Please enjoy my beautifully composed analysis of thyroid cancer. If I were a teacher, I would make a new grade just for this paper and give it an A++, but that's just me. In lieu of pictures throughout the paper, you can view my also A++ worthy powerpoint that is fairly incoherent when I am not there talking and filling in the blanks, but knock yourself out.
Matt Pendo
2-13-11
Thyroid Cancer
Thyroid Cancer is cancer that occurs in the thyroid gland. Cancer of the thyroid was discovered slightly before the end of 19th century by Dr. William Stewart Halsted, an American surgeon who was also a cocaine and morphine addict. Thyroid cancers take up about 1% of all diagnosed cancers and the survival rates are generally very high, particularly if the cancer has not metastasized. (University of Texas Medical Branch) Thyroid cancer is fairly rare, and one out of every 111 people will be diagnosed with thyroid cancer over the course of their life. (National Cancer Institute) This is .9%, an extremely low number that shows just how uncommon thyroid cancer is. Although it is uncommon, every year around 25,000 women and 8,000 men learn that they have thyroid cancer. (NCI)
The thyroid gland is a butterfly shaped hormonal gland located just below the Adam’s apple that is wrapped around the windpipe and makes and stores hormones. These hormones regulate heart rate, metabolism, blood pressure, and growth. The thyroid uses iodine to make hormones that every cell in the body relies on. In particular, the hormones thyroxine (T4) and triiodinetyronine (T3), play a large role in the regulation of metabolism and are extremely important. Hormonal production of the thyroid is controlled by thyroid stimulating hormone (TSH) in feedback mechanism similar to the renal feedback mechanism. When levels of T3 and T4 become too low, the pituitary gland in the brain signals for TSH to be secreted and regulate the hormone levels. Conversely, if hormone levels are too high the pituitary gland secretes less TSH until the hormonal level is normal. Another hormone made by the thyroid is calcitonin. Calcitonin is made by the C cells of the thyroid rather than the follicular cells that make T3 and T4 and helps bone cells add calcium to the bone. Thyroid cancer affects the normal production of these hormones and can cause many problems if not treated.
There are four main types of thyroid cancer, and they are all carcinomas, meaning they all occur in tissue cells. The most common type of thyroid cancer is papillary carcinoma, which makes up around 80% of all thyroid cancer cases. This cancer occurs in the follicular cells and is usually very treatable if found before metastasis. The second most common form of thyroid cancer is follicular carcinoma, which also occurs in the follicular cells. This type of thyroid cancer accounts for about 15% of thyroid cancer cases and is also treatable if found early. The third most common variety of thyroid cancer is Medullary carcinoma, which occurs in the C cells of the thyroid and affects the levels of calcitonin. This variety makes up about 3% of all thyroid cancer diagnoses and is also treatable when found before it has metastasized. The final form of thyroid cancer and the most uncommon is anaplastic carcinoma. This form of thyroid cancer occurs in the follicular cells of the thyroid and only accounts for about 2% of all thyroid cancer cases. Although this is the most rare, it is the most deadly. Anaplastic carcinoma grows rapidly and is extremely difficult to control. All of these cancers form growths on the thyroid gland that are called nodules. These nodules are basically tumors on the thyroid, but only 10% of thyroid nodules are malignant.
Although thyroid cancer is a fairly uncommon form of cancer, there are several risk factors that can increase one’s chances of obtaining thyroid cancer. One of these risk factors is radiation, either from high dose x-rays or radioactive fallout. Dental x-rays from the first half of the 20th century along with association with nuclear weapons or energy puts one at an increased risk of getting thyroid cancer. Family history also plays a role in thyroid cancer. Growths on the colon or goiters can increase somebody’s chances of getting papillary carcinoma. Also, Medullary carcinoma can be passed down genetically. Specifically, a mutation in the RET gene can be passed down. Almost everyone who was born with this mutation gets Medullary carcinoma. In addition, females are three times more likely to get thyroid cancer than males. Studies are also being done to see if iodine levels are associated with thyroid cancer. Preliminary research hints that low iodine levels can cause follicular carcinoma and that high levels of iodine can cause papillary carcinoma. Finally, there is some research that suggests increased consumption of shellfish or seafood could be associated with thyroid cancer risk.
Cancers are caused by mutations in the cell cycle, and scientists have been able to pinpoint some of the exact mutations that cause thyroid cancer. As I mentioned before, Medullary carcinoma can be caused by the heredity of a mutated RET gene. Papillary carcinoma is usually caused by one of three genetic mutations. The mutation usually occurs in the RET gene, the BRAF gene, or the RAS gene. When radiation is not an associated factor, the mutation usually happens to the BRAF gene. The BRAF gene fuses with part of the AKAP9 gene and the combined gene stimulates normal cells to turn in to cancerous cells. In anaplastic carcinoma, the RhoB tumor suppressor gene stops functioning and a cancerous growth is the result. When radiation is associated, the mutation usually occurs in the RET gene. Although these cancers happen when the cell cycle functions improperly, there are several ways to treat thyroid cancers.
There are several treatment options for one who has thyroid cancer. One of the major treatment options is surgery. Two of the most common surgical procedures are a thyroidectomy or a lobectomy. In a thyroidectomy, the whole thyroid gland is removed. This removes the nodule, but without a thyroid pills will have to be taken for the rest of one’s life in order to regulate hormone levels. A lobectomy is a procedure sometimes used on patients with follicular or papillary thyroid cancer and only part of the thyroid is removed. Another treatment option is thyroid hormone treatment. These are usually pills that regulate blood pressure, heart rate, weight, and body temperature and are often prescribed after thyroid surgery. Another option is treatment with radioactive iodine. This is used on some patients with papillary or follicular thyroid cancer and consists of the patient consuming radioactive iodine which kills the thyroid cells, both cancerous and non cancerous. Yet another option is external radiation therapy. This is when radiation from outside of the body is concentrated at the affected area and is only used when surgery and radioactive iodine treatment cannot be used. For anaplastic thyroid cancer, the deadliest, chemotherapy is often used. In chemotherapy, the patient consumes radioactive medicine that kills cancerous cells. Another treatment for anaplastic thyroid cancer is a drug called RS5444. This drug activates the RhoB tumor suppressor that is dysfunctional in anaplastic thyroid cancer cells. Drugs that activate deactivated genes are rare, but this drug does exactly that. Although thyroid cancer is rare, there are many treatment options and survival rates are high.
When the cell cycle does not function correctly in the thyroid, cancerous nodules are sometimes the result. However, these cancerous nodules are often treatable. From treatments such as radioactive iodine therapy to RS5444, thyroid cancer has one of the highest survival rates. Even though it has a high survival rate, it is already an uncommon cancer. Ever since its discovery in the late 19th century, research has allowed most people with thyroid cancer to live normal lives after diagnosis.
Sources:
http://www.medterms.com/script/main/art.asp?articlekey=5778
http://www.endocrineweb.com/conditions/thyroid/how-your-thyroid-works
http://www.cancer.gov/cancertopics/types/thyroid
http://www.cancer.gov/cancertopics/wyntk/thyroid/page9
http://www.medindia.net/news/view_news_main.asp?x=3200
http://www.medindia.net/patients/patientinfo/thyroid-cancer-symptoms-risk.htm
http://www.medindia.net/news/New-Drug-To-Turn-On-Tumor-Supressor-Gene-In-Thyroid-Cancer-Cells-46631-1.htm
http://www.utmb.edu/otoref/grnds/thyroid-ca-021204/thyroid-ca-021204.htm
http://seer.cancer.gov/statfacts/html/thyro.html
Check out my powerpoint that won't make sense unless you read the paper.
As of right now, my knowledge on the human body is limited, and most of it is derived from random bits and pieces of info that have accumulated in my mind over the course of my life as well as a bits and pieces from watching the TV show, "Scrubs." First off, the human body is a system. It is an intricate piece of machinery that is made up of many smaller systems that must all work in tandem in order to run smoothly. When one metaphorical cog in the machine malfunctions, it can cause negative affects across the board. Some of these systems within the human body include the nervous (cue the puns), circulatory, digestive and respiratory systems, among others. The circulatory system is one's blood. Blood is critical in delivering oxygen and other nutrients to different areas of the body. Muscles, for instance, need oxygen to operate. Now where does the blood get this oxygen, the curious child asks, well let me tell you. The oxygen must come from outside of the body, and it gets inside via the respiratory system. The respiratory system revolves around the lungs. When one inhales, they breathe in oxygen, among other things, and this oxygen is then carried through the blood stream. This illustrates the intricate interconnectedness of the human body. Systems rely on systems, and if system doesn't fulfill its duty, the others suffer as a result. The human body is like a well oiled machine, and it needs to prevent malfunctioning. This is done by the immune system which strives to prevent disease or sickness from falling upon the body. Although I am aware that the human body is a metaphorical interdependent machine, I am not at all educated on the specifics of how exactly the systems work perfectly in tandem. In this next segment, I will simply list random facts about the body that I know, and I hope that charging headfirst at this unit, metaphorically of course, will help me understand how all of the different facets of the human body are able to perform together as one.