Definition:
 Cancer:
a malignant neoplastic disease - (any malignant growth
or tumor caused by abnormal and uncontrolled cell division;
it may spread to other parts of the body through the lymphatic
system or the blood stream).
The
World Health Organisation estimates that six million people
worldwide die annually from cancer. While there have been
remarkable strides in understanding cancer biology and
in improving cancer therapy, the combined death rate from
all cancers is not dramatically different from what it
was 25 years ago, but survival rate and time have improved.
The causes of most cancers are still unknown although
occurrence increases with age and multiple risk factors
have been identified. Yet cancer probably the most widely
feared disease in the world - remains poorly treated.
Nevertheless,
considerable progress has been made in palliative and
adjuvant therapy. Today drugs that specifically interfere
with defined targets in the cell cycle and thus inhibit
uncontrolled cellular growth and division can significantly
enhance the quality of care for cancer patients.
Cancer
is classified by the part of the body from which it originated,
and by its image under the microscope. Various types of
cancer differ in their rates of development, patterns
of spread, and reaction to different types of therapy.
That's why individuals with cancer need specific
treatment aimed at their particular form of the ailment.
In the USA, 50% of all men and 33% of all women will acquire
cancer during their life. Nowdays, millions of people
can live with cancer or have been cured of the condition.
The risk of developing most cancers can be reduced by
changes in a person's lifestyle, for example, by stopping
smoking or eating a better diet. The sooner a cancer is
found, and the sooner treatment can begin, the higher
a patient's probabilities are of a cure.
Cancer
Prevention Strategies:
Everyone
knows that the word "chemotherapy" means using
pharmaceuticals to treat cancer. But there's another important
term that may be less familiar to you: "chemoprevention,"
the use of pharmaceuticals to prevent cancer.
Of
course, the continued search for cancer treatments and
cures is essential, but some scientists are taking a more
proactive view. Instead of focusing on the "end-game"
of treating cancer; they are looking for ways to identify
pre-cancerous events and conditions so they can intervene
before the cancer becomes a grave concern.
It
makes perfect sense, really. If pharmaceuticals can treat
invasive cancers, then it seems reasonable to assume that
pharmaceuticals and other substances might also be used
to stop cancer in earlier stages. That idea is the basis
for chemoprevention.
Cancer
occurs when a gene mutates unfavorably during the process
of cell division. Since cell division is continuous, human
cells undergo billions of divisions in a lifetime. Indeed,
the longer we live, the greater the number of cell divisions…
and the greater the chance that something will
eventually "go wrong" in the process. In some
people, there is a genetic (family) predisposition for
this kind of aberrant cellular event. In others, the mutation
may be environmentally triggered.
Although
the possible combinations of heredity and environment
seem virtually infinite, it is generally accepted that
"...future cancer prevention strategies will hinge
on studying both genetic profiles and environmental exposures."
The overall goal of cancer prevention research is to determine
WHO is likely to develop WHAT kind of cancer related to
WHICH environmental trigger. Some day we may be able to
take a pill that prevents the ravages of cancer in much
the same way as we now have pills to lower blood pressure
or reduce cholesterol.
Glimpses
of the Future - Chemoprevention:
Many
research studies point to factors that influence the development
of cancer, and they offer us a glimpse into the potential
for cancer chemoprevention. Various nutrients, phytochemicals
(plant chemicals), and pharmaceuticals are already being
investigated for use in chemoprevention. Here are some
examples:
Nutrients
may affect the development of cancer in some people.
Deficiencies
of vitamins B12 and B6 can damage replicating DNA and
damage chromosomes, sometimes causing cancer.
A
selenium deficiency may increase the incidence of epithelial
cancers in some people.
Vitamin
E may lead to reduced incidences of prostate cancer.
Consuming
some types of dietary fiber may help to prevent colorectal
cancer in some people.
Some
pharmaceuticals are already being investigated with
regard to their potential in preventing cancer.
Daily
low-dose aspirin may lower the risk of colon cancer
in some individuals.
Tamoxifen
protects some high-risk women from breast cancer.
Raloxifene
lowers cancer risk in some healthy women.
More
than 4000 phytochemicals have been identified, and scientists
are exploring how they may affect cancer risk and cancer
development. "Some phytochemicals act as antioxidants
but may also have a role in the formation of cancer-causing
chemicals and/or the suppression of cancer development."
Many studies are investigating various phytochemicals
and their potential for cancer prevention - for example:
Phytochemicals
(tannins) in red raspberries (Ellagic Acid)
Polyphenols
(catechins) in tea;
Carotenoid
(beta carotene and lycopene) in carrots and tomatoes;
Indoles
in cabbage and broccoli;
Isoflavones
in soybeans and other legumes.
Ongoing
Cancer Research Efforts:
A large number of studies have been aimed at advancing
our knowledge of the causes of cancer and identifying
substances that may prevent its occurrence or stamp
it out in the early stages of development. The fact
that the National Cancer Institute (NCI) has 60 ongoing
clinical trials of chemopreventives signals the importance
of chemoprevention as a proactive approach for fighting
cancer.
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