||FACTS ABOUT CANCER
Cancer is the second most common cause of death
in most of the countries (the first is heart disease), representing about
one in five deaths. Cancer has become more common during the twentieth
century, not because of population or radiation, but because cancer is
more common in older people. As the number of older people in the
population has increased , so has the frequency of cancer. The disease is
very rare in people in their 20s, but the risk of developing cancer
roughly doubles between ages 30 and 40 and doubles with each succeeding
decade. This means that people in their 70s have twice the risk of cancer
that people in their 60s have, and 16 times the risk of people in their
30s. However, great advances have been made in the diagnosis and
treatment of cancer.
WHAT IS CANCER
Cancer is the unregulated growth and spread of
cells. Cancer is not a single disease, it is a group of diseases in
which a breakdown occurs in the normal processes that control th
multiplication of cells. Almost all our cells need to be replaced
regularly, some cells (such as those that line the intestine) divide
every few hours and are shed after living for only a few days, other
cells live for years. The processes of cell division and growth are
controlled by genes that start and stop the growth process. Some of
these growth controlling genes may undergo changes (mutation) that cause
them to malfunction.
Cell growth is then uncontrolled, the cell divides,
forming more cells with the same mutated genes. Simple overgrowth of
cells may lead to a relatively harmless, benign (not likely to spread0
tumor such as a wart or polyp, but two or three (or more) genes within a
single cell may undergo changes that cause a growth that becomes
malignant, (likely to spread) and invades and damages blood vessels,
nerves, and other body tissues. Invasion of healthy tissues by the
growth of malignant tumor cells is called metastasis. it usually take 10
years or more for a malignant symptoms. Malignant tumor cells may be
carried by the bloodstream or spread through the lymphatic system to all
parts of the body, where they form other tumors. Once a cancer has
metastasized (spread) it is usually incurable. However, treatment can
prolong and improve the quality of life.
WHAT CAUSES CANCER
The three major causes of changes in growth
controlling cells include viruses, chemical, and radiation. Several
human viruses have been shown to cause cancer. For example, the
hepatitis B virus causes a type of liver cancer, some papilloma viruses
are closely linked with cancer of the cervix, and another virus is
responsible for a rare type of leukemia. The most significant chemical
cause of cancer is tobacco, smoking is the cause of most lung cancers
and is an (continued on coming pages).
Important factor in canners of the tongue, larynx,
esophagus, cervix, and bladder. Chewing tobacco can cause mouth and
tongue cancer. Workers who are exposed to chemicals such as benzene,
coal tar, rubber, and some plastic can develop cancers of the blood
cells, kidneys, bladder and liver. Radiation from radioactive isotopes X
rays, and nuclear waste can cause cancer, especially some types of
leukemia. The main radiation hazard is sunlight, which causes most skin
cancers. People with fair skin that is repeatedly exposed to excessive
amounts of direct sunlight have an increased risk of developing skin
These factors do not, however, always cause cancer
in everyone who is exposed to the risk, for example, only a minority of
people who have ever smoked cigarettes get lung cancer (although many
others die prematurely of chronic illnesses such as heart diseases and
emphysema). In part, this is because some people are genetically more or
less susceptible development of cancer include the amount of alcohol
that you drink and the ability of your body's immune system to detect
and destroy cancer cells at an early stage.
WHAT ARE THE CHANCES FOR A CURE?
The key to curing some
types of cancer is early diagnosis and treatment. Successful treatment
is far less likely once malignant cells have spread from the original
tumor to form cancers in other parts of the body.
Tests currently used to detect cancer are designed
to achieve early diagnosis. Mammography, for example, detects possible
breast tumors in women when such tumors are still too small to be found
by physical examination of the breasts tumor is under half an inch in
diameter at diagnosis.
Regular Pap smears in women detect precancerous
changes in the cervix at an early stage when treatment is simple and
effective. The death rate from cancer of the cervix has fallen
dramatically in recent years in communities where most women have
regular Pap smears.
There is evidence that regular examination of the
intestine (colon) in people over age 50 improves survival from cancers
of the rectum and colon.
When cancer is suspected, imaging techniques reveal
accurate details of tumors, increasing the chances of successful
treatment; these chances of successful treatment; these techniques
include CT scans, MRI scans, and radio nuclide scans including PET scan.
Also, many internal organs can now be examined directly by endoscopy
(examination with a viewing tube).
Advances have been made in treatment as well as in
diagnosis of cancer. Drugs may be injected directly into the arteries
that supply blood to a tumor, thereby allowing a more targeted
destruction of the tumor. In addition, reconstructive plastic surgery
offers the possibility of restoring a person's appearance after major
sugary on the breast, head or neck. Some forms of chemotherapy and
treatment with hormones are more effective and less difficult for the
patient than treatments used in the past. For example, tamoxifen, the
drug used most commonly to treat breast cancer, has few major side
effects in most women. Radiation therapy, too has become more precise
and therefore is more effective and causes fewer side effects.