About Cancer
"Cancer" is an ancient Greek word meaning a crab.
It describes the crab-like appearance of malignant tumors with
a central mass and tendrils growing out into the surrounding tissues.
Cancer has been known as a disease ever since there was a record of
human history.
Pictures showing people with tumors on different parts of their bodies
could be found on the walls of Egyptian tombs in ancient times.
For many centuries, the only treatment available for cancer was surgery.
The success rate was poor because tumor cells left after surgery could
continue to grow until the patient was dead.
The first attempts at drug treatment of cancer were in the mid-1800s.
A variety of poisons such as arsenic were tried in an
attempt to kill the cancer cells. Unfortunately,
all too often, it was the patient that was killed.
The discovery of anaesthetics shortly afterwards enabled
more sophisticated surgery, which dominated cancer treatment
for the next seventy years.
In the early 1940s, sailors injured by
mustard gas in an explosion were noted to lose
their white blood cells and bone marrow cells. The observation
hinted at a possible treatment of Hodgkins Disease, a cancer of the
white blood cells. In 1943, doctors started to treat Hodgkins Disease,
a once always fatal disease, with mechlorethamine,
a drug closely related to mustard gas.
It was a great success and over half of the patients were cured.
Over the next twenty years, a whole range of anti-cancer drugs were
developed.
Still today, the majority of anti-cancer drugs are toxic, killing
both cancer and normally dividing cells.
Despite serious side effects, cancer chemotherapy has saved
the lives of many cancer patients.
Today, it remains to be the mainstay treatment for metastatic cancer.
The need of developing safer drugs is obvious but it is difficult.
The bottom line is to identify and target cancer-specific survival
mechanisms. For instance, some cancers,
such as breast cancer and prostate cancer, rely on
certain hormones to grow so we can develop drugs that block the effect
of the hormones.
The discovery of oncogenes (first one in the early 1970s)
promises new anti-cancer drugs. Many different oncogenes are known and
the complex mechanisms by which they work are under investigation.
Now that we understand the basic cause of cancer, we envision more
effective and safer drugs that block the actual cause of cancer itself.
Cancer Incidence Rates (from National Cancer Institute)
For males, cancer incidence rates
for all sites combined ranged from 493.8 per
100,000 in Tasmania, Australia, to a low of 59.1 in The Gambia.
Rates for U.S. males were 351.3 for blacks and 330.4
for whites.
For females, rates for all sites ranged from a high of 345.4 per 100,000
in British Columbia, Canada, to a low of 39.6 in The Gambia.
The comparable rate for U.S. white females was 277.0 and for black
females was 227.1 per 100,000.
References:
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Association for International Cancer Research.
http://www.aicr.org.uk/progress/cancer1.htm
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National Cancer Institute.
http://www.seer.cancer.gov