Cancer

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Cancer
Introduction
Cancer is uncontrolled growth of a group of cells which invade and destroy adjacent tissues, and can move to other parts of the body. The abnormal cells are called malignant cells, cancer cells or tumor cells. There are more than a hundred types of cancer 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 of tissues (tumors) are formed (Anand et al 2097). Tumors affect the normal systems of the body such as circulatory, digestive and nervous systems, and produces hormones which alter normal body function. Benign tumors are ones which demonstrate limited movement and growth. Malignant tumors are the most dangerous and they form when the following happens: cancer cells move across the body through the blood or lymph systems and destroy healthy tissue; and when a cell divides and forms blood vessels and feeds itself through a process known angiogenesis (Kuper et al 460). A tumor can move successfully to different parts of the body and grow, invade and destroy tissues which are healthy. The tumor will be said to have metasized. This document will critically evaluate the symptoms, causes, diagnosis, treatment and prevention of cancer. This paper will explore the subject matter of cancer, with a close attention levied to malignant tumors
Symptoms and signs
Symptoms of cancer are different and they depend on the location of cancer, the size of the tumor and where it has spread. It is possible to see or feel cancer through the skin. 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 skin changes. In addition, Kinzler (134) says that some forms of oral cancers can make the tongue 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 since crucial cognitive functions will be affected. Cancer of the pancreas is often small for the symptoms to be realized early.
It is only realized when pain is felt after squeezing the nerves which are close or affects the functions of the liver. This can make the eyes and skin to turn yellow, a condition known as jaundice. Moreover, as the tumor continues to grow, symptoms start to 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 changes in the size of stool (Mucci 480). Prostate or bladder cancer can affect the functions of bladder by causing frequent or infrequent urination. Symptoms which can occur include excessive sweating, fast weight loss, fever, fatigue and anemia.
Brenner et al (470) say that these symptoms are also common in other types of problems. For instance, hoarseness and coughing may indicate throat or lung cancer, or any other ailment. After cancer has metastasized, the affected area will produce other symptoms. Enlarged or swollen lymph nodes can appear early in the disease. However, if the spread of cancer affects the brain, an individual is likely to experience seizure, vertigo and headaches. When the lungs are affected, an individual will cough constantly and experience shortness of brain. The liver tends to enlarge leading to jaundice while the bones are likely to be brittle, painful and break easily. Rheingold (213) says that the symptoms of a metastasis will be determined ultimately by the areas which have been affected by the spread of cancer.
Classification: Cancer has been classified into five broad categories. First, Carcinomas are cancers which start in the skin or tissues that cover internal organs. Since they are derived from epithelial cells, they cover both internal and external body parts such as breast, 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 et al 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 nymph nodes. This group of cancer is derived from hematopoietic cells. Fourth, Leukemia are cancers which start in the bone marrow and ultimately accumulate in the bloodstream lastly, 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 is greatly improved. Most cancers are recognized when signs and symptoms begin to appear or after screening (Panno 125). However, these methods still lack an exact diagnosis and an individual must visit a pathologist who will investigate the symptoms using medical tests. Such tests include blood tests, endoscopy, X-rays and CT scans. All these are imaging tests which detect the location of a tumor and the types of organs which have been affected.
Pathology: To get a definitive pathology for several types of malignancies, a pathologist has to carry out histological examination of cancer cells. Surgery or biopsy is used to obtain tissues. Skin, liver and breast biopsies can be done from a doctor’s office but other tissues require an operation under anesthesia. Diagnosis of a tissue indicates the nature of a cell, genetic abnormalities, histological grade and different characteristics of the tumor (Brenner et al 474). Immunohistochemistry and Cytogenetics are forms of pathological tests which can also be performed on a tissue.
Causes
Research evidence indicates that 90 to 95 percent cases of cancer are caused by environmental factors while only 5 to 10 percent is attributed to genetics (Anand et al 2097; World Health Organization). Cancer researchers say that the word environmental refers to all those causes not related to genetics. Some of the environmental causes which are 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 are linked 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 carcinogens which includes polycyclic aromatic hydrocarbons and nitrosamines (Mucci 481). One in every three cancer deaths in developed countries is attributed to tobacco while the rate is one in every five across the world. 2-20% of cancer is believed to be related to the profession of an individual. Across the world, close to 200,000 cancer deaths are reported and they relate to occupational risk factors (Medical News Today). For instance, inhaling tobacco 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 physical activity 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 of cancer. Physical inactivity puts an individual at risk of cancer not just because of the body weight but other negative effects on the endocrine and immune system. Foods which 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 liver cancer, wile Betel chewing is attributed to oral cancer.
c. Infection: Infectious diseases causes close to 18% cancers worldwide. This rate varies from region to region with Africa recording the highest (25%) and the lowest in developed countries (10%) (...