Students Cancer Paper

Authors: Steven Fizer, Richard George,Kelly Parks, Chris Purcell

Jump Menu [Cancer Defined] [Types of Cancer] [Causes of Cancer] [Viruses] [Recognizing Cancer] [ABCD Principle] [Treatments] [Hope for new Cures] [Facts about Cancer] [References]
Introduction: What is Cancer?

Cancer is the abnormal and unrestrained growth of otherwise normal cells. One of these new growths is called a neoplasm. One characteristic of a cancerous cell is that it may lose the ability to differentiate. Differentiation occurs when cells change physically to form body tissue. A group of these combining cells form a tumor. There are two kinds of tumors: benign and malignant. Benign tumors are relatively harmless and carry no serious consequences. However, malignant tumors share some attributes, such as a high rate of cell growth and reproduction, and the tendency to spread to parts of the body other than the afflicted area. Either benign or malignant tumors can be classified by the type of tissue the tumor attacks. Usually benign tumors are enclosed in a capsule of connective tissue, whereas malignant ones are not encapsulated at all.

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Types of Cancer

There are two large groups into which all kinds of cancer are placed, sarcomas and carcinomas. Carcinomas occur in the epithelial tissues covering the outside of the body, such as the skin, and the internal surfaces, such as the alimentary tract. The term sarcoma is applied to cancers of the connective tissues, such as muscles, bones, or binding tissues. A carcinosarcoma is a hybrid of the two.

The most common types of skin cancer are basal-cell epitheliomas, and squamous-cell epitheliomas. These attack exposed and oily skin and cause lesions. Most of the basal-cell diseases are curable, though.

Lung cancer begins in the bronchial passageways in the lungs or leading to the lungs. Lung cancer may metastasize, or spread, to the lymph nodes in the neck and chest. Metastasis is the spreading process cancers use to travel throughout the body. Metastases are the new sites at which the traveling cancers make their home. The main pathways of metastasis are the lymphatic system and the blood vessels. Most metastases occur in the lymph nodes, which are part of the lymphatic system. Different types of cancer and their tumors behave differently. Some cancers travel only through the cardiovascular system and some only visit the blood vessels occasionally.

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Causes of Cancer

Many different circumstances can contribute to cause cancer to infect a person. Lung cancer may be caused by continual smoking of cigarettes and skin cancer is caused by too much direct contact with the sunęs deadly rays. On the other hand, many chemicals are hazardous and can cause cancer, such as asbestos or coal tar. Coal-tar fumes which are inhaled by workers contribute to lung cancer. Dangerous radiation, such as X-ray, radium, or simply intense sunlight and its ultraviolet rays can cause varying types of skin cancer. In unusual cases, leukemia and other kinds of cancer can be genetically inherited. For example, when an identical twin develops a case of leukemia, the other twin has a 15 percent chance of contracting the disease. This is an example of a faulty clonal marker, or an error in DNA. Researchers at Johns Hopkins School of Medicine have developed a test that screens several kinds of cancers. The test seeks out DNA markers and matches them to markers which had been previously found in cancer patients. Also, new research has been done which finds a rare genetic disease, ataxia telangiectasia mutated, more commonly called ATM. ATM increases the risk of cancer in a person by three to five-fold. People with ATM are very susceptible to X-rays.

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Viruses That Cause Cancer

Many viruses which cause cancer have been discovered. One is the Epstein-Barr virus, which combines with Burkittęs lymphoma to cause a kind of herpes. Certain pesticides have been proven to cause some types of cancer in experiments with laboratory animals. Arsenic found in well water can cause skin cancer in regions of Taiwan. Usage of tobacco products is widely regarded by many scientists and researchers to cause cancer often resulting in death.

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How to Recognize the Signs of Cancer-CAUTION

In order to recognize the signs of cancer, many different rules and expectations have been developed. A popular mnemonic used is CAUTION:

Change in bowel or bladder habits
A sore that does not heal
Unusual bleeding or discharge
Thickening or lump in breast or elsewhere
Indigestion or difficulty in swallowing
Obvious change in wart or mole
Nagging cough or hoarseness

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The ABCD Rule
Early warning signs of skin cancer can be recognized by using the ABCD rule:

Asymmetry, Border, Color, Diameter.
Asymmetry--most melanomas are asymmetrical, which means that they are strangely shaped and are not circular.
Border--when the borders of a marking or mole are uneven or blurred, it may mean an early sign of cancer.
Color--the marking or mole may have different shades or stripes of mixed colors.
Diameter--cancerous moles are wider and larger than normal markings.

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Ways to Treat Cancer

There is no complete cure for cancer. There are several methods of treating it, however. The most practiced are radiation, surgery, and medicine. In surgery, the surgeon tries to remove as much of the offending growth as possible. Radiation, or chemotherapy, kills tissues of all kinds. However, since malignant tissues grow faster than normal tissues, they are destroyed faster when exposed to radiation. The most common medicines used for treatment of cancer are nitrogen mustards. These are primarily made of elements such as nitrogen, chlorine, hydrogen. These mustard gases are used to shrink the neoplasm. Nitrogen mustards are mainly used to treat leukemia and Hodgkinęs disease. Radioactive iodine, taken orally, treats some thyroid cancers.

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Hope for Experimental Treatments

Some treatments are experimental. New treatments being tested are hyperthermia and photodynamic therapy. During hyperthermia, the tissue which is attacked by the tumor is subjected to high temperatures, which takes away some of the substances that the cancerous cells need to live. Photodynamic therapy refers to the process of exposing cancer cells to light rays. The U.S. Food and Drug Administration has approved one of the photosensitizing agents to be used in photodynamic therapy, dihematoporphyrin ether.

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Assorted Cancer Facts and New Research:

New research has been done on marine animal colonies called sea mats. They possess cancer-killing chemicals such as bryostatin 1. This chemical prolonged life-span of mice with leukemia, lymphoma or melanoma.
Many foods ward off or promote cancer. For example, women who use olive oil instead of other vegetable oils have a smaller chance of contracting breast cancer.
A new technique called scintimammography can detect cancerous lumps with a ninety percent accuracy.

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References

[Internet Sites]

National Institute of Health
The University of Pennsylvania Cancer Center (Accessed 2/8/96)
National Cancer Institute

[Text Resources]

Dudrick, Stanley. Cancer. Springhouse Corporation, Springhouse, PA. 1986.
Miller, Benjamin. The Modern Medical Encyclopedia. Vol. 2. Golden Press, New York. 1972.
Read, Clifton. Can We Conquer Cancer? Public Affairs Committee. 1973.
Readers Digest. News from the World of Medicine. May, 1995. p. 149.
Readers Digest. News from the World of Medicine. June, 1995. p. 135.
Readers Digest. News from the World of Medicine. July, 1995. p. 100.
Readers Digest. News from the World of Medicine. Nov. 1995. p. 127.

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Submitted by Jennifer Hvozdovic and Dennis Green. Jennifer is a Masters student in the Health and PE Program at Virginia Tech. Dennis is an assistant principal in Carrol County, VA. Thanks for contributing to PE Central!

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