| The term cancer actually
refers to more than 100 diseases. What they all have in
common is the uncontrolled growth and spread of cells
that have become abnormal.
Cells dividing to produce more cells is basic to your
body's continued health. However, when new cells that
your body doesn't need are produced, they can form a
mass of tissue called a tumor. Some tumors are benign,
meaning that they aren't cancerous.
Malignant tumors are cancerous. They can invade and
damage tissues and organs located near the primary tumor.
Cells can also break off from the original tumor and
travel to other parts of the body, where they form new
tumors -- a process called metastasis.
How Does Cancer Develop?
The initiation phase of cancer consists of damage to
the genetic material, called DNA (deoxyribonucleic acid),
found in cells. Initiation typically is caused by a
carcinogen --anything that can damage cells in a way
to make them cancerous.
Carcinogens activate special genes, known as oncogenes,
present in the cells. Oncogenes normally control cell
growth and multiplication. When activated by a carcinogen,
however, oncogenes initiate and continue the conversion
of normal cells into cancer cells.
Another genetic change that can lead to cancer is the
suppression or loss of tumor-suppressor genes, which
normally produce proteins to inhibit cell division.
Potentially cancerous cells are being formed in the
body at anytime under certain circumstances. Why doesn't
everyone develop cancer, then? For one thing, the immune
system destroys many abnormal cells before they have
a chance to multiply.
Another way the body gets rid of old or damaged cells
is called apoptosis. Each cell has a life span programmed
into its DNA and divides a specified number of times
before it naturally dies. This programmed cell death
regulates the number of cells in tissues and eliminates
many potentially dangerous cells in the body, including
cancer cells.
Cancer may occur when some abnormal cells escape these
safeguards. In the second phase of cancer, called promotion,
abnormal cells are stimulated to grow and multiply to
establish cancer.
Who Is at Risk of Cancer?
Virtually everyone-men, women, and children- is at some
risk of developing cancer. Cancer risk increases with
age. Almost 80% of all cancers are diagnosed in people
aged 55 and older.
A small percent of cancers are hereditary,
that is, the malfunction of the oncogene is inherited.
However, the vast majority of cancers result from damage
done by carcinogens. Here are some major risk factors
for cancer.
Risk Factors
| Exposure to tobacco smoke and/or
smokeless tobacco |
Smoking accounts for 85% of lung
cancer deaths. |
| Diet |
High-fat diet may be linked to cancers
of the breast, colon, uterus, and prostate. |
| Overweight and obesity |
Serious overweight appears to be
linked to increased risk of cancers of the prostate,
pancreas, uterus, colon, ovary, and breast (in older
women). |
| Exposure to ultraviolet radiation |
Ultraviolet radiation from sunlight,
sunlamps, and tanning booths can cause skin cancer. |
| Alcohol use |
Drinking large amounts of alcohol
may increase the risk of cancer of the mouth, throat,
esophagus, and larynx (especially in a cigarette
smoker), the liver, and, possibly, the breast. |
| Radiation |
Exposure to large doses of radiation
from medical X-rays may increase cancer risk. |
| Chemicals and other substances in
the workplace |
Exposure to certain metals, dust,
chemicals, or pesticides can increase cancer risk.
Known carcinogens include asbestos, nickel, cadmium,
uranium, radon, vinyl chloride, benzene, and benzidene.
|
| Hormone
replacement therapy |
Estrogen
alone increases the risk of uterine cancer; adding
progesterone
reduces this risk. High doses or long-term use of
estrogen both appear to increase breast cancer risk.
|
| Diethylstilbestrol (DES) |
Some daughters of women given DES
during pregnancy have an increased risk of developing
abnormal cells in the vagina and cervix. |
| Family History |
A few cancers, including cancers
of the breast, ovary, and colon and melanoma,
tend to run in families. |
| Viruses |
Certain cancers are known to be
related to viral infections. |
Adapted from reference 1 and 2.
Cancer in Women
On average, every 6.4 minutes a woman in the US will
be diagnosed with a cancer of the reproductive organs...
ovarian, uterine, cervical, vulvar, vaginal or tubal.
Each year approximately 82,000 women will be told they
have one of these diseases. Youth doesn't protect you
from this disease -- it strikes women in their teens
as well as postmenopausal women over 50.
Breast cancer is occurring in epidemic proportions
in the United States. It is the second leading cause
of cancer death in American women and will result in
an estimated 40,800 deaths in 2000. About one of every
nine women will develop breast cancer during her lifetime.
African-American women, who are less likely than white
women to develop breast cancer, are more likely than
white women to die from it.
The cervix, the narrow neck of a woman's uterus, can
go through a series of changes that eventually can lead
to cancer. Cervical cancer is the third most common
form of cancer of the female genital tract and accounts
for 19 percent of these cancers. Cervical cancer occurs
almost twice as often in younger African-American than
in age-matched white women.
Cancer of the uterus accounts for 5 percent of all
cancers in women and is the most common gynecological
cancer. Most cancers of the uterus occur in the endometrium,
the lining of the uterus. Endometrial cancer occurs
most often in older women; it is rare before age 40.
Cancer of the ovary is the second most common gynecologic
cancer and the fourth leading cause of death from cancer
among women. It generally develops after menopause and
is seen more often in women who have had no children
or who had trouble conceiving.
Cancer of the vulva and vagina are rare and occur most
often in older women. Warning signs include a lump or
sore on the vulva (external genitals) or in the vagina.
References
View cancer
references list.
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