13. CANCER and its types and side effect

Caner and its side effects

1. CANCER

2. A basic characteristic of life and growth is that body cells reproduce in an orderly and controlled fashion. Scientists know what the normal pattern of tissue growth looks like . Irregularities in this process can cause unrestricted cell growth , usually forming a tumor called a neoplasm . Oncogenes regulate cell division , but genetic processes and carcinogens can damage them , causing unrestricted growth. Some neoplasms are harmless, or benign , but others are malignant . Cancer is a disease of the cells characterized by uncontrolled cell proliferation that usually forms a malignant neoplasm. Cancer

3. There are many forms of cancer, and the large majority can be classified into five types based on the kind of tissue in which it develops: 1. Carcinomas , which are malignant neoplasms in cells of the skin and the lining of body organs, such as the digestive , respiratory, and reproductive tracts. About 85 % of human cancers are carcinomas. 2. Melanomas , or neoplasms of a special type of skin cell that produces the skin pigment called melanin. 3. Lymphomas , or cancers of the lymphatic system. 4. Sarcomas , which are malignant neoplasms of the muscle, bone , or connective tissue. 5. Leukemias , or cancers of the blood-forming organs , such as the bone marrow, that lead to an extreme proliferation of white blood cells. Forms of Cancer

4. An important characteristic of cancer cells is that they do not adhere to each other as strongly as normal cells do. As a result, they may separate and spread to other parts of the body through the blood or lymph systems. This migration is called metastasis . As the neoplasm or tumor grows, it must eventually recruit its own blood supply for nutrients, a process called angiogenesis .

5. Cancer progresses by enlarging and spreading to different sites; its growth at each site interferes with normal development and functioning. As the disease progresses , it can produce pain, often because the tumor creates pressure on normal tissue and nerves or blocks the flow of body fluids. The disease leads to death in direct and indirect ways . In the direct route, the cancer spreads over time to a vital organ, such as the brain, liver, or lungs; it then competes for and takes most of the nutrients the organ tissues need to survive, thereby causing the organ to fail. Cancer kills indirectly in two ways: the disease itself weakens the victims, and both the disease and the treatment can impair the patient’s appetite and ability to fight infection. THE SITES, EFFECTS, AND CAUSES OF CANCER

6. The prognosis for cancer depends on how early it is detected. Cancer is caused by the interplay of genetic, environmental, and behavioral and psychosocial factors. Environmental factors include ultraviolet radiation, and household and worksite chemical hazards. Behavioral or lifestyle factors include smoking, diet, obesity, and physical activity. Stress and related psychosocial factors seem to play a role in the development and course of cancer, probably through the effects of stress on the immune system and the process of metastasis and angiogenesis. Some research has also found a link between certain viral infections and the development of some cancers, such as in the cervix and in the liver. Prognosis and Causes of Cancer

7. The risk of developing cancer typically increases with age , especially from the middle-age years onward: over 75% of all cancers are diagnosed in people 55 years of age and older. Taking age into account, the incidence rates of cancer are higher for males than females in many countries. Age, Gender, and Sociocultural Factors in Cancer

8. People can increase the likelihood of early rather than late detection of certain cancers by knowing the warning signs of cancer and having or doing regular examinations. Diagnosing cancer can involve three medical procedures: First , blood or urine tests can suggest the presence of cancer by revealing telltale signs, such as unusual levels of certain hormones or enzymes. Second , radiological imaging , such as with X-ray and MRI, allows physicians to see the structure of internal organs and whether a tumor exists. Third, in a biopsy a physician takes out a small piece of suspicious tissue and has it analyzed. DIAGNOSING AND TREATING CANCER

9. There are basically three types of treatment: Surgery Radiation Chemotherapy Types of Medical Treatment