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  1. 1. Cancer 1Name:University:Course:Tutor:Date: CancerIntroduction Cancer is uncontrolled growth of a group of cells which invade and destroyadjacent tissues, and can move to other parts of the body. The abnormal cells are calledmalignant cells, cancer cells or tumor cells. There are more than a hundred types ofcancer and their classification is based on the type of cell that was attacked initially.Uncontrollable division of damaged cells harms the body when lumps or masses oftissues (tumors) are formed (Anand et al 2097). Tumors affect the normal systems of thebody such as circulatory, digestive and nervous systems, and produces hormones whichalter normal body function. Benign tumors are ones which demonstrate limitedmovement and growth. Malignant tumors are the most dangerous and they form when thefollowing happens: cancer cells move across the body through the blood or lymphsystems and destroy healthy tissue; and when a cell divides and forms blood vessels andfeeds itself through a process known angiogenesis (Kuper et al 460). A tumor can movesuccessfully to different parts of the body and grow, invade and destroy tissues which arehealthy. The tumor will be said to have metasized. This document will critically evaluatethe symptoms, causes, diagnosis, treatment and prevention of cancer. This paper willexplore the subject matter of cancer, with a close attention levied to malignant tumors
  2. 2. Cancer 2Symptoms and signs Symptoms of cancer are different and they depend on the location of cancer, thesize of the tumor and where it has spread. It is possible to see or feel cancer through theskin. For instance a lump on the testicle or breast may be a sign of cancer in these areas.It is possible to note skin cancer (melanoma) when a wart or a mole located on the skinchanges. In addition, Kinzler (134) says that some forms of oral cancers can make thetongue to have white spots or have white patches in the inside sections of the mouth.Symptoms of brain tumor tend to occur during the early stages of the disease sincecrucial cognitive functions will be affected. Cancer of the pancreas is often small for thesymptoms to be realized early. It is only realized when pain is felt after squeezing the nerves which are close oraffects the functions of the liver. This can make the eyes and skin to turn yellow, acondition known as jaundice. Moreover, as the tumor continues to grow, symptoms startto appear since body organs and blood vessels will be pushed by the tumor. For instance,symptoms relating to the cancer of the colon include diarrhea, constipation and changesin the size of stool (Mucci 480). Prostate or bladder cancer can affect the functions ofbladder by causing frequent or infrequent urination. Symptoms which can occur includeexcessive sweating, fast weight loss, fever, fatigue and anemia. Brenner et al (470) say that these symptoms are also common in other types ofproblems. For instance, hoarseness and coughing may indicate throat or lung cancer, orany other ailment. After cancer has metastasized, the affected area will produce othersymptoms. Enlarged or swollen lymph nodes can appear early in the disease. However, ifthe spread of cancer affects the brain, an individual is likely to experience seizure, vertigo
  3. 3. Cancer 3and headaches. When the lungs are affected, an individual will cough constantly andexperience shortness of brain. The liver tends to enlarge leading to jaundice while thebones are likely to be brittle, painful and break easily. Rheingold (213) says that thesymptoms of a metastasis will be determined ultimately by the areas which have beenaffected by the spread of cancer.Classification: Cancer has been classified into five broad categories. First, Carcinomasare cancers which start in the skin or tissues that cover internal organs. Since they arederived from epithelial cells, they cover both internal and external body parts such asbreast, lung, prostate and colon. Second, Sarcomas are cancers which start in the bone,muscle, cartilage, blood vessels, fats or other supportive or connective tissues. (Anand etal 2098) says that this group of cancer can also be derived from mesenchymal cells.Third, Lymphomas are cancers which begin in the immune system tissues and nymphnodes. This group of cancer is derived from hematopoietic cells. Fourth, Leukemia arecancers which start in the bone marrow and ultimately accumulate in the bloodstreamlastly, Adenomas are cancers which begin in the adrenal gland, pituitary gland, thyroid,and other glandular tissues.Diagnosis: When cancer is diagnosed in its early stages, successful treatment and cure isgreatly improved. Most cancers are recognized when signs and symptoms begin to appearor after screening (Panno 125). However, these methods still lack an exact diagnosis andan individual must visit a pathologist who will investigate the symptoms using medicaltests. Such tests include blood tests, endoscopy, X-rays and CT scans. All these are
  4. 4. Cancer 4imaging tests which detect the location of a tumor and the types of organs which havebeen affected.Pathology: To get a definitive pathology for several types of malignancies, a pathologisthas to carry out histological examination of cancer cells. Surgery or biopsy is used toobtain tissues. Skin, liver and breast biopsies can be done from a doctor’s office but othertissues require an operation under anesthesia. Diagnosis of a tissue indicates the nature ofa cell, genetic abnormalities, histological grade and different characteristics of the tumor(Brenner et al 474). Immunohistochemistry and Cytogenetics are forms of pathologicaltests which can also be performed on a tissue.Causes Research evidence indicates that 90 to 95 percent cases of cancer are caused byenvironmental factors while only 5 to 10 percent is attributed to genetics (Anand et al2097; World Health Organization). Cancer researchers say that the word environmentalrefers to all those causes not related to genetics. Some of the environmental causes whichare commonly attributed to cancer death include tobacco, infections, radiation, stress,obesity and diet, environmental pollutants and lack of physical activity. a. Chemicals: Carcinogens are DNA mutations which cause cancer and they arelinked to specific substances which lead to particular types of cancer. For instance,Samaras (270) says that 90 percent of lung cancer is caused by smoking tobacco.Smoking is also attributed to the cancer of the stomach, head, bladder, pancreas, kidney,neck, larynx, esophagus and stomach. Tobacco smoke has more than 50 carcinogenswhich includes polycyclic aromatic hydrocarbons and nitrosamines (Mucci 481). One inevery three cancer deaths in developed countries is attributed to tobacco while the rate is
  5. 5. Cancer 5one in every five across the world. 2-20% of cancer is believed to be related to theprofession of an individual. Across the world, close to 200,000 cancer deaths are reportedand they relate to occupational risk factors (Medical News Today). For instance, inhalingtobacco smoke and asbestos fibers can cause mesothelioma and lung cancer. Second,exposure to benzene outs workers at risk of developing leukemia. b. Diet and exercise: Cancer attributed to obesity, diet and lack of physicalactivity is close to 30-35%. Apart from contributing to 14-20% cancer deaths in the U.S.,HHH says that excessive body weight puts people at risk of developing other forms ofcancer. Physical inactivity puts an individual at risk of cancer not just because of thebody weight but other negative effects on the endocrine and immune system. Foodswhich cause cancer include red meat and diets low in fruits, whole grains and vegetables(Kinzler et al 135). High salt intake can cause gastric cancer, aflatoxin B1 causes livercancer, wile Betel chewing is attributed to oral cancer. c. Infection: Infectious diseases causes close to 18% cancers worldwide. This ratevaries from region to region with Africa recording the highest (25%) and the lowest indeveloped countries (10%) (Medical News Today). Viruses are the most commoninfectious agents with the ability to cause cancer but parasites and bacteria can also play arole. Oncovirus are those viruses which can cause cancer. Cancer of the cervix is causedby human papillomavirus while B-cell lymphoproliferative disease is caused Epstein-Barr virus. Kaposis sarcoma herpes virus is responsible for primary effusion lymphomaswhile hepatocellular carcinoma is caused by hepatitis B and hepatitis C viruses.Leukemia is caused Human T-cell leukemia virus-1. Gastric carcinoma is a cancer
  6. 6. Cancer 6attributed to bacteria infection. Moreover, parasitic infections which can cause cancerinclude liver flukes, schistosoma haematobium and Clonorchis sinensis. d. Radiation: Ionizing and non-ionizing radiation is responsible for 10% ofinvasive cancer. Non- melanoma skin cancers are non-invasive and they are caused bynon-ionizing ultraviolet radiation (Samaras 270). Evidence shows that radiation can causecancer in all animals and it may take up to forty years to be clinically manifested.Leukemia which has been induced by radiation takes 2-10 years to be manifested andstatistics show that children and teenagers are twice as like to be affected as adults. e. Heredity: Several case of cancer is non-hereditary and they are also knownsporadic cancers. Hereditary cancer is attributed to a genetic effect and statistics showthat there is around 0.3% carriers of the genetic mutation (Medical News Today).Although this is a sizable number in the population, only 3-10% of cancer cases areattributed to genes. BRCA1 and BRCA2 are the most common types of gene mutationswhich can cause ovarian and breast cancer. f. Other factors: Some factors expose people to cancer through physical effectson cells instead of chemical effects. Asbestos is a prominent example of mineral fiberwhich causes cancer while synthetic fibers include glass and rock wool, wollastonite andattapulgite (Anand 2099). None fiber material which can cause cancer include nickel andcobalt. However, it takes several years of exposure for cancer to develop. Another factoris physical trauma but it is quite rare. However, repeated application of hot objects to thebody for long periods increases the risk of skin cancer.
  7. 7. Cancer 7Treatment Treatment of cancer depends on the type and stage of cancer, as well as age,health and other additional characteristics. Treatment involves a combination of therapiesas well as palliative care and they are classified into surgery, chemotherapy, hormonetherapy, radiation, gene therapy and immunotherapy (Rheingold 112). a. Surgery: As the oldest form of treatment, surgery is preferred when cancer isyet to metastasize since it can be removed and the patient cures completely. Thisprocedure is common in the removal of the breast, testicle or prostate. Cancer cellscannot be completely removed after metastasis (Kuper et al 460). However, surgery isimportant in controlling other symptoms such as spinal cord compression and bowelobstruction. b. Radiation: Commonly known as radiotherapy, high-energy rays are focusedon cancer cells to destroy them (Panno 125). Molecule of the cancer cells are destroyedby the gamma-rays emitted by radium or high-energy x-rays created by a specialmachine. With improvement of technology, it is possible to target beams more accuratelyand spare healthy tissues. c. Chemotherapy: Chemicals are utilized in this process so the cell division canbe affected and thus damage DNA or proteins and this kill the cancer cells. Any cellwhich is dividing rapidly is targeted by the treatment and not just cancerous cells.However, while normal cells tend to recover from the damage induced by the chemical,cancerous cells cannot recover. Chemotherapy is used when cancer has metastasizedsince the medicine moves in the whole body (Samaras et al 270). It is a compulsory
  8. 8. Cancer 8treatment for some form of leukemia and lymphoma and the patient has to rest betweencircles to recover. Side effects include hair loss, vomiting, nausea and fatigue d. Immunotherapy: The goal is to fight the tumor by strengthening the body’simmune system. Local immunotherapy treats the specific area which has been affected bycausing inflammation and the tumor shrinks. Systematic immunotherapy moves acrossthe body and the agent is similar to protein interferon which shrinks tumors (Panno 125).These therapies are still at their initial stages by researchers have recorded success forinstance in antibodies which limit development of breast cancer cells. Another form ofimmunotherapy is one marrow transplant since the immune system of the donor willassist in attacking cancer cells. e. Hormone therapy: Most cancers have a linkage to different types of cancerssuch as prostate and breast cancer. The aim of hormone therapy is to alter production ofhormones to either stop the growth of cancer cells or to kill them (Mucci 480; Meyers221). Estrogen levels are reduced through breast cancer hormone therapies whiletestosterone reduced are reduced through prostate cancer hormone therapies. Lymphomaand leukemia are also treated using hormone cortisone. f. Gene therapy: It is aimed at replacing genes which have been damaged so as toaddress DNA damage. Physicians replace a damaged gene which stops cells fromdividing with a copy of a functional gene. Other gene therapies aim at killing the DNA ofthe cancer cells. This field is still young and is yet to register success.Prevention: Bignold (55) says that cancers attributed to particular behaviors can be preventedeasily. For instance, alcohol and tobacco cause different types of cancers and even a
  9. 9. Cancer 9current user of these products can stop so as to reduce the risk of cancer. Staying inshade, wearing a hat and shirt and applying sunscreen go along way in preventing skincancer. Diets which have low fat and rich in fruits and vegetables also prevent the risk ofcancer: a. Dietary: An individual should minimize food which contribute to weigh gain,sugary drink and energy-dense foods. It is important to eat foods of plant origin andminimize on red meat as well as processed meat (Panno 125). It is important to minimizealcoholic drinks and smoking behavior and reduce intake of salt and mouldy cereals.Studies have shown that grilled meat increases the risk of colon, breast, stomach andpancreatic cancers due to high level of carcinogens. b. Medication: According to Mucci (480), aspirin minimizes the risk of cancerdeath. Moreover, daily use of raloxifene and tamoxifen minimizes occurrence of breastcancer among high-risk women by close to 50 percent (Meyers 221). The risk of prostatecancer is reduced by finasteride but this applies mainly to low grade tumors. Vitaminshave not proved to be effective in prevention of cancer. High levels of Vitamin D tend toincrease the risk of cancer. Beta-carotene supplements increases the risk of lung cancerbut by a minimal margin (World Health Organization). Folic acid supplementation canincrease colon polyps and it does not prevent colon cancer. c. Vaccination: Scientists have developed vaccines which prevent infection bycancer-causing viruses. Therapeutic vaccines are being developed to increase immuneresponse against epitopes related to specific cancers (Bignold 54). Human papillomavirus vaccine reduces the risk of cervical cancer while hepatitis B vaccine protects anindividual from being prevented by hepatitis B thus reducing the risk of liver cancer.
  10. 10. Cancer 10 Work citedAnand, Preetha, Ajaikumar B. Kunnumakara, Chitra Sundaram, Kuzhuvelil B. Harikumar, Sheeja T. Tharakan, Oiki S. Lai, Bokyung Sung and Bharat B. Aggarwal. Cancer is a Preventable Disease that Requires Major Lifestyle Changes, Journal of Pharmaceutical Research, 2008 Volume 25, Number 9, 2097-2116Bignold, Leon P. Cancer: Cell Structures, Carcinogens and Genomic Instability. Basel: Springer, 2006Brenner, Hermann, Dietrich Rothenbacher and Volker Arndt. "Epidemiology of Stomach Cancer". Methods in Molecular Biology, Volume 472, II, (2009). 467-477,Kinzler, Kenneth W and Bert Vogelstein. Introduction: The Genetic Basis of Human Cancer. New York: McGraw-Hill, 2002.Kuper H, Adami HO, Boffetta P. "Tobacco Use, Cancer Causation and Public Health Impact". Journal of internal medicine 251 (6): 455–66.Medical News Today. What is Cancer? What Causes Cancer. 12 june 2011. 1 July 2011., Robert A. Cancer: From Mechanisms to Therapeutic Approaches. London: Wiley-VCH, 2007Mucci, LA, Wedren, S, Tamimi, RM, Trichopoulos, D and Adami HO. "The Role of Gene–Environment Interaction in the Aetiology of Human Cancer: Examples from Cancers of the Large Bowel, Lung and Breast". J Intern Med (2001); 249: 477–93
  11. 11. Cancer 11Panno, Joseph Cancer: The Role of Genes, Lifestyle, and Environment. New York: Infobase Publishing, 2004Rheingold, Susan, Alfred Neugut and Anna Meadows. "156: Secondary Cancers: Incidence, Risk Factors, and Management". In Frei, Emil; Kufe, Donald W.; Holland, James F. Holland-Frei Cancer Medicine (6th ed.). Hamilton, Ont: BC Decker, 2003Samaras, Vassilis, Rafailidis, Petros I, Mourtzoukou, Eleni G, Peppas, George and Falagas, Matthew E. "Chronic Bacterial and Parasitic Infections and Cancer: a review" (PDF). The Journal of Infection in Developing Countries 4 (5): 267–281World Health Organization. National Cancer Control Programmes: Policies and Managerial Guidelines. Geneva: World Health Organization, 2002