Essay/Term paper: Cancer

Essay, term paper, research paper:  Medicine

Cancer


Right now, cancer is one of the most feared diseases in the world. In
the early 1990s almost 6 million new cancer cases developed and more than 4
million deaths from cancers occurred. Also more than one-fifth of all deaths
were caused by cancer and it has been predicted, by the American Cancer Society,
that about 33% of Americans will eventually develop this disease. This is a huge
disease that is killing people all over the world.
The field of cancer study is called Oncology. The government has spent
billions of dollars on research of this fatal disease. Cancer is the most
aggressive disease of a larger class known as neoplasms. Neoplasms do not fully
comply with the parts of the cell that control the growth and functions of the
cell. These cells eventually become abnormal growths and can be recognized as
not normal tissue. These traits are passed down as the cell reproduces therefore
spreading the cancer.
Neoplasms are generally classified into two groups: malignant and benign.
Malignant tumors, or abnormal tissue, grow more rapidly than benign tissue and
they invade normal tissue. Benign tissue is structured similar to normal tissue
while malignant tissue is abnormal and has an unstructured appearance. Of
greater importance, benign tissue does not metastasize, or begin to grow in
other sites, like malignant tumors do. Cancer always refers to metastasized
tumors but the term tumor is not always necessarily cancer. A tumor is any
living tissue that is distinguishable as abnormal living tissue. After a
cancer forms, it can also change from a benign to a malignant state, therefore
making the cell grow at a more rapid rate. The development of the cell starts
when it forms notable abnormalities in chromosomes and then multiplies
exceedingly. Then metastasis usually occurs and generally causes the death of
the host. There are many different cancers which form on just about all parts of
the body. In the US, skin cancer is the most common cancer, then prostate
cancers in males, and then breast cancer in women. Leukemia is clearly the
dominant cancer in children. The number one killing cancer in the world today is
lung cancer, mostly caused by the smoking of cigarettes. Some researchers have
stated that if Americans stopped smoking, lung-cancer deaths could disintegrate
within two decades. Stomach cancer is the second most fatal cancer in males and
Third is the leading cancer in women, breast cancer. The prevention of
cancer rides upon what is known about the causes. Any agent that causes cancer
is called a carcinogen. Carcinogens are generally classified into three groups-
chemical, biological, and physical. Chemicals that cause cancer have many
different molecular structures and can be just about any type of chemical. Some
substances that cause cancer are complex chemicals and gases, certain metals,
drugs, hormones, substances in molds and plants and many more. Many
nitrosamines, or simple organic oxides of nitrogen, are carcinogenic. That and
hydrocarbons are carcinogens in cigarette smoke and increase the risk of lung
cancer. Also another chemical gas, vinyl chloride, gas has been found to be an
agent of sarcoma of the blood vessels in the liver. Many drugs as well as
alkylating agents used to treat cancer are carcinogenic. Even though these
chemicals break the DNA of cancerous cells, which kills them, it also induces
cancer in normal cells. Some hormones created in humans can also cause cancer.
High levels of estrogen, which is marked as a female hormone, can increase the
chances of getting a cancer of the uterus (in women). Aflatoxin B is a substance
produced by the mold Aspergillus that causes a number of cancer, but generally
liver cancer. Many carcinogens have not been discovered but research is being
done to discover other carcinogens to keep people aware and safe. There are also
many different biological agents which cause cancers. The most common biological
agents are the oncogenic viruses that commonly bring about the formation of
neoplasms in some smaller animals. Also some of these viruses are thought to
cause human cancers, and one has even been proven to cause leukemia. These
viruses can be split into DNA viruses and RNA viruses, depending on their
genetic structure. The DNA viruses generally insert the genetic information
straight into the cells of their host. The RNA virus, contrasting, requires that
the genetic information be transcribed into DNA by an enzyme, called reverse
transcriptase, provided by the virus. All onconogenic viruses have one or more
genes that are needed for the transformation of the infected cell into the
neoplastic cell. These genes, called oncogenes, are best portrayed in the
genomes of oncogenic RNA virus. It is now seen that the oncogenes have close
relation with the counterparts in the normal cells which they infect. The
oncogene, nonetheless, has a different structure and appears to be activated and
expressed abnormally by one mechanism or another, leading to transformation in
the cell. Some oncogenic viruses may activate the normal cellular counterparts
of oncogenes, called c-oncogenes, thus causing the neoplastic transformation to
occur. Similar reactions may be a result from the action of chemicals or
radiation or both. Ultraviolet and high-energy radiation are also agents for
some types of cancer. A bond exists between exposure to the sun"s ultraviolet
rays and the occurrence of skin cancer in humans. Some cancers caused by
radiation are leukemia, along with cancers of the thyroid, breast, stomach,
uterus, and bone. Consequently everyday diagnostic tools such as the X ray are
used very carefully so that a person is not overexposed. Physically induced
sarcomas can also be induced when films or disks are enclosed under the skin, as
done in experimental animals. After the implant has been in the animal for many
years, sarcomas usually develop around the implant. If the implant is pulverized
or its structure is markedly altered before insertion, no sarcomas develop. This
shows that the physical structure causes the cancer, other than the chemical
composition. Even though it is unknown why cancer happens in some people and not
in others heredity seems to have an effect in some forms of cancer. Because of
this, family history may be significant in predicting and diagnosing cancer.
Prevention is the best way to avoid cancer. Since the majority of cancer is
related to the environment, it would be best to identify and control these
factors. There are two tests to discover carcinogens. The Ames test measures the
ability of a substance to cause mutations in bacteria and is more than 90
percent effective. The alternative is animal testing. It is exhausting and
expensive work but it is the only certain way to be sure if a particular agent
is carcinogenic. One of the most important ways to protect yourself is early
detection. It is stressed that you get treatment as soon as possible. The
American Cancer Society has come up with seven warning signs of cancer to help
you identify cancer symptoms and get help early. They are: 1.a change in bowel
or bladder functions; 2.a sore that does not heal; 3.unusual bleeding or
discharge; 4.a thickening or lump on the body; 5.indigestion or trouble
swallowing; 6.an obvious change in a wart or mole; and 7. A nagging cough or
hoarseness. If one or more of these symptoms are present a person is advised to
see a doctor immediately.
If treatment of a cancer is to be successful, the diagnosis must be as
early as possible. Though no tests have been discovered to detect all cancers,
there are tests to pick up some. A pap test is used to search for cancer of the
uterine cervix. Mammograms are used to detect breast cancer and blood and stool
tests are used to find colon cancer. There are many other tests besides these to
test for all different types of cancer. There are really three different types
of cancer. Surgical removal is the first, it is the most basic treatment. It is
used to remove the cancerous legions in the body. The second is radiation
therapy, which uses radiation to try and kill the tumor. One of the main
problems with that is not only does it kill cancerous tissue, it also kills
healthy ones. The third way to treat cancer is chemotherapy, which is treatment
by chemical agents. The chance of complete cure is not common but it is usually
used to increase the life of the carrier. The desired effect of treatment in
cancer patients is remission, where the cancer is gone from your body and if it
does not return within 5 years it is considered cured.
Right now the government is spending huge sums of money on cancer
research. They are continuously finding cures and finding better ways to treat
and deal with cancer. Research has come very far and helped many people fight
cancers. Thanks to all the work done, cancer is still a dreaded disease but is
now curable which gives many people faith in recovery.

Bibliography

Compton"s Encyclopedia(1992). Cancer . Chicago: Compton"s Learning Company

Encyclopedia Britannica(1992). Cancer. Chicago: Encyclopedia Brittanica, Inc.

American Cancer Society website(1996): http://www.cancer.org/acs.html