisplatin (Yang et al. 2016). Before initiating chemotherapy, the medical provider should perform blood tests to ensure that the treatment is safe. It is also imperative to perform blood tests at each chemotherapy session.
Furthermore, some side effects associated with chemotherapy may require close observation. For instance, doxorubicin is reported to affect cardiac function in patients (Plana et al. 2014). Therefore, patients on this treatment may require repeated cardiac function tests such as echocardiograms (Murtagh et al. 2016).
Aim and Hypothesis of the Research
Aim
The aim of this dissertation is to discuss the treatment options for thyroid cancer. The types of thyroid cancers that will be addressed will range from nonresponsive or late discovered cancer that needs lobectomy or thyroidectomy to early diagnosed cancer that responds to chemotherapy. The dissertation will also explore the available drugs for the treatment of thyroid cancer, new technologies in this field as well as new drugs.
Hypothesis
It is hypothesised that chemotherapy is an effective treatment modality for all stages of thyroid cancer.
Proposed Research Plan and Methodology
The first step in the writing of the dissertation will be to conduct a thorough literature search to find relevant articles related to the research topic. The main keywords that will guide the search will include thyroid cancer, chemotherapy, lobectomy and thyroidectomy. Databases that will be used for the literature search include PubMed, EBSCOhost, CINAHL and Google Scholar. The search will be restricted to articles published within the last five years to ensure that the findings are up to date. Thereafter, relevant articles will be identified by skimming through the titles and reading through the abstracts, which will be followed by retrieving the full-text articles.
Pertinent information from the articles will be recorded in a literature review matrix table to facilitate the systematic recording of data. The table will include vital information such as citation details, type of study, thyroid cancer treatment approach, findings, conclusions, implications for clinical practice and level of evidence. The findings from the literature review matrix will then be used to compile the dissertation.
Competency Sessions Completed
The laboratory experience has enhanced the author’s competency in eight main areas: autoclave training and use of laboratory instruments, ethics, COSHH and RA competencies, bioanalytical methods, literature searching, bioinformatics, cell culture biology, molecular biology restriction analysis and electrophoresis. Literature searching competencies have been helpful in the identification of this research problem as well as finding relevant information to explain the background of the research.
These skills will also be useful in finding relevant literature for the writing of the dissertation. Knowledge of laboratory techniques such as cell culture biology, molecular biology restriction analysis, electrophoresis, autoclaving and use of laboratory instruments will facilitate the understanding and interpretation of scientific articles describing different treatment methods for thyroid cancer.
References
Adam, MA, Pura, J, Gu, L, Dinan, MA, Tyler, DS, Reed, SD, Roman, SA & Sosa, JA 2014, ‘Extent of surgery for papillary thyroid cancer is not associated with survival: an analysis of 61,775 patients’, Annals of Surgery, vol. 260, no. 4, pp. 601-605.
Brutsaert, EF, Gersten, AJ, Tassler, AB & Surks, MI 2015, ‘Medullary thyroid cancer with undetectable serum calcitonin’, The Journal of Clinical Endocrinology & Metabolism, vol. 100, no. 2, pp. 337-341.
Carr, AC, Vissers, MC & Cook, J 2014, ‘Relief from cancer chemotherapy side effects with pharmacologic vitamin C’, New Zealand Medical Journal, vol. 127, no. 1388, pp. 66-70.
Davies, L & Welch, HG 2014, ‘Current thyroid cancer trends in the United States’, JAMA Otolaryngology–Head & Neck Surgery, vol. 140, no. 4, pp. 317-322.
Fagin, JA & Wells Jr, SA 2016, ‘Biologic and clinical perspectives on thyroid cancer’, New England Journal of Medicine, vol. 375, no. 11, pp. 1054-1067.
Grani, G, Lamartina, L, Durante, C, Filetti, S & Cooper, DS 2017, ‘Follicular thyroid cancer and Hürthle cell carcinoma: challenges in diagnosis, treatment, and clinical management’, The Lancet Diabetes & Endocrinology, vol. 6 no. 6, pp. 500-514.
Krampitz, GW & Norton, JA 2014, ‘RET gene mutations (genotype and phenotype) of multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma’, Cancer, vol. 120, no. 13, pp. 1920-1931.
Murtagh, G, Lyons, T, O’Connell, E, Ballot, J, Geraghty, L, Fennelly, D, Gullo, G, Ledwidge, M, Crown, J, Gallagher, J & Watson, C 2016, ‘Late cardiac effects of chemotherapy in breast cancer survivors treated with adjuvant doxorubicin: 10-year follow-up’, Breast Cancer Research and Treatment, vol. 156, no. 3, pp. 501-506.
Perros, P, Boelaert, K, Colley, S, Evans, C, Evans, RM, Gerrard BA, G, Gilbert, J, Harrison, B, Johnson, SJ, Giles, TE & Moss, L 2014, ‘Guidelines for the management of thyroid cancer’, Clinical Endocrinology, vol. 81, Suppl 1, pp. 1-122.
Plana, JC, Galderisi, M, Barac, A, Ewer, MS, Ky, B, Scherrer-Crosbie, M, Ganame, J, Sebag, IA, Agler, DA, Badano, LP & Banchs, J 2014, ‘Expert consensus for multimodality imaging evaluation of adult patients during and after cancer therapy: a report from the American Society of Echocardiography and the European Association of Cardiovascular Imaging’, European Heart Journal–Cardiovascular Imaging, vol. 15, no. 10, pp. 1063-1093.
Siegel, RL, Miller, KD & Jemal, A 2017, ‘Cancer statistics, 2017’, CA: A Cancer Journal for Clinicians, vol. 67, no. 1, pp. 7-30.
Stott, DJ, Rodondi, N, Kearney, PM, Ford, I, Westendorp, RG, Mooijaart, SP, Sattar, N, Aubert, CE, Aujesky, D, Bauer, DC & Baumgartner, C 2017, ‘Thyroid hormone therapy for older adults with subclinical hypothyroidism’, New England Journal of Medicine, vol. 376, no. 26, pp. 2534-2544.
Yang, H, Chen, Z, Wu, M, Lei, T, Yu, H & Ge, M 2016, ‘Remarkable response in 2 cases of advanced poorly differentiated thyroid carcinoma with liposomal doxorubicin plus cisplatin’, Cancer Biology & Therapy, vol. 17, no. 6, pp. pp. 693-697.