Therapeutics of Colon Cancer - Coursework Example

AR Colon Cancer 5/11 Colon Cancer Introduction With the increase in the diagnostic power of diseases and disorders it is noticed thatmany of the diseases and disorders which were previously unknown have become known to the whole world. Colon Cancer (Colo-Rectal Cancer) is the cancer of large intestine which is characterized by previously existing polyposis syndromes. It is seen that the death rates of colon cancer are highest in the United States of America. The high incidence rate of colon cancer in United States is linked to the dietary practices of the population there. This is because it is found that even the migrants from other countries who are living in United States are suffering from the same problem because of the adoption of the same lifestyle as practiced in America (Robbins et al 2005; Jemel et al 2002). Risk Factors for Colon Cancer Some studies have also shown that obesity and inactivity of muscles can also lead to colon cancer. It is known that the incidence of colon cancer is also increased by several other predisposing factors. Dietary intake is one of the factors which can increase the incidence of colon cancer. It is advised that excess calories should not be consumed if they have already reached the requirements of the body (Wei et al 2004; Lieberman et al 2003; Robbins et al 2005). Low unabsorbable vegetable contents in the body can also lead to the cancer. This is because if these fibers are not present in the body then the stool would not be bulky enough to be excreted out in a small span of time. Thus the stool would take longer to be excreted and because of this it may alter the bacterial flora in the intestine leading to the cancer. A diet which contains red meat and refined carbohydrates is also known to be a risk factor for colon cancer. The byproducts of carbohydrates are toxic in nature and if they remain for much long time in the bowel they may yet alter the mucosa or bacterial flora which will again lead to cancer. And high cholesterol in red meat can lead to increased production of bile acids which can then be acted upon by bacteria and changed into potential carcinogens. And lastly low protective micronutrients in the diet can also lead to the cancer. All these risk factors together are leading to colon cancer and should be further researched upon to find alternative strategies for their prevention (Lieberman et al 2003; Robbins et al 2005). Chemotherapy Chemotherapy has proved to be a breakthrough in the cure of different cancers. Chemotherapy is basically associated with drugs which directly affect the metabolism of cells. These drugs act in collaboration together so that they can cause apoptosis of cancer cells and trigger deaths of unwanted cells which are causing the tumor to arise. These drugs associate their actions with the metabolism of cells by destroying or inhibiting their source of energy through which they can reproduce (Katzung 2004; Richard et al 2009). Chemotherapeutic Drugs used for Colon Cancer Colon Cancer is one of the most dangerous cancers which is cured through either a surgery or chemotherapy. Surgery at times does not prove to be beneficial in colon cancer as it has reached its late stages. And thus chemotherapy is considered to be the best option for individuals who are suffering from this kind of cancer. The chemotherapy drugs which are prescribed to patients suffering from this cancer are given in collaboration so that all of these drugs act together to produce the desired effect. The drugs which are widely used for the treatment are 5-Fluorouracil, Oxaliplatin, leucovorin, irinotecan, and capecitabine (Richard et al 2009; Rang et al 2007; Pratt et al 1990) 5-Fluorouracil Most of these drugs are given in combination with each other so that their effects are maximized. 5-Fluorouracil is known to be a first line chemotherapy drug for the cure of colon cancer. 5-FU is a pyrimidine analog which consists of a fluorine atom rather than a hydrogen atom at the position five of uracil ring.5-FU enters the cell through a carrier protein after which it is converted into 5-Fluorodeoxyuridine monophosphate. This 5-FdUMP then competes for the enzyme thymidylate synthase and reduces its activity. It forms a ternary complex with the enzyme because of which it cannot release products for the synthesis of DNA. It is because of this activity that thymidine is depleted in the cell and cell growth becomes impossible. This further leads to the death of the cell because of thymidine deficiency (Harvey et al 1994; Richard et al 2009; Katzung 2004). Leucovorin Leucovorin is a drug which is used in collaboration with 5-FU to increase its effectiveness. It is this leucovorin which helps to provide 5-FU with the reduced folate coenzyme. This coenzyme is required to inhibit the synthesis of thymidine by the cell and it also helps 5-FU to form a ternary complex so that thymidylate synthase can be inhibited (Richard et al 2009). Oxaloplatin Oxaloplatin which is another drug being used in collaboration with leucovorin and 5-FU is a diaminocyclohexane platinum analog. Oxaloplatin is believed to act as a killer drug for the cells as it inhibits the synthesis of DNA and binds DNA through strand cross linkages. These cross linkages are usually formed at N7 of guanine but at some other instances they are also found in between cytosine and adenine. It is used as the first and line of therapy for colo-rectal cancer (Richard et al 2009). Irinotecan Irinotecan is a derivative of an earlier drug camptothecin which is used as a first line therapy for colo-rectal cancer. It is given in collaboration with 5-FU and leucovorin. Irinotecan forms an active metabolite known as SN-38. The carbomate bond between the camptothecin moiety and the dipiperidino side chain is cleaved by carboxylesterase activity which forms the active metabolite. SN-38 then inhibits topoisomerase I because of which relegation of single strand breaks becomes impossible (Richard et al 2009). Capecitabine Capecitabine is another first line chemotherapeutic drug which is a fluoropyrimidine carbamate. It is considered to be the same as 5-FU except the fact that it is not in the raw form of 5-FU itself. It undergoes a series of reactions to form 5-FU itself. It is formed by the activity of thymidine phosphorylase which is found to be concentrated in conditions such as cancers. It has the same effect as that of 5-FU i.e. it helps in inhibiting thymidylate synthase and thus helps to reduce the concentration of thymidine in the cell (Richard et al 2009; Katzung 2004). New Researches for Colon Cancer With the high incidence rate of colo-rectal cancer it has become necessary for the health professionals to derive new resources which would help in curing the cancer. Two types of drugs have been recently found to be very helpful in curing colo-rectal cancer. These drugs act as antiangiogenesis agents which act on factors to decrease the blood flow to the cancerous cells. Two of the important drugs which being used as antiangiogenesis agents are Bevacizumab and Cetuximab (Richard et al 2009; National Cancer Bulletin 2009). Bevacizumab Bevacizumab is a chemotherapeutic drug which is also called an antiangiogenesis agent. It is classed as a monoclonal antibody which binds itself to vascular endothelial growth factor so that new blood vessels cannot be formed. With blood supply distorted to the cancerous cells it can be impossible for them to grow further as they would not be getting the necessary nutrients. It is used as both first and second drug line treatment (Richard et al 2009) Cetuximab Cetuximab is another monoclonic antibody that is used for the treatment of colon cancer. It acts by binding to the epidermal growth factor receptor which is found on the membranes of the cancer cells. After binding it causes difficulties or prevents the cancer cells totally from growing further. It can be given separately or in collaboration with irinotecan (Richard et al 2009). Recent researches on Colon Cancer A recent research cited in the bulletin of National Cancer Institute shows that it is better to give Bevacizumab alone rather than in combination with Cetuximab. The research found that if they are given in combination the effect of Bevacizumab would be decreased and the median survival rate of the patients would also be affected. Thus it is recommended that Bevacizumab is rather given alone rather than in collaboration with Cetuximab (NCI Cancer Bulletin 2009). Moreover researches have also been done on genes which induce colon cancer and the effects of these genes. These researches prove that some drugs would not be able to cure colon cancers which have distortions in the K-ras or BRAF genes. It is because of these researches that health professionals can now specifically test for genes and then start chemotherapy for a patient according to the changes in his genes. Further researches have also been done to find out how to prevent colo-rectal cancer to develop in a healthy individual. Some studies prove that folate, vitamin D and A can be helpful to prevent the risk of colon cancer. It is also believed that aspirin has a profound effect on the development of colon cancer. Consumption of aspirin is found to greatly reduce the risk of colon cancer in individuals as shown by different studies (Imperiale 2003 879-80; NCI Cancer Bulletin 2008). Conclusion New techniques for detecting colon cancer in its early stages have also been derived because of which colon cancer can be easily cured. It is believed that in its latter stages curing the colon cancer is very difficult. Colon Cancer is a widely prevalent disease in this world which is causing a number of deaths worldwide. It is important for the health professionals to derive new technologies and therapies for its cure (Robbins et al 2005; Richard et al 2009). Bibliography Top of Form Jemal, A., A. Thomas, T. Murray, and M. Thun. "Cancer Statistics, 2002." CA -ATLANTA-. 52 (2002): 23. Top of Form Wei, E. K., E. Giovannucci, K. Wu, B. Rosner, C. S. Fuchs, W. C. Willett, and G. A. Colditz. "Comparison of Risk Factors for Colon and Rectal Cancer."INTERNATIONAL JOURNAL OF CANCER. 108 (2004): 433-442. Top of Form Imperiale TF. "Aspirin and the Prevention of Colorectal Cancer." The New England Journal of Medicine. 348. 10 (2003): 879-80. Top of Form Lieberman, D A, S Prindiville, D G Weiss, and W Willett. "Risk Factors for Advanced Colonic Neoplasia and Hyperplastic Polyps in Asymptomatic Individuals."JAMA : the Journal of the American Medical Association. 290. 22 (2003): 2959. Bottom of Form Top of Form Kumar, Vinay, Abul K. Abbas, Nelson Fausto, Stanley L. Robbins, and Ramzi S. Cotran. Robbins and Cotran Pathologic Basis of Disease. Philadelphia: Elsevier Saunders, 2005. Bottom of Form Bottom of Form Bottom of Form Bottom of Form Top of Form Katzung, Bertram G. Basic & Clinical Pharmacology. New York: Lange Medical Books/McGraw Hill, 2004. Top of Form Rang, H. P. Rang and Dales Pharmacology. Philadelphia, PA: Churchill Livingstone/Elsevier, 2007. Top of Form Finkel, Richard, Michelle Alexia Clark, Luigi X. Cubeddu, Michael Cooper, Christopher T. Flatt, and Laura OLeary.Pharmacology: Lippincotts Illustrated Reviews. Philadelphia [etc.]: Lippincott Williams & Wilkins, 2009. Bottom of Form Top of Form Pratt, William B., Palmer Taylor, and Avram Goldstein.Principles of Drug Action: The Basis of Pharmacology. New York: Churchill Livingstone, 1990. Combining Targeted Drugs Is Worse in Colorectal Cancer. NCI Cancer Bulletin Vol 6 Feb 10 2009. Top of Form Champe, Pamela C., and Richard A. Harvey. Lippincotts Illustrated Reviews: Biochemistry. Lippincotts illustrated reviews. Philadelphia: Lippincott, 1994. Colorectal Cancer Trials Support Gene Testing for Two Drugs. NCI Cancer Bulletin Vol 5/No 22. Nov 4 2008. Bottom of Form Bottom of Form Bottom of Form Bottom of Form Read More